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22
Gen
2013
Xtrabackup for Dummy PDF Stampa E-mail
Scritto da Marco Tusa   

or summary  for lazy guys on how to use it...

 

I know that a lot has being written around Xtrabackup, and good documentation can be found on the Percona web site.

Anyhow I had to write a summary and clear procedure for my teams, so I choose to share those with all, given it could provide benefit to all community.

 

Each major topic is associate to a checklist, that need to be follow to prevent mistakes.

1. Overview

Xtrabackup is a hot backup tool, that allow you to perform backup on InnoDB with very limited impact on the running transactions/operations.
In order to do this xtrabackup, copy the IBD files AND it takes information out from the REDO log, from a starting point X.
This information needs to be then apply to the datafiles, before restarting the MySQL server on restore.
In short the Backup operation is compose by 2 main phases:
  1. Copy of the file
  2. Copy of the delta modified from REDO log.
Another phase is the "prepare" phase where the REDO log modifications, must apply.
This phase can be done as soon as the backup is complete, if the files are not STREAM (we will see it later), or must be done on Restore if STREAM was use.
Xtrabackup is compose by two main parts, the innobackupex script wrapper, and the xtrabackup.
the Xtrabackup binary has three different version:
- xtrabackup
- xtrabackup_51
- xtrabackup_55
Binary change in respect to the mysql binary version and are automatically selected from innobackupex as follow:
MySQL 5.0.* - xtrabackup_51
MySQL 5.1.* - xtrabackup_51
MySQL 5.1.* with InnoDB plugin - xtrabackup
Percona Server >= 11.0 - xtrabackup
MySQL 5.5.* - xtrabackup_55
It is important to note that while the backup of InnoDB tables is taken with minimal impact, the backup of MyISAM still require a full tables lock.
The full process can be describe as follow:
  1. check connection to MySQL
  2. start the xtrabackup as child process
  3. wait untill xtrabackup suspend the process
  4. connect to mysql
  5. if sever is a slave wait for replication to catch-up
  6. if server is a master it returns right away
  7. flush tables and acquire a read lock (unless explicitly ask in the settings to DO NOT get lock)
  8. write slave information
  9. perform physical write of the files
  10. resume xtrabackup process
  11. unlock tables
  12. close connection to mysql
  13. copy last LRU information
  14. write backup status report

2. User and Grants

Backup user SHOULD not be a common user or a DBA user but it should be one created for this operation as below:
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CREATE USER 'backup'@'localhost' IDENTIFIED BY 'bckuser123';
REVOKE ALL PRIVILEGES, GRANT OPTION FROM 'backup'@'localhost';
GRANT RELOAD, LOCK TABLES, REPLICATION CLIENT ON *.* TO 'backup'@'localhost';
FLUSH PRIVILEGES;
 

 

3. How to invoke the Xtrabackup in standard easy way.

This is the easier way to take a FULL backup using Xtrabackup.

/usr/bin/innobackupex-1.5.1 --defaults-file=<path> --slave-info --user=<username> --password=<secret>   /path/to/destination/backup/folder

ie

/usr/bin/innobackupex-1.5.1 --defaults-file=/home/mysql/instances/mtest1/my.cnf --slave-info --user=backup --password=bckuser123   /home/mysql/backup/

This will produce a full uncompress backup.
root@mysqlt3:/home/mysql/backup/2012_12_21_1300/2012-12-21_14-32-02# ll
total 200088
drwxr-xr-x 15 root root      4096 Dec 21 14:41 ./
drwxr-xr-x  3 root root      4096 Dec 21 14:46 ../
-rw-r--r--  1 root root       263 Dec 21 14:32 backup-my.cnf
-rw-r-----  1 root root 104857600 Dec 21 14:32 ibdata1
drwxr-xr-x  2 root root      4096 Dec 21 14:41 mysql/
drwxr-xr-x  2 root root      4096 Dec 21 14:41 performance_schema/
drwx------  2 root root      4096 Dec 21 14:41 security/
drwx------  2 root root      4096 Dec 21 14:41 test/
drwx------  2 root root      4096 Dec 21 14:41 test_audit/
drwx------  2 root root      4096 Dec 21 14:41 timstaging/
drwx------  2 root root      4096 Dec 21 14:41 timtags/
drwxr-xr-x  2 root root      4096 Dec 21 14:41 world/
-rw-r--r--  1 root root        13 Dec 21 14:41 xtrabackup_binary
-rw-r--r--  1 root root        26 Dec 21 14:41 xtrabackup_binlog_info
-rw-r-----  1 root root        85 Dec 21 14:41 xtrabackup_checkpoints
-rw-r-----  1 root root  99912192 Dec 21 14:41 xtrabackup_logfile
-rw-r--r--  1 root root        53 Dec 21 14:41 xtrabackup_slave_info
backup-my.cnf <--------------- very essential version of the my.cnf with innodb information
ibdata1<---------------------- Main tablespace
mysql/ <----------------------
world/<----------------------- DBs ... with files copy in
xtrabackup_binary <----------- contains the name of the xtrabackup binary used
xtrabackup_binlog_info <------ Binary log information (name/position)
xtrabackup_checkpoints <------ Information regarding the LSN position and range
xtrabackup_logfile <---------- File containing the delta of the modifications
xtrabackup_slave_info <------- Slave information (if slave)
 

 

In this case given it is NOT using streaming and it is not compress, you can prepare the file right away:

innobackupex --use-memory=1G --apply-log /home/mysql/backup/2012_12_21_1300/2012-12-21_14-32-02

 

After few operations you will see:
121221 15:57:04  InnoDB: Waiting for the background threads to start
121221 15:57:05 Percona XtraDB (http://www.percona.com) 1.1.8-20.1 started; log sequence number 30312932364

 

[notice (again)]
If you use binary log and don't use any hack of group commit,
the binary log position seems to be:
InnoDB: Last MySQL binlog file position 0 213145807, file name /home/mysql/instances/mtest1/binlog.000011
xtrabackup: starting shutdown with innodb_fast_shutdown = 1
121221 15:57:05  InnoDB: Starting shutdown...
121221 15:57:09  InnoDB: Shutdown completed; log sequence number 30312932364
121221 15:57:09  innobackupex: completed OK!

 

When done the files needs to be put back in the right place:

innobackupex --defaults-file=/home/mysql/instances/mtest1/my.cnf --copy-back `pwd`

 

Note be sure that destination is empty both DATA and IB_LOGS.
If you can just rename the directories, and create new ones.
When copy is over:
innobackupex: Starting to copy InnoDB system tablespace
innobackupex: in '/home/mysql/backup/2012_12_21_1300/2012-12-21_14-32-02'
innobackupex: back to original InnoDB data directory '/home/mysql/instances/mtest1/data'
innobackupex: Copying '/home/mysql/backup/2012_12_21_1300/2012-12-21_14-32-02/ibdata1' to '/home/mysql/instances/mtest1/data/ibdata1'
innobackupex: Starting to copy InnoDB log files
innobackupex: in '/home/mysql/backup/2012_12_21_1300/2012-12-21_14-32-02'
innobackupex: back to original InnoDB log directory '/home/mysql/logs/mtest1/innodblog'
innobackupex: Finished copying back files.
121221 16:41:38  innobackupex: completed OK!

 

Modify the permission on the data directory:

chown -R mysql:mysql /home/mysql/instances/mtest1;

 

Then restart MySQL, you will see that mysql will recreate the iblogs as well, given we have removed them but this is ok because we have already apply all the changes.
121221 16:44:08 mysqld_safe Starting mysqld daemon with databases from /home/mysql/instances/mtest1/data
121221 16:44:09 [Note] Plugin 'FEDERATED' is disabled.
121221 16:44:09 InnoDB: The InnoDB memory heap is disabled
121221 16:44:09 InnoDB: Mutexes and rw_locks use InnoDB's own implementation
121221 16:44:09 InnoDB: Compressed tables use zlib 1.2.3
121221 16:44:09 InnoDB: Using Linux native AIO
121221 16:44:09 InnoDB: Initializing buffer pool, size = 1.0G
121221 16:44:09 InnoDB: Completed initialization of buffer pool
121221 16:44:09  InnoDB: Log file /home/mysql/logs/mtest1/innodblog/ib_logfile0 did not exist: new to be created
InnoDB: Setting log file /home/mysql/logs/mtest1/innodblog/ib_logfile0 size to 100 MB
InnoDB: Database physically writes the file full: wait...
InnoDB: Progress in MB: 100
...
121221 16:44:15 InnoDB: highest supported file format is Barracuda.
InnoDB: The log sequence number in ibdata files does not match
InnoDB: the log sequence number in the ib_logfiles!
121221 16:44:15  InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
InnoDB: Last MySQL binlog file position 0 213145807, file name /home/mysql/instances/mtest1/binlog.000011
121221 16:44:17  InnoDB: Waiting for the background threads to start
21221 16:44:18 InnoDB: 1.1.8 started; log sequence number 30312933388
121221 16:44:18 [Note] Server hostname (bind-address): '0.0.0.0'; port: 3310
121221 16:44:18 [Note]   - '0.0.0.0' resolves to '0.0.0.0';
121221 16:44:18 [Note] Server socket created on IP: '0.0.0.0'.
121221 16:44:18 [Note] Event Scheduler: Loaded 0 events
121221 16:44:18 [Note] /home/mysql/templates/mysql-55p/bin/mysqld: ready for connections.
Version: '5.5.27-log'  socket: '/home/mysql/instances/mtest1/mysql.sock'  port: 3310  MySQL Community Server (GPL)

 

Checking the content we will have all data back:
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+--------------+--------+--------+----------+----------+-----------+----------+
| TABLE_SCHEMA | ENGINE | TABLES | ROWS     | DATA (M) | INDEX (M) | TOTAL(M) |
+--------------+--------+--------+----------+----------+-----------+----------+
| test         | InnoDB |     51 |  9023205 |  5843.14 |   1314.62 |  7157.76 |
| test         | NULL   |     51 |  9023205 |  5843.14 |   1314.62 |  7157.76 |
| test_audit   | InnoDB |      9 |  1211381 |   658.54 |    230.54 |   889.09 |
| test_audit   | NULL   |      9 |  1211381 |   658.54 |    230.54 |   889.09 |
| NULL         | NULL   |     61 | 10234586 |  6501.68 |   1545.17 |  8046.86 |
+--------------+--------+--------+----------+----------+-----------+----------+

7 rows in set (6.92 sec)


 

4. How to BACKUP the Xtrabackup Using compression

One of the pain in backup compression is the compression process, that could take very long time and could be very inefficient.
We have choose to use pigz which is a tool for Parallel Implementation of gzip.
This combine with the --stream option of xtrabackup generate very compact backup files in shorter time.
The only thing to remember is that YOU CANNOT apply the logs on streaming, so you MUST do it after in the Restore phase.
So given our database as before now we have to be sure that pigz is in place:
#pigz --version
pigz 2.1.6

 

If this is returned (or another version) all ok.
Otherwise  you need to install it:

apt-get install pigz (debian)

yum install pigz (centos)

To execute the backup we will just change the last part of our command as follow:

./innobackupex-1.5.1 --defaults-file=/home/mysql/instances/mtest1/my.cnf --slave-info --user=backup --password=bckuser123  --stream=tar ./ | pigz -p4 - > /home/mysql/backup/2012_12_21_1300/full_mtest1.tar.gz

Once the copy is over you will have a file like this:
drwxr-xr-x  3 root root 4.0K Dec 21 17:08 ./
drwxr-xr-x  3 root root 4.0K Dec 21 14:16 ../
drwxr-xr-x 15 root root 4.0K Dec 21 16:31 2012-12-21_14-32-02/
-rw-r--r--  1 root root 737M Dec 21 17:18 full_mtest1.tar.gz <-------------

 

The whole process on a descktop machine takes:
121221 17:09:52  innobackupex-1.5.1: Starting mysql with options:  --defaults-file='/home/mysql/instances/mtest1/my.cnf' --password=xxxxxxxx --user='backup' --unbuffered --
121221 17:18:29  innobackupex-1.5.1: completed OK!

 

Less then 10 minutes for 8GB data, not excellent but it was running on a vere low level machine.
The file is then ready to be archive, or in our case to be copy over the slave for recovery.

5. How to RESTORE using Xtrabackup from stream

Once we have the file on the target machine we have to expand it.
Very important her is to use the  -i option, this because otherwise the blocks of zeros in archive  will be read as EOF (End Of File), and your set of files will be a mess.
So the string will be something like:

tar -i -xzf full_mtest1.tar.gz

Again after the operation we will have:
-rw-r--r-- 1 root root       269 Dec 21 17:10 backup-my.cnf
-rw-rw---- 1 root root 104857600 Dec 21 17:12 ibdata1
drwxr-xr-x 2 root root      4096 Dec 21 17:40 mysql
drwxr-xr-x 2 root root      4096 Dec 21 17:39 performance_schema
drwxr-xr-x 2 root root      4096 Dec 21 17:39 security
drwxr-xr-x 2 root root      4096 Dec 21 17:39 test
drwxr-xr-x 2 root root      4096 Dec 21 17:39 test_audit
drwxr-xr-x 2 root root      4096 Dec 21 17:39 timstaging
drwxr-xr-x 2 root root      4096 Dec 21 17:39 timtags
drwxr-xr-x 2 root root      4096 Dec 21 17:39 world
-rw-r--r-- 1 root root        13 Dec 21 17:18 xtrabackup_binary
-rw-r--r-- 1 root root        26 Dec 21 17:18 xtrabackup_binlog_info
-rw-rw---- 1 root root        85 Dec 21 17:18 xtrabackup_checkpoints
-rw-rw---- 1 root root 282056704 Dec 21 17:18 xtrabackup_logfile
-rw-r--r-- 1 root root        53 Dec 21 17:18 xtrabackup_slave_info

 

Note this time the information about the binary logs will be CRUCIAL.
Move or delete the old data directory and ib_log.
We have to apply the logs so assuming we have our file set in /home/mysql/recovery:

innobackupex --use-memory=1G --apply-log /home/mysql/recovery

 

Check CAREFULLY the ouput of the process if everithing is fine you will have something like this:
121221 17:52:17  InnoDB: Starting shutdown...
121221 17:52:21  InnoDB: Shutdown completed; log sequence number 30595333132
121221 17:52:21  innobackupex: completed OK!
 

 

Otherwise you must investigate, the most common issues are:
  • forgot -i in the expand
  • space on disk
When copy is over:
121221 18:04:48  innobackupex: completed OK!

 

Change the permissions

chown -R mysql:mysql /home/mysql/instances/mtestslave

 

Start the mysql server.
Again check the mysql error log:
121221 18:06:38 mysqld_safe Starting mysqld daemon with databases from /home/mysql/instances/mtestslave/data
121221 18:06:39 [Note] Plugin 'FEDERATED' is disabled.
121221 18:06:39 InnoDB: The InnoDB memory heap is disabled
121221 18:06:39 InnoDB: Mutexes and rw_locks use InnoDB's own implementation
121221 18:06:39 InnoDB: Compressed tables use zlib 1.2.3
121221 18:06:39 InnoDB: Using Linux native AIO
121221 18:06:39 InnoDB: Initializing buffer pool, size = 1.0G
121221 18:06:39 InnoDB: Completed initialization of buffer pool
121221 18:06:39  InnoDB: Log file /home/mysql/logs/mtestslave/innodblog/ib_logfile0 did not exist: new to be created
InnoDB: Setting log file /home/mysql/logs/mtestslave/innodblog/ib_logfile0 size to 10 MB
InnoDB: Database physically writes the file full: wait...
121221 18:06:40 InnoDB: highest supported file format is Barracuda.
InnoDB: The log sequence number in ibdata files does not match
InnoDB: the log sequence number in the ib_logfiles!
121221 18:06:40  InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
InnoDB: Last MySQL binlog file position 0 150497896, file name /home/mysql/instances/mtest1/binlog.000001
121221 18:06:42  InnoDB: Waiting for the background threads to start
121221 18:06:43 InnoDB: 1.1.8 started; log sequence number 30595333644
121221 18:06:43 [Note] Server hostname (bind-address): '0.0.0.0'; port: 3311
121221 18:06:43 [Note]   - '0.0.0.0' resolves to '0.0.0.0';
121221 18:06:43 [Note] Server socket created on IP: '0.0.0.0'.
121221 18:06:43 [Note] Event Scheduler: Loaded 0 events
121221 18:06:43 [Note] /home/mysql/templates/mysql-55p/bin/mysqld: ready for connections.
Version: '5.5.27-log'  socket: '/home/mysql/instances/mtestslave/mysql.sock'  port: 3311  MySQL Community Server (GPL)
 

 

And now is time to log in check the data set AND fix replication.
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root@localhost [(none)]> show schemas;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| security           |
| test               |
| test_audit         |
| world              |
+--------------------+
13 rows in set (0.04 sec)
root@localhost [(none)]> SELECT TABLE_SCHEMA, ENGINE, COUNT(1) as 'TABLES', sum(TABLE_ROWS) as 'ROWS',
TRUNCATE(sum(DATA_LENGTH)/pow(1024,2),2) as 'DATA (M)',
TRUNCATE(sum(INDEX_LENGTH)/pow(1024,2),2) as 'INDEX (M)',
TRUNCATE((sum(DATA_LENGTH)+sum(INDEX_LENGTH))/pow(1024,2),2) AS 'TOTAL(M)'
FROM information_schema.tables       WHERE TABLE_SCHEMA <> 'information_schema'
AND TABLE_SCHEMA <> 'mysql'     AND TABLE_SCHEMA not like 'avail%'
AND TABLE_SCHEMA <> 'maatkit'            AND TABLE_TYPE = 'BASE TABLE'
GROUP BY TABLE_SCHEMA, ENGINE      WITH ROLLUP;
+--------------------+--------------------+--------+----------+----------+-----------+----------+
| TABLE_SCHEMA       | ENGINE             | TABLES | ROWS     | DATA (M) | INDEX (M) | TOTAL(M) |
+--------------------+--------------------+--------+----------+----------+-----------+----------+
| performance_schema | PERFORMANCE_SCHEMA |     17 |    23014 |     0.00 |      0.00 |     0.00 |
| performance_schema | NULL               |     17 |    23014 |     0.00 |      0.00 |     0.00 |
| security           | InnoDB             |      1 |  1454967 |   170.73 |     60.75 |   231.48 |
| security           | NULL               |      1 |  1454967 |   170.73 |     60.75 |   231.48 |
| test               | InnoDB             |     51 |  9298913 |  6058.39 |   1347.78 |  7406.17 |
| test               | NULL               |     51 |  9298913 |  6058.39 |   1347.78 |  7406.17 |
| test_audit         | InnoDB             |      9 |  1189343 |   685.56 |    236.56 |   922.12 |
| test_audit         | NULL               |      9 |  1189343 |   685.56 |    236.56 |   922.12 |
| world              | MyISAM             |      3 |     5302 |     0.35 |      0.06 |     0.42 |
| world              | NULL               |      3 |     5302 |     0.35 |      0.06 |     0.42 |
| NULL               | NULL               |    227 | 11971539 |  6916.70 |   1645.74 |  8562.44 |
+--------------------+--------------------+--------+----------+----------+-----------+----------+
 

 

So far so good.
Now is time to modify the slave.
First take the current status:
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root@localhost [(none)]> SHOW slave STATUS\G
Empty SET (0.00 sec)
root@localhost [(none)]>

 

Ok nothing, good.
Assign the master AND the log file and position from xtrabackup_binlog_info.
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cat xtrabackup_binlog_info
binlog.000001    150497896

 

Prepare the command as:

change master to master_host='192.168.0.3', master_port=3310,master_user='replica',master_password='xxxx', master_log_file='binlog.000001',master_log_pos=150497896;

Check again:
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root@localhost [(none)]> SHOW slave STATUS\G
*************************** 1. row ***************************
Slave_IO_State:
Master_Host: 192.168.0.3
Master_User: replica
Master_Port: 3310
Connect_Retry: 60
Master_Log_File: binlog.000001
Read_Master_Log_Pos: 150497896
Relay_Log_File: mysql-relay-bin.000001
Relay_Log_Pos: 4
Relay_Master_Log_File: binlog.000001
Slave_IO_Running: No
Slave_SQL_Running: No
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 150497896
Relay_Log_Space: 107
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: NULL
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 0
1 row IN SET (0.00 sec)
root@localhost [(none)]>


Perfect start the slave:

slave start;

AND CHECK again:


root@localhost [(none)]> SHOW slave STATUS\G
*************************** 1. row ***************************
Slave_IO_State: Waiting FOR master TO send event
Master_Host: 192.168.0.3
Master_User: replica
Master_Port: 3310
Connect_Retry: 60
Master_Log_File: binlog.000001
Read_Master_Log_Pos: 206843593
Relay_Log_File: mysql-relay-bin.000002
Relay_Log_Pos: 22872
Relay_Master_Log_File: binlog.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 150520518
Relay_Log_Space: 56346103
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 30
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 3310
1 row IN SET (0.00 sec)

 

Ok we have some delay as expected by all is running as it should.
Our server is up and running.

6. How to do INCREMENTAL BACKUP with Xtrabackup 

 

Incremental backup works in a different way.
To understand it correctly we need to remember that InnoDB pages have a sequence number LSN (Log Sequence Number), given that, each incremental backup starts from the previous stored LSN.

 

Incremental backup must have a first FULL Backup as base, then each following incremental, will be stored in a different directory (by timestamp).

To restore the incremental backup the full set of incremental, from the BASE to the last point in time, need to be apply.
So if we have the Full Backup done on Monday, and incremental are taken every day, if we need to restore the full set on Friday, we must apply the logs on the BASE (Monday) following the chronological order, Monday (base), then Tuesday, Wednesday, Thursday, Friday.

Only at that point we will have the full set of data, that can replace the one we were having on the server.

To remember that this works only for InnoDB, other storage engines like MyISAM are copy in full every time.

6.1. Let this work without compression

/opt/percona-xtrabackup-2.0.4/bin/innobackupex-1.5.1 --defaults-file=/home/mysql/instances/mtest1/my.cnf --slave-info --user=backup --password=bckuser123   /home/mysql/backup/

The new directory 2013-01-10_13-07-24 is the BASE.

Checking the files inside we can check the LSN position:
root@tusacentral03:/home/mysql/backup/2013-01-10_13-07-24# cat xtrabackup_checkpoints
backup_type = full-backuped
from_lsn = 0
to_lsn = 32473279827
last_lsn = 32473279827
Last LSN is 32473279827

 

As exercise let us do TWO incremental backup starting from this base, but first add some data...
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root@localhost [test]> SHOW processlist;
+-----+--------+---------------------------+------+---------+------+--------+------------------------------------------------------------------------------------------------------+
| Id  | User   | Host                      | db   | Command | Time | State  | Info                                                                                                 |
+-----+--------+---------------------------+------+---------+------+--------+------------------------------------------------------------------------------------------------------+
|  87 | root   | localhost                 | test | Query   |    0 | NULL   | SHOW processlist                                                                                     |
|  92 | stress | tusacentral01.LOCAL:37293 | test | Sleep   |    0 |        | NULL                                                                                                 |
|  94 | stress | tusacentral01.LOCAL:37296 | test | Query   |    0 | UPDATE | INSERT INTO tbtest30 (uuid,a,b,c,counter,partitionid,strrecordtype) VALUES(UUID(),731188002,"hd rsg  |
|  95 | root   | localhost:37295           | test | Query   |    0 | update | INSERT INTO test_audit.tbtest4 values(NEW.autoInc,NEW.a,NEW.uuid,NEW.b,NEW.c,NEW.counter,NEW.time,NE |
|  96 | stress | tusacentral01.local:37298 | test | Query   |    0 | NULL   | COMMIT                                                                                               |
|  97 | root   | localhost:37299           | test | Query   |    0 | update | INSERT INTO test_audit.tbtest4 values(NEW.autoInc,NEW.a,NEW.uuid,NEW.b,NEW.c,NEW.counter,NEW.time,NE |
|  98 | stress | tusacentral01.local:37300 | test | Query   |    0 | update | insert INTO tbtest15 (uuid,a,b,c,counter,partitionid,strrecordtype) VALUES(UUID(),598854171,"usfcrgl |
|  99 | root   | localhost:37301           | test | Query   |    0 | UPDATE | INSERT INTO test_audit.tbtest4 VALUES(NEW.autoInc,NEW.a,NEW.uuid,NEW.b,NEW.c,NEW.counter,NEW.time,NE |
| 100 | stress | tusacentral01.LOCAL:37302 | test | Query   |    0 | UPDATE | INSERT INTO tbtest15 (uuid,a,b,c,counter,partitionid,strrecordtype) VALUES(UUID(),22723485,"vno ehhr |
| 101 | stress | tusacentral01.local:37303 | test | Query   |    0 | update | insert INTO tbtest1 (uuid,a,b,c,counter,partitionid,strrecordtype) VALUES(UUID(),991063177,"nqdcogeu |
| 102 | stress | tusacentral01.LOCAL:37304 | test | Query   |    0 | UPDATE | INSERT INTO tbtest1 (uuid,a,b,c,counter,partitionid,strrecordtype) VALUES(UUID(),86481207,"sdfabnogn |
| 103 | stress | tusacentral01.local:37305 | test | Query   |    0 | NULL   | COMMIT                                                                                               |
+-----+--------+---------------------------+------+---------+------+--------+------------------------------------------------------------------------------------------------------+
12 rows in set (0.00 sec)

 

Now let us create the first incremental backup:

/opt/percona-xtrabackup-2.0.4/bin/innobackupex-1.5.1 --incremental --incremental-basedir=/home/mysql/backup/2013-01-10_13-07-24 --defaults-file=/home/mysql/instances/mtest1/my.cnf --slave-info --user=backup --password=bckuser123   /home/mysql/backup/

 

After all the process is complete, we will have TWO directories:
total 20
drwxr-xr-x  5 root  root  4096 Jan 10 13:30 ./
drwxr-xr-x 18 mysql mysql 4096 Dec 28 12:16 ../
drwxr-xr-x 15 root  root  4096 Jan 10 13:17 2013-01-10_13-07-24/
drwxr-xr-x 15 root  root  4096 Jan 10 13:34 2013-01-10_13-30-43/ <-------- the last one is the Incremental
 

 

I was inserting data mainly on the TEST schema, and as you can see test is the one that HAS more data in, which represent the DELTA:
root@tusacentral03:/home/mysql/backup/2013-01-10_13-30-43# du -sh *
4.0K    backup-my.cnf
4.5M    ibdata1.delta
4.0K    ibdata1.meta
1.5M    mysql
212K    performance_schema
18M        security <---------------------------------
1.2G    test <---------------------------------
173M    test_audit <---------------------------
488K    world
4.0K    xtrabackup_binary
4.0K    xtrabackup_binlog_info
4.0K    xtrabackup_checkpoints
4.0K    xtrabackup_logfile
4.0K    xtrabackup_slave_info
 

 

On top of the usual files, in the schema directory and per table I will find some additional inormations inside the tablexyz.ibd.meta file
root@tusacentral03:/home/mysql/backup/2013-01-10_13-30-43/test# cat tbtest1.ibd.meta
page_size = 16384
zip_size = 0
space_id = 1983

 

Checking the file xtrabackup_checkpoints you will see the delta related to LSN
root@tusacentral03:/home/mysql/backup/2013-01-10_13-30-43# cat xtrabackup_checkpoints
backup_type = incremental
from_lsn = 32473279827 <------------ starting point
to_lsn = 33215076229   <------------ End point
last_lsn = 33215076229

 

Let us add other data and take another incremeental.
root@tusacentral03:/opt/percona-xtrabackup-2.0.4/bin# /opt/percona-xtrabackup-2.0.4/bin/innobackupex-1.5.1 --incremental \
--incremental-basedir=/home/mysql/backup/2013-01-10_13-30-43/ \
--defaults-file=/home/mysql/instances/mtest1/my.cnf  \
--slave-info --user=backup --password=bckuser123   /home/mysql/backup/

 

There is a HUGE difference from the previous command, the BASEDIR change, and must be the las incremental.
Given this is not always possible it is good practices when working with scripts to store the LAST LSN in the xtrabackup_checkpoints and pass it as parameter with:

--incremental-lsn=xyz

This is the more elegant and flexible way.

Ok NOW we have 3 Directory:
drwxr-xr-x 15 root  root  4096 Jan 10 13:17 2013-01-10_13-07-24/
drwxr-xr-x 15 root  root  4096 Jan 10 13:34 2013-01-10_13-30-43/ <--------- First incremental
drwxr-xr-x 15 root  root  4096 Jan 10 14:02 2013-01-10_13-57-04/ <--------- Second incremental

 

To have a full backup we have now to rebuild the set from the BASE then First incremental then Second Incremental, to do so we need to apply the changes but NOT the rollback operation.
If we forgot and perform ALSO the rollback, we will not be able to continue applying the incremental backups.
To do so there are two ways, explicit and implicit:
  • Explicit --apply-log --redo-only
  • Implicit --apply-log-only
I like the Explicit because you know exactly what you pass also if this can be more verbose, so my commands will be:

/opt/percona-xtrabackup-2.0.4/bin/innobackupex-1.5.1 --use-memory=1G --apply-log --redo-only /home/mysql/restore/2013-01-10_13-07-24

/opt/percona-xtrabackup-2.0.4/bin/innobackupex-1.5.1 --use-memory=1G --apply-log --redo-only /home/mysql/restore/2013-01-10_13-07-24 --incremental-dir=/home/mysql/restore/2013-01-10_13-30-43

/opt/percona-xtrabackup-2.0.4/bin/innobackupex-1.5.1 --use-memory=1G --apply-log --redo-only /home/mysql/restore/2013-01-10_13-07-24 --incremental-dir=/home/mysql/restore/2013-01-10_13-57-04

Once done the BASE directory will contains the up to date information including the binary log position:
root@tusacentral03:/home/mysql/restore/2013-01-10_13-07-24# cat xtrabackup_binlog_info
binlog.000005    275195253     <------------ Original from Base
root@tusacentral03:/home/mysql/restore/2013-01-10_13-07-24# cat ../../backup/2013-01-10_13-07-24/xtrabackup_binlog_info
binlog.000003    322056528     <------------ Up to date from incremental
 

 

It is now time to have all finalize it:

/opt/percona-xtrabackup-2.0.4/bin/innobackupex-1.5.1 --use-memory=1G --apply-log /home/mysql/restore/2013-01-10_13-07-24

 

At this point we just need to copy back on the slave the content of BASE directory /home/mysql/restore/2013-01-10_13-07-24, and change the permissions.
[root@tusacentral07 data]# scp -R 
 Questo indirizzo e-mail è protetto dallo spam bot. Abilita Javascript per vederlo.
 .0.3:/home/mysql/restore/2013-01-10_13-07-24/*  .
[root@tusacentral07 data]# sudo chown -R mysql:mysql .
 

 

At this point if this is a slave we just to setup the replication from the last binlog and positon as usual, otherwise all done and we can restart the server.

 

6.2. Incremental with compression

To perform the incremental + compression the process is the same but instead tar we need to use xbstream, for documentation I have add the --incremental-lsn with the value from the latest backup,
at this point add some data, and take the backup again.
Given I don't have the previous set of FULL + Incremental1 + Incremental2 UNPREPARED, I will take again 1 full and to compress incremental.

/opt/percona-xtrabackup-2.0.4/bin/innobackupex-1.5.1 --incremental\

--incremental-lsn=34020868857 \

--defaults-file=/home/mysql/instances/mtest1/my.cnf \

 --slave-info --user=backup --password=bckuser123 \

 --extra-lsndir=/home/mysql/backup/ \

--stream=xbstream --parallel=4 ./ |pigz -p4 - > /home/mysql/backup/incremental_2013_01_10_19_05.gz

To note is the parameter  --extra-lsndir which allow you to specify an additional location for the LSN file position,
this is very important because it needs to be "grep" for the next incremental backup.
Like:
grep last_lsn xtrabackup_checkpoints|awk -F' = ' '{print $2}'
34925032837

 

and the parameter --parallel=4 to implement multi thread streaming
So next will be:
/opt/percona-xtrabackup-2.0.4/bin/innobackupex-1.5.1 --incremental \
--incremental-lsn=34925032837 \
--defaults-file=/home/mysql/instances/mtest1/my.cnf \
--slave-info --user=backup --password=bckuser123 \
--extra-lsndir=/home/mysql/backup/ \
--stream=xbstream 

--parallel=4 ./ |pigz -p4 - > /home/mysql/backup/incremental_2013_01_11_11_35.gz

 

Once done taking again the LSN value it will be 35209627102
At this point we have a compress incremental backup using xbstream and pigz.
Point is can we restore it correctly?
copy all the files to the resore area/server
root@tusacentral03:/home/mysql/backup# ll
total 631952
drwxr-xr-x  3 root  root       4096 Jan 11 11:36 ./
drwxr-xr-x 19 mysql mysql      4096 Jan 10 15:01 ../
drwxr-xr-x 15 root  root       4096 Jan 10 17:27 full_2013_01_10_18_54.gz
-rw-r--r--  1 root  root  360874358 Jan 11 11:25 incremental_2013_01_10_19_05.gz
-rw-r--r--  1 root  root  286216063 Jan 11 11:41 incremental_2013_01_11_11_35.gz
-rw-r--r--  1 root  root         93 Jan 11 11:41 xtrabackup_checkpoints
 

 

then to expand it:

pigz -d -c full_2013_01_10_18_54.gz | xbstream -x -v

create 2 directory:

mkdir 2013_01_10_19_05

mkdir 2013_01_11_11_35

Then

pigz -d -c incremental_2013_01_10_19_05.gz | xbstream -x -v

pigz -d -c incremental_2013_01_11_11_35.gz | xbstream -x -v

 

After that the procedure will be the same.

/opt/percona-xtrabackup-2.0.4/bin/innobackupex-1.5.1 --use-memory=1G --apply-log --redo-only /home/mysql/restore/2013-01-10_17-15-27

/opt/percona-xtrabackup-2.0.4/bin/innobackupex-1.5.1 --use-memory=1G --apply-log --redo-only /home/mysql/restore/2013-01-10_17-15-27 --incremental-dir=/home/mysql/restore/2013_01_10_19_05

/opt/percona-xtrabackup-2.0.4/bin/innobackupex-1.5.1 --use-memory=1G --apply-log --redo-only /home/mysql/restore/2013-01-10_17-15-27 --incremental-dir=/home/mysql/restore/2013_01_11_11_35

 

Finalize the process

/opt/percona-xtrabackup-2.0.4/bin/innobackupex-1.5.1 --use-memory=1G --apply-log /home/mysql/restore/2013-01-10_17-15-27

 

Copy in the production location:
To remove possible not needed files :

find . -name "*.TR*" -exec  \rm -v '{}' \;

 

Assign correct grants to mysql user

chown -R mysql:mysql data

restart and if slave set the right binlog and position as before
Done!

 

7. Incremental with compression and NetCat

There are two possible ways to perform the copy with NetCat:
  • one is "on the fly" means that the stream instead being direct to a local file it is directly push on the "Recovery" server.
  • the other is to write the file then push it to the "Recovery" server.
Using the the "on the fly" is in my opinion conceptually dangerous.
This because a backup operation should be as more solid as possible.
Having the stream directed to the final server is opening to possible issue at any network glitch.
Any network flotation could affect the whole backup, and there could be also possible scenario where a full transmitted backup will result corrupted.
This because IF a network issue happen during the transfer the process on the source or destination server, the one DOING the backup or the one receiving can crash or hung.
All the above impose a sanity check on the process and on the final result, to be sure that in case of failure the backup will be take again, or at least there will be awareness about the issue.

 

Needs to be say that the process is not so fragile when dealing with small amount of data, but it could become much more concerning when dealing with Gigs because resource allocation limit on the source machine.

The NetCat solution see two elements in our case:

  • server (sender)
  • client (receiver)
This is valid in our case but needs mention that the server can also get input from the client, but this is not a topic here.

7.1. The on the fly

The backup process is suppose to be launched on the server with the following statement:
/opt/percona-xtrabackup-2.0.4/bin/innobackupex-1.5.1 --incremental  --incremental-lsn=35209627102 --defaults-file=/home/mysql/instances/mtest1/my.cnf --slave-info --user=backup --password=bckuser123 --extra-lsndir=/home/mysql/backup/ --stream=xbstream --parallel=4 ./ |pigz -p4 - | nc -l 6666
while on client :
nc 192.168.0.3 6666|pv -trb > /home/mysql/recovery/incremental_2013_01_14_12_05.gz
So the only difference is the add of the NetCat commands and obviously the need to have it done on the client.
Once the process is over, the expand can be done as usual:
pigz -d -c incremental_2013_01_14_12_05.gz | xbstream -x -v

7.2. Two steps process

Is exactly the same of the one "Incremental with compression", but instead doing a file copy issue the commands:
on the server:
cat /home/mysql/backup/incremental_2013_01_14_12_05.gz | nc -l 6666| pv -rtb
On the client:
nc 192.168.0.3 6666|pv -trb > /home/mysql/recovery/incremental_2013_01_14_12_05.gz

7.3. Conclusion

I think it could make sense to use NetCat ONLY in very specific cases, and only developing solid scripts around it, including in them:
  • status checks of the backup operation
  • list of the transmitted files
  • LSN position validation
  • network status/monitor during the operations
In short a possible nightmare.

8. Check lists

8.1. Simple backup

[] Check binary version
[] Check binaries are accessible in the PATH and accessible
[] Assign correct user/password in MySQL for backup user
[] Create or check backup data destination folder
[] Check my.cnf for datadir and be sure is pointing in the right place
[] Execute backup
[] Apply logs

8.2. Simple restore

[] be sure mysql server is down
[] remove / move data from original directory
[] remove / move ib_logs from original directory
[] run innobackupex --copy-back
[] check file permissions for mysql
[] start mysql
[] check the mysql log for error
[] log in and check for data.

8.3. Backup with Stream and compression

[] Check binary version
[] Check binaries are accessible in the PATH and accessible
[] Assign correct user/password in MySQL for backup user
[] Create or check backup data destination folder
[] Check my.cnf for datadir and be sure is pointing in the right place
[] Check for Pigz presence and version
[] Execute backup

8.4. Restore from Stream on a different machines (slave)

[] be sure mysql server is down
[] remove / move data from original directory
[] remove / move ib_logs from original directory
[] copy over the compress file
[] expand the backup in a safe directory
[] run innobackupex --copy-back
[] check file permissions for mysql
[] check that server WILL NOT restart the slave process on start
[] start mysql
[] check the mysql log for error
[] log in and check for data.
[] take the master log position
[] check for slave process information
[] apply new binary log position
[] restart slave
[] check slave status

8.5. Incremental Backup with Stream and compression

[] Check binary version
[] Check binaries are accessible in the PATH and accessible
[] Assign correct user/password in MySQL for backup user
[] Create or check backup data destination folder
[] Check my.cnf for datadir and be sure is pointing in the right place
[] Check for Pigz presence and version
[] Check for LSN file postion in xtrabackup_checkpoints
[] Assign the LSN to the "incremental-lsn" parameter
[] Be sure that the --extra-lsndir parametr is present and pointing to an existing directory
[] Execute backup

8.6. Incremental Restore from Stream on a different machines or slave

[] be sure mysql server is down
[] remove / move data from original directory
[] remove / move ib_logs from original directory
[] copy over the compress files
[] validate the chronological order from the BASE to the last increment
{loop for each file set}
[] expand the backup in a safe directory one a time
[] be sure that you apply log with "--apply-log --redo-only" parameters every time
[] be sure you always have the correct destination directory set (BASE set)
[] remove the incremental once apply
{loop end}
[] run innobackupex --apply-log on the BASE set
[] remove IB_log files
[] copy files to destination directory
[] check file permissions for mysql
[] check that server WILL NOT restart the slave process on start
[] start mysql
[] check the mysql log for error
[] log in and check for data.
[] take the master log position
[] check for slave process information
[] apply new binary log position
[] restart slave
[] check slave status


{joscommentenable}




Commenti (1)
  • Sheeri Cabral  - wow, awesome!
    Great documentation there!

    BTW you mentioned checklists - there's an awesome service called "Checkmarkable" (I'm not affiliated with it at all, just a happy user). It's free (yay!) and it is helpful becaue you can make a checklist template, like the templates you have above. Then someone can instantiate the template, or many people can make many instantiations, each checking things off at their own pace on their own checklist, and without having to print anything. It remembers where you are in the checklist.

    It has greatly reduced ticket updates like "I'm on step 3 now, which is xxxx".
  • Marco Tusa
    Tks Sheeri, will check the tool and if it fits I will start to use ... I have tons of checklists and in the need to produce more ... I guess you know very well why!!
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Ultimo aggiornamento Domenica 18 Agosto 2013 17:23
 
 

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