Tag Archives: MySQL

21 Jan

Debugging Percona Xtradb (Galera) Cluster node startup / SST errors

We were working on setting up Percona XtraDB (Galera) Cluster following the Documentation for version 5.6+. This blog post is a use-case of a debugging / troubleshooting & fixing different SST issues we faced while bringing-up the cluster nodes.

We already have a successfully bootstrapped node-1 and now we’re adding second node (node-2) which was causing following error.

"2015-01-15 17:33:19 24618 [ERROR] WSREP: Process completed with error: wsrep_sst_xtrabackup --role 'joiner' --address '10.10.10.1' --auth 'sstuser:xxx' --datadir '/var/lib/mysql/' --defaults-file '/etc/my.cnf' --parent '24618'  '' : 32 (Broken pipe)
2015-01-15 17:33:19 24618 [ERROR] WSREP: Failed to read uuid:seqno from joiner script.
2015-01-15 17:33:19 24618 [ERROR] WSREP: SST failed: 32 (Broken pipe)
2015-01-15 17:33:19 24618 [ERROR] Aborting"

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31 Dec

MariaDB slave restore using GTID & xtrabackup bug

Recently I happen to work for a MySQL database restore, a pretty exciting task for DBA :P

Well, backup server was already configured with Holland (backup framework) & Xtrabackup (Percona’s backup tool) which made our lives easier with steps to restore.

Extracted backup command from backup server’s holland.log:

/usr/bin/innobackupex-1.5.1 --defaults-file=/mysql_backups/xtrabackup/20141219_013002/my.cnf --stream=tar --tmpdir=/mysql_backups/xtrabackup/20141219_013002 --slave-info --no-timestamp /mysql_backups/xtrabackup/20141219_013002 > /mysql_backups/xtrabackup/20141219_013002/backup.tar.gz 2 > /mysql_backups/xtrabackup/20141219_013002/xtrabackup.log

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27 May

xtrabackup_51: not found & no ‘mysqld’ group in MySQL options

Recently I happen to setup a new MySQL instance with my tools – a standard MySQL 5.1+, xtrabackup setup and last-hotbackup.tar.gz.

To restore from the backup we used xtrabackup binaries and ran into issues following standard commands (assuming no changes):

To prepare the backup I used apply-log as follows:

$] innobackupex-1.5.1 --defaults-file=/usr/local/mysql/data/backup-my.cnf --apply-log  /usr/local/mysql/data --ibbackup xtrabackup_51

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10 Jan

MySQL variable innodb_flush_method – summarized

innodb_flush_method

innodb_flush_method variable specifies how InnoDB opens and flushes log and data files. In Innodb optimization, setting the variable innodb_flush_method tweaks the performance most of the times but there are cases of otherwise though. If innodb_flush_method is set to O_DIRECT it’d avoid double buffering and reduce swap pressure and helps improving performance.
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17 Dec

Is your backup complete? – backup MySQL users privileges / grants – pt-show-grants

Everybody knows the criticality of backup. You might have had your database dumped, data directory copied, flat files exported and even config and binary log files backed-up. But did you backup your MySQL user privileges?

One can easily forget to backup the user privileges but it is much easier to do and you should backup your MySQL server user privileges / grants regularly.

1. Backup MySQL user privileges using mysqldump:

$] mysqldump -uUSER -pPASS --databases mysql > mysql.sql
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-- Kedar Vaijanapurkar --