quick question – the xfs_freeze feature is really killer when one wants to do consistent snapshots/backup of database directories, etc. Is there anything similar in ext4 or is the benchmark of ext4 +lvm (which I know allows this) on par with xfs_freeze (without lvm) ?
Comment: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 24, 2012 By 20 Comments
… LVM snapshot implemented? Is it not atomic in itself, so that InnoDB file writes can happen while the snapshot it being made? If LVM snapshots are atomic, yet a FTWRL InnoDB snapshot can be inconsistent and unrecoverable…
Comment: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 24, 2012 By 20 Comments
…, What do you mean by “snapshot what is recoverable”. Even without Flush tables with read lock, LVM snapshot should be recoverable 100% of… there have been very few of them. Typically problems with LVM snapshots can originate from either not having log files and data… the same partition or synchronization of binary log and innodb snapshot. In certain versions FLUSH TABLES WITH READ LOCK would not…
Post: Estimating Undo Space needed for LVM Snapshot
June 9, 2008 By 5 Comments
…. When snapshot is being read if the block is being remapped it is read from the undo location. The LVM Snapshots versioning is however different from database Multi Versioning because only one old version per snapshot is needed while… overhead, and there is no space requirements. Another issue with LVM snapshot it may convert pretty much sequential IO done while scanning…
Post: Disaster: LVM Performance in Snapshot Mode
February 5, 2009 By 55 Comments
… The performance without LVM snapshot was 159 io/sec which is quite expected for single thread and no BBU. With LVM snapshot enabled the performance was 25 io/sec which is about 6 times lower ! I honestly do not understand what LVM could… this run I got approximately 200 ios/sec without LVM snapshot enabled while with snapshot I got: 33.20 Requests/sec executed 46…
Post: Faster Point In Time Recovery with LVM2 Snaphots and Binary Logs
February 23, 2012 By Leave a Comment
LVM snapshots is one powerful way of taking a consistent backup of … above. If you use my LVM snapshot script*, it also saves the binary log coordinates when the snapshot was taken and saves it…, hardware problems or encounter and LVM bug, your snapshots are useless. Also, you cannot test restore your snapshots – they are one time use…
Post: Using LVM for MySQL Backup and Replication Setup
August 21, 2006 By 53 Comments
… be able to do atomic snapshot of many volumes. Lets speak a bit about how LVM and snapshotting in general works. Really there… do journal recovery on snapshot. With read-only snapshot you need to make sure filesystem synchronizes device before snapshot is taken so no…’ll need to point your MySQL Slaves created from this snapshot. 4) Snapshot created, now you want to let MySQL Server to…
Comment: Using LVM for MySQL Backup and Replication Setup
August 18, 2011 By 53 Comments
… , Following this blog we arrived at the conclusion to use lvm snapshots on the slave servers to prevent slaves from being used… to pursue other avenues like lvm snapshot . So i can easily lock the mysql tables and take a lvm snapshot with lvcreate in a quick seconds and then release the mysql lock . Now that I have the snapshot of…
Comment: Disaster: LVM Performance in Snapshot Mode
February 9, 2009 By 55 Comments
… file systems (WAFL, ZFS). With log structured filesystems you get snapshots practically for free but there are other disadvantages like fragmentation… on various levels – volume manager (LVM, VXVM) or in the filesystem (VxFS). If you use LVM snapshots the choice of the filesystem can… ext3 filesystem and compared it with xfs. The difference with LVM snapshot is big. “randomio” opens its target with O_DIRECT and…
Post: How to Monitor MySQL with Percona's Nagios Plugins
February 22, 2012 By 8 Comments
… full LVM snapshots. LVM backup strategies can fail to delete snapshots after finishing, sometimes due to the backup script failing before completion. Additionally, LVM snapshots that don’t have enough copy-on-write space can fail before the backup completes. The pmp-check-lvm-snapshots plugin…
