…. The original idea was to configure them with raid-10 + LVM, making sure to stripe the LV when we need to… btrfs). Let’s review them. Snapshots ZFS does snapshot, like LVM but… since it is a copy on write filesystem, the… can easily run a server with hundreds of snapshots. With LVM, your IO performance drops to 33% after the first snapshot…
Post: Estimating Undo Space needed for LVM Snapshot
June 9, 2008 By 5 Comments
… being remapped it is read from the undo location. The LVM Snapshots versioning is however different from database Multi Versioning because… overhead, and there is no space requirements. Another issue with LVM snapshot it may convert pretty much sequential IO done while… recreation etc are also possible trouble makers. Third,Use dedicated LVM volume for MySQL Instance. This is good idea for many…
Post: Disaster: LVM Performance in Snapshot Mode
February 5, 2009 By 55 Comments
… bottleneck. This is exactly the case with LVM Number of customers have reported the LVM gives very high penalty when snapshots are… any system doing writes to experience the “performance shock” when LVM snapshot is created with greatly reduced capacity which when will… (in particular sequential file reads). If you’ve done some LVM performance tests yourself or will be repeating mine (parameters posted…
Post: SSD, XFS, LVM, fsync, write cache, barrier and lost transactions
March 2, 2009 By 32 Comments
… bad, we have no good replacement yet) and I tried LVM under XFS. With write-cache ON and default mount options…. with barrier) I have 5250 writes / s, this is because LVM ignores write barriers (see http://dammit.lt/2008/11/03… is good ones – another are for research 4. XFS without LVM is putting barrier option which decreases write performance a lot
Post: LVM Configuration mistake to Avoid
July 9, 2008 By 10 Comments
One of our customers was setting up box for MySQL LVM backups. The box had 2 RAID volumes (internal drives and… volumes were configured as different “volume groups”. Volume groups in LVM live completely isolated life and you can’t use space….S That would be interested to benchmark one day how LVM performs in shapshot mode in case undo space is stored…
Post: Using LVM for MySQL Backup and Replication Setup
August 21, 2006 By 53 Comments
… Backup advice my first question would be if they have LVM installed or have some systems with similar features set for… snapshot of many volumes. Lets speak a bit about how LVM and snapshotting in general works. Really there are different implementations… of the volume at the time storage is created. In LVM it is implementeed as copy on write. Special storage area…
Comment: Disaster: LVM Performance in Snapshot Mode
February 6, 2009 By 55 Comments
… files (<16k) creation, no much difference; For large files creation, LVM causes the speed drops from 1300000 to 900000. Random Read… files (<16k) creation, no much difference; For large files creation, LVM causes the speed drops from 3000000 to 2000000. After a…, compared to 9000 qps insert from previous RAID 10 without LVM (Dell poweredge, database size 600G). We scaled out the database…
Post: Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 13 Comments
… option however, the effect disappeared and performance without LVM was slightly better than with LVM as expected. I had to redo all… file system properly aligned; sunit/swidth set during mkfs. No LVM at this point. 5. Partition table aligned properly; sunit/swidth…. Neither IO alignment nor file size made any difference. Adding LVM here reduced single-thread performance by 5-10%. Sequential write…
Post: Aligning IO on a hard disk RAID – the Theory
June 9, 2011 By 18 Comments
… point. Let’s get down one more level: LVM If you are using LVM, you want to make sure it does not… 256k RAID stripe elements, I would have ended up with LVM physical extent starting somewhere in the middle of the stripe… in the process when using pvcreate to initialize disk for LVM use, the two options you are interested in are –dataalignment…
Post: Faster Point In Time Recovery with LVM2 Snaphots and Binary Logs
February 23, 2012 By 3 Comments
… assumes that you already have a decent know how of LVM and snaphots and using LVM2 >= 2.02.58 (January 2010… before the first DELETE statement above. If you use my LVM snapshot script*, it also saves the binary log coordinates when… somehow blew up in flames, hardware problems or encounter and LVM bug, your snapshots are useless. Also, you cannot test restore…
