… have single running query. Though this one is specific to write requests – if you have some reporting queries to deal with… complete before continuing. Though in decent systems you have battery backed up cache so this wait is not long. In case innodb… used RAID level for write intensive database systems, you will have 2 hard drives to pick reading any block. RAID controller (and even software RAID…
Comment: Evaluating IO subsystem performance for MySQL Needs
March 5, 2008 By 23 Comments
… six disk RAID-10 15K RPM system, 22 MB/sec of random reads in a mixed read/write setup is just as good as it gets, the biggest win I receive from the battery backed cache is knowing that the last IO-OP from the controller made it to the…
Comment: How much overhead DRDB could cause ?
June 3, 2008 By 4 Comments
… a RAID controller with battery-backed write cache to the setup (and you should), your local I/O latency decreases dramatically. Now your local writes “complete… probably not notice much of this. However, for extremely high write loads, DRBD currently does add comparatively large performance penalties percentage…
Comment: Beware: ext3 and sync-binlog do not play well together
April 7, 2009 By 19 Comments
Thanks for your quick replies. I am running MySQL on a Dell PowerEdge 2950 with PERC6 (with BBU) 6 x 15K drives configured with Raid 10. Is the recommendation to: 1) mount XFS with -onobarrier 2) write cache disabled for the drive 3) write-back enabled for the controller
Comment: Online MySQL Configuration Wizard from Percona
January 3, 2012 By 24 Comments
… you do not have adequate hardware (a good quality RAID controller with a battery-backed write cache, for example), then you might need to relax…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 19 Comments
… would also need also to write not-modified pages if this will get sequential write. Say if we have …1 makes no difference. If you have a battery-backed disk controller cache, then the commit returns in less than … being broken. Most do not have RAID with BBU. With good RAID with BBU you can get 2000 …
Comment: Linux schedulers in tpcc like benchmark
January 31, 2009 By 19 Comments
…RAID 10 + BBU is probably the most common and natural choice for write stressed …write intensives, reads, and cpu bound moments, not just huge sustained writes) would give controller better chances to reorder properly before cache… (although MySQL offers INSERT DELAYED). Back to the subject, I don’…
Post: Living with backups
November 6, 2008 By 28 Comments
…RAID configurations, the performance gains are quite clear. Now going back to flushing the data out of the cache…tricks, but it’s mostly beyond your control. Otherwise, when copying physical data files, in…- mysql | ssh backup@storage-host /root/backup-tools/write_backup.sh This will read /mnt/…
Post: Why you don't want to shard.
August 6, 2009 By 34 Comments
… of writes being sent to the server. While the IO system can be improved with a RAID 10 controller w/battery backed write cache, the…?”. It’s a highly scalable architecture, and once you write scripts to be able to migrate users to/from shards… comes down to two reasons: The application developer has to write more code to be able to handle sharding logic (this…
Post: How to estimate time it takes Innodb to Recover ?
May 9, 2007 By 7 Comments
…variables are important. Checkpointing interval This is mainly controlled by size of log files as Innodb …of times per second. Database Size This comes back to the data locality but with same …this makes sure all OS/RAID caches are clean when recovery happens and also may help you to catch write cache…
