… for MySQL. And yesterday one customer reported that just changing cfq to noop solved their InnoDB IO problems. I ran tpcc… disks in RAID10, controller Perc/6i with BBU) to compare cfq, deadline, noop and anticipatory (last one just to get number, I… (column bo in vmstat) during benchmark As you see noop / deadline can utilize disks much better. For reference I used tpcc…
Post: Living with backups
November 6, 2008 By 28 Comments
…: # cat /sys/block/sd?/queue/scheduler noop anticipatory [deadline] cfq noop anticipatory [deadline] cfq noop anticipatory [deadline] cfq In order to change you will just need… “cfq” > /sys/block/$device/queue/scheduler ; fi ; done # cat /sys/block/sd?/queue/scheduler noop anticipatory deadline [cfq] noop anticipatory deadline [cfq] noop anticipatory deadline [cfq] That…
Comment: Living with backups
November 18, 2008 By 28 Comments
… class) to slow down to ridiculously low speed! – Using the deadline scheduler (which was the default) gives the best performance in… read operation are fast and MySQL starts lagging slightly. – Using CFQ with default class, side read operation is about twice as… still a bit faster than using deadline, and MySQL is lagging behind significantly more than using deadline. The IO subsystem is a…
Post: Fast storage: 8 SSD Intel X-25M 80GB benchmarks
January 18, 2010 By 15 Comments
… rows) 3. For cards connected in hardware raids, DEADLINE performs much worse than CFQ. Sequential reads: – For sequential reads you can get…) – Cards connected in hardware raid is doing much better – DEADLINE outperforms CFQ here (which is different from random writes) – Software raid0 performed…
Comment: Linux IO Schedulers and MySQL
February 2, 2007 By 7 Comments
… also claims that the CFQ scheduler is the best overall for database applications. But it also looks like deadline may be an option as well. Am I correct in stating that the deadline scheduler offers better long-term performance compared to CFQ? Or am I misreading that graph…
Comment: Linux schedulers in tpcc like benchmark
October 27, 2009 By 19 Comments
… corrupt data when changing scheduler) EXT2+noop: 97MB/s XFS+cfq: 30MB/s Some comments on this setup: – XFS beats EXT… also being unstable – cfq vs noop makes a *lot* of difference. In this setup cfq seems close to broken. deadline is similar to…
Comment: Living with backups
July 1, 2009 By 28 Comments
… on IO-intensive tasks. IO classes (ionice) works only with CFQ, and as I point out in that post, even when using IO classes to give priority to MySQL, CFQ makes MySQL run slower than Deadline on my hardware. I haven’t tested…
Comment: Evaluating IO subsystem performance for MySQL Needs
March 5, 2008 By 23 Comments
… new hardware before and did not notice much difference between cfq and deadline schedulers. Here is an article from redhat’s website….com/magazine/008jun05/features/schedulers/ And it is probably why cfq is RHEL’s default scheduler now. We had a couple…
Comment: FlashCache: tpcc workload
May 26, 2010 By 18 Comments
… that allows many outstanding IO requests ( RAID10, SSD) CFQ just dies vs Deadline in OLTP workloads. See for example http://www.mysqlperformanceblog… when performance problem was healed just by one command echo deadline > /sys/block/sda/queue/scheduler
Comment: Linux schedulers in tpcc like benchmark
February 4, 2009 By 19 Comments
I used Deadline with MySQL for many years… Recently I wanted to test the CFQ Idle class for an IO-intensive job… RAID. Might be different for other subsystems, but for be deadline just rocks, even without BBU (6-drive Raid10 though)
