Inspired by NILFS: A File System to Make SSDs Scream and some customers asked if they should try NILFS on their SSD disks I decided to run quick tests to see how it performs. Installation on our Ubuntu 8.10 with SSD disk (Intel X25-E, 32GB) was pretty plain and I got partition with NILFS without [...]
Dissection of EC2 / EBS volume
August 7, 2009 By 4 Comments
So during preparation of XtraDB template for EC2 I wanted to understand what IO characteristics we can expect from EBS volume ( I am speaking about single volume, not RAID as in my previous post). Yasufumi did some benchmarks and pointed me on interesting behavior, there seems several level of caching on EBS volume.
EC2/EBS single and RAID volumes IO benchmark
August 6, 2009 By 14 Comments
During preparation of Percona-XtraDB template to run in RightScale environment, I noticed that IO performance on EBS volume in EC2 cloud is not quite perfect. So I have spent some time benchmarking volumes. Interesting part with EBS volumes is that you see it as device in your OS, so you can easily make software RAID [...]
Disaster: LVM Performance in Snapshot Mode
February 5, 2009 By 55 Comments
In many cases I speculate how things should work based on what they do and in number of cases this lead me forming too good impression about technology and when running in completely unanticipated bug or performance bottleneck. This is exactly the case with LVM Number of customers have reported the LVM gives very high [...]
Pretending to fix broken group commit
February 2, 2009 By 11 Comments
The problem with broken group commit was discusses many times, bug report was reported 3.5Â years ago and still not fixed in MySQLÂ 5.0/5.1 (and most likely will not be in MySQLÂ 5.1). Although the rough truth is this bug is very hard (if possible) to fix properly. In short words if you enable replication (log-bin) on server [...]
Beware: ext3 and sync-binlog do not play well together
January 21, 2009 By 19 Comments
One of our customers reported strange problem with MySQL having extremely poor performance when sync-binlog=1 is enabled, even though the system with RAID and BBU were expected to have much better performance. The problem could be repeated with SysBench as follows:
1 | ./sysbench --num-threads=2 --test=oltp --oltp-test-mode=complex --oltp-table-size=100000 --oltp-distinct-ranges=0 --oltp-order-ranges=0 --oltp-sum-ranges=0 --oltp-simple-ranges=0 --oltp-point-selects=0 --oltp-range-size=0 --mysql-table-engine=innodb --mysql-user=root --max-requests=0 --max-time=60 --mysql-db=test run |
Evaluating IO subsystem performance for MySQL Needs
March 5, 2008 By 23 Comments
I’m often asked how one can evaluate IO subsystem (Hard drive RAID or SAN) performance for MySQL needs so I’ve decided to write some simple steps you can take to get a good feeling about it, it is not perfect but usually can tell you quite a lot of what you should expect from the [...]
Sysbench evaluation of iSCSI performance
July 6, 2006 By 2 Comments
Partha Dutta posted pretty interesting post about iSCSI vs SCSI performance using SysBench. This is nice to finally see some iSCSI benchmarks done with MySQL – something we were planning to do for a while but never ended up doing, mainly due to lack of hardware available for tests. It is also good to see [...]
Group commit and XA
May 19, 2006 By 8 Comments
Returning to post Group commit and real fsync I made several experiments: I ran sysbench update_key benchmarks without —log-bin, with —log-bin, and with —log-bin and —innodb-support-xa=0 (default value is 1). Results (in transactions / sec) threads without —log-bin —log-bin —log-bin and —innodb_support-xa=0 1 1218.68 614.94 1010.44 4 2686.36 667.77 1162.60 16 3993.59 666.14 1161.56 64 [...]
Group commit and real fsync
May 3, 2006 By 9 Comments
During the recent months I’ve seen few cases of customers upgrading to MySQL 5.0 and having serious performance slow downs, up to 10 times in certain cases. What was the most surprising for them is the problem was hardware and even OS specific – it could show up with one OS version but not in [...]
