SAN vs Local-disk :: innodb_flush_method performance benchmarks

2012/01/06 by admin in MySQL Enteprise, MySQL Server | 10 Comments

If you’ve been tuning your MySQL database and have wondered what effect the innodb_flush_method settings have on write performance, then this information might help. I’ve recently been doing a lot of baseline load tests to show performance differences between localdisk and the new SAN we’re deploying. Since we run InnoDB for everything in production, and writes are very heavy, I decided to run comparison tests between two identical servers to find the best setting for innodb_flush_method. We have the following specs for the hardware:

  • Dell R610
  • 24 core Intel Xeon X5670 @ 2.93ghz
  • 72GB ECC RAM
  • Brocade 825 HBA
  • Local disk: RAID-10 15K SAS Ext3 (ugh)
  • SAN: Oracle 7420 with four Intel Xeon X7550 @ 2.00GHz, 512GB RAM, 2TB read-cache(MLC-SSD), 36GB write cache (SLC-SSD), 3 disk shelves populated with 60x2TB 7200RM SATA drives setup in mirrored format with striped logs, dual 8Gb FC links to redundant fabric, connected to Brocade DCX 8510-4.
  • The my.cnf file being used for the tests: click-click

I’m using the following sysbench command to run the tests. On each server the same commands are used. I ran a 1B row prepare prior to the 1B row test.

sysbench –db-driver=mysql –num-threads=64 –max-requests=1000000000 –max-time=3600 –test=oltp –verbosity=3 –validate=off –oltp-test-mode=complex –oltp-read-only=off –oltp-table-name=sbtest –oltp-table-size=1000000000 –oltp-dist-type=special –mysql-host=localhost –mysql-port=3306  –mysql-table-engine=innodb run

On the server that is utilizing SAN paths there are two LUNS presented for MySQL use. /db/data01 for InnoDB data files, /db/logs01 for InnoDB logs. These filesystems are both formatted as XFS. The server running local-disk tests is running Ext3. I might run some more tests later with the local-disk setup as XFS if time allows.

Here are the results. Clearly a well designed SAN infrastructure is superior to even RAID-10 15K SAS drives. And of course you can see the different performance values from using O_DIRECT for the innodb_flush_method for the different data storage mediums.

1B Row Complex Transactional Test, 64 threads

  • SAN O_DIRECT: read/write requests: 31560140 (8766.61 per sec.)
  • SAN O_DSYNC: read/write requests: 5179457 (1438.52 per sec.)
  • SAN fdatasync: read/write requests: 9445774 (2623.66 per sec.)
  • Local-disk O_DIRECT: read/write requests: 3258595 (905.06 per sec.)
  • Local-disk O_DSYNC: read/write requests: 3494632 (970.65 per sec.)
  • Local-disk fdatasync: read/write requests: 4223757 (1173.04 per sec.)
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Frustration with Community vs Enteprise

2008/12/15 by admin in MySQL Enteprise | 12 Comments

I was working on a client’s server today to troubleshoot some variances between the result timing of some queries. Guess what I came across – the profiler is not available in certain enterprise releases but it is available on community versions of the same release number.

I can understand if that feature was something that wasn’t fully tested in the enterprise code base and thus was only released in the community version – but if that’s the case then I don’t understand why the same version releases of Community and Enterprise can have different feature sets. That goes against the whole idea of versioning. Someone correct me if I’m wrong here but that is very frustrating.

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