We hired a consultant to help us increase the capacity of our MySQL cluster, and the first thing (almost only thing) he did was to measure the disk i/o speed of our servers.
I am interested in a comparison of disk i/o on similar systems to what we have:
- Our MySQL servers are virtual servers running on 32 bit VMWare ESX 3.5 with a SCSI SAN (Raid 5), and the Virtual servers themselves are running Debian Etch, and MySQL version 5.0.32
Running the following commands on the MySQL box give these results for me (which the consultant described as "Terribly slow":
time dd if=/dev/zero of=OUT.tmp bs=1M count=1000 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 71.3347 seconds, 14.7 MB/s real 1m13.596s user 0m0.052s sys 0m56.932s time dd if=OUT.tmp of=/dev/null bs=1M count=1000 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 21.8202 seconds, 48.1 MB/s real 0m21.902s user 0m0.012s sys 0m7.948s
Are these results indeed "Terribly slow"?
I would be interested in comparing the results other people get from these 2 commands on their dedicated MySQL boxes - particularly if it is a 32-bit virtual machine.