I have an unusual problem with Disk transfer speeds on a virtual Linux environment.
This environment consists of an ESX host running 3i, 3.5.0, 153875 and 2 Debian 5.0 Linux virtual machines.
When booting the machines have a hdparm transfer rate output of:
Timing cached reads: 1418 MB in 2.00 seconds = 707.95 MB/sec
Timing buffered disk reads: 132 MB in 3.01 seconds = 43.93 MB/sec
After a couple of days, the machines become sluggish and the same test produces:
Timing cached reads: 162 MB in 2.00 seconds = 80.99 MB/sec
Timing buffered disk reads: 12 MB in 3.78 seconds = 3.18 MB/sec
The command that is being run is hdparm -tT /dev/sda
Any ideas on why this is occurring, I cant see anything obvious in the logs that will cause this.