On Sat, 22 May 2004 09:13 am, David Kempe wrote: > Hey anyone have a simple explanation for this phenomenom? > I have 2 * 120Gb SATA drives on an Intel ICH5 controller. > My hdparm scores for both drives are : > > scythe:~# hdparm -t /dev/hdc > > /dev/hdc: > Timing buffered disk reads: 168 MB in 3.02 seconds = 55.55 MB/sec > > scythe:~# hdparm -t /dev/hdd > > /dev/hda: > Timing buffered disk reads: 168 MB in 3.00 seconds = 55.93 MB/sec
My guess is that it's measuring the speed from the buffers and not from the physical drive....just a thought. The other thing is that resynching a mirror is a 2-way thing, and because the data is all "different" (blocks) the buffers will quickly become exhausted and the drive will be doing raw transfers to and from the disk. The hdparm scores are only reading data moving in one direction. Still, I'd expect you to be seeing about 1/2-1/3 the speed of the hdparm scores. I'm assuming DMA is enabled and the controller is assigned an IRQ correctly (not sharing one with something like a NIC etc). Other than that, I'm out of ideas. James -- ... I want a COLOR T.V. and a VIBRATING BED!!! -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
