[EMAIL PROTECTED] (Udi Finkelstein) wrote: > ----------------------------------------------------------------------- > My system 3 IBM disks, 22GB ATA 7200RPM, adn an intel server motherboard > (T440BX). > > Installed stock RH 6.0. 3 disks installed as /dev/hda, /dev/hdb, > /dev/hdc, > with ATAPI CDROM as /dev/hdd. > (1) The kernel reports that the BIOS says that /dev/hda is PIO, while > /dev/hdb > and d/ev/hdc use DMA. weired. BIOS settings, probably? > (2) The kernel reports that /dev/hda and /dev/hdb use 2748/255/63 > geometry, > while /dev/hdc is 43800/16/63. Even more weired. I've seen it several times, too, that the LBA is not recognized by the kernel for the second IDE channel, probably, buggy BIOS. > measured performance with hdparm -t /dev/hd[abc] and got a disappointing > 2.3MB/s. Forget about hdparm, it's a toy (I mean, hdparm -t). Use bonnie. > Solved with hdparm -d 1 /dev/hd[abc]. speed now goes to 16MB/s. > somehow this works even for large blocks. The command: > time dd if=/dev/hda of=/dev/null count=1024 bs=131072 > takes 7-8 seconds, yielding 16MB/s actual disk throughput !! never > expected > this! > The DMA setting above is kept somwehere on a file, as it retains the > value > even after reboot. ?? I hardly believe this. Maybe, in the BIOS? > Now comes the RAID part. I made a linear raid Why not RAID0? Generally, you'd get much better perfromance and could tune it to your specific needs. I've once done more or less extensive benchmarks; see http://plasma-gate.weizmann.ac.il/~fnevgeny/raid/raid0.gif. Also, comparison of performance of different (software) RAID levels: http://plasma-gate.weizmann.ac.il/~fnevgeny/raid/raid.gif. Regards, Evgeny -- ____________________________________________________________ / Evgeny Stambulchik <[EMAIL PROTECTED]> \ / Plasma Laboratory, Weizmann Institute of Science, Israel \ \ | Phone : (972)8-934-3610 == | == FAX : (972)8-934-3491 | | | URL : http://plasma-gate.weizmann.ac.il/~fnevgeny/ | | | Finger for PGP key >=====================================+ | |______________________________________________________________|
