On Fri, 5 Oct 2007 06:25:20 -0400 (EDT), Justin Piszcz wrote: > So you have 3 SATA 1 disks: Yeah, 3 of them in the array, there is a fourth standalone disk which contains the root fs from which the system boots.. > http://digital-domain.net/kernel/sw-raid5-issue/mdadm-D > > Do you compile your own kernel or use the distribution's kernel? Compile my own. > What does cat /proc/interrupts say? This is important to see if your > disk controller(s) are sharing IRQs with other devices. $ cat /proc/interrupts CPU0 CPU1 0: 132052 249369403 IO-APIC-edge timer 1: 202 52 IO-APIC-edge i8042 8: 0 1 IO-APIC-edge rtc 9: 0 0 IO-APIC-fasteoi acpi 14: 11483 172 IO-APIC-edge ide0 16: 18041195 4798850 IO-APIC-fasteoi sata_sil24 18: 86068930 27 IO-APIC-fasteoi eth0 19: 16127662 2138177 IO-APIC-fasteoi sata_sil, ohci_hcd:usb1, ohci_hcd:usb2 NMI: 0 0 LOC: 249368914 249368949 ERR: 0 sata_sil24 contains the raid array, sata_sil the root fs disk > > Also note with only 3 disks in a RAID-5 you will not get stellar > performance, but regardless, it should not be 'hanging' as you have > mentioned. Just out of sheer curiosity have you tried the AS > scheduler? CFQ is supposed to be better for multi-user performance > but I would be highly interested if you used the AS scheduler-- would > that change the 'hanging' problem you are noticing? I would give it > a shot, also try the deadline and noop. I did try them briefly. I'll have another go. > You probably want to keep the nr_requessts to 128, the > stripe_cache_size to 8mb. The stripe size of 256k is probably > optimal. OK. > Did you also re-mount the XFS partition with the default mount > options (or just take the sunit and swidth)? The /etc/fstab entry for the raid array is currently: /dev/md0 /home xfs noatime,logbufs=8 1 2 and mount says /dev/md0 on /home type xfs (rw,noatime,logbufs=8) and /proc/mounts /dev/md0 /home xfs rw,noatime,logbufs=8,sunit=512,swidth=1024 0 0 So I guess mount or the kernel is setting the sunit and swidth values. > Justin. Andrew - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
