Am Dienstag, 8. Mai 2007 schrieb Ruslan Sivak: > Andreas Micklei wrote: > > Am Montag, 7. Mai 2007 schrieb Ruslan Sivak: > >> I've just installed the system as follows > >> > >> Raid1 for /boot with 2 spares (200mb) > >> raid0 for swap (1GB) > >> raid6 for / (10GB) > > > > NEVER EVER use raid0 for swap if you want reliability. If one drive fails > > the virtual memory gets corrupted and the machine will crash horribly > > (tm). Besides creating sepearte swap partitions on different physical > > discs will give you the same kind of performance, so using striping on a > > swap parition is kind useless for gaining performance. > > > > I suggest using raid-1 or raid-6 for swap, so the machine can stay up if > > one drive fails. > > Interesting thing... I build the following set up: > > /boot on raid1 > swap on raid0 > / on raid6 > /data on 2 lvm raid1's. Again: http://tldp.org/HOWTO/Software-RAID-HOWTO-2.html#ss2.3 > I shut down and plucked out one of the drives (3rd one I believe). > Booted back up, everything was fine. Even swap (I think). I, rebooted, > put in the old drive, hot added the partitions and everything rebuilt > beautifully. (again not sure about swap). Swap probably was not used at this time, or else your machine would have crashed. RAID-0 does not degrade when you plug out one disc, it simply fails. So the effect when swap is in use is the same as a RAM module going bad. > I decided to run one more test. I plucked out the first (boot) drive. > Upon reboot, I got greeted by GRUB all over the screen. Upon booting > into rescue mode, it couldn't find any partitions. I was able to mount > boot, and it let me recreate the raid1 partitions, but no luck with > raid6. This is the second time that this has happened. Am I doing' > something wrong? Seems when I pluck out the first drive, the drive > letters shift (since sda is missing, sdb becomes sda, sdc becomes sdb > and sdd becomes sdc). > > What's the proper repair method for a raid6 in this case? Or should I > just avoid raid6, and put / on 2 an LVM of 2 raid1's? Any way to set up > interleaving (although testing raid1 vs raid10 with hdparm -t gives > only marginal performance improvement). I haven't played with software RAID-6 and only use software RAID-5 on one machine currently (RAID-1 for boot). I am also not very familar with LVM, so I can't be of much help i fear. However, I find the Linux Software RAID HOWTO a very valuable resource, although it is a few years old: http://tldp.org/HOWTO/Software-RAID-HOWTO.html regards, Andreas Micklei -- Andreas Micklei IVISTAR Kommunikationssysteme AG Ehrenbergstr. 19 / 10245 Berlin, Germany http://www.ivistar.de Handelsregister: Berlin Charlottenburg HRB 75173 Umsatzsteuer-ID: DE207795030 Vorstand: Dr.-Ing. Dirk Elias Aufsichtsratsvorsitz: Dipl.-Betriebsw. Frank Bindel