Does anyone know any of any disadvantages with raid 10? We have 4 identical SATA 320 GB Hard disks and we were thinking of using Linux software RAID 10. We actually did it on a trial system and it seemed to work fine. We just created 2 raid 1 devices initially and installed edubuntu 7.04 on one of them using LVM and automatic partitioning.
Once we had installed we used mdadm to raid0 the two raid 1 devices together. When we tried to use Sysrescue CD to copy an image of the root (/) partition we ran into some problems. Someone suggested the errors might be caused by the RAID 10 and advised use to just use RAID 1 (leaving the two extra drives as spares.) I am not convinced though. It seems like a waste to have 2 extra drives and not use them to boost performance. Any thoughts or tips? Krsnendu dasa On 26/08/2007, Stefano Rivera <[EMAIL PROTECTED]> wrote: > Hi Joe (2007.08.25_21:35:38_+0200) > > My wish list: > > Step by step instructions, with a FAQ, some screen snapshots etc. > > Things like, now you have completed this so you should see this... > > Every distro is different. These things aren't static. But when you are > used to it, you know what to do. > > Software Raid 10 in linux is rather new, and so probably isn't well > documented. Personally, I've never used RAID 10, all my servers use RAID > 1, and if they have lots of disks, RAID 5. (Often system on RAID1, data > on RAID5) And they use LVM on top of that. > > The debian installer (which is on the ubuntu alternate install CDs) does > software RAID and LVM, and it's easy. The principle to create a RAID > device is: > * Create a partition on each drive, and set it's type to RAID. > * Go into the RAID menu, and create a RAID device out of those > partitions. > * Now on the partitioning screen, you'll see a RAID drive /dev/md* turn > it into an LVM PV or a filesystem. > > My normal approach is: > 2 system disks, not massive, but good value for money size, with 2 > partitions on them > * The first partition is for /dev/md0: maybe 10GB. It houses / > * The second partition is for /dev/md1: It houses an LVM PV & VG called > system. > * /home is an LV on system > * swap is an LV on system > * /usr is an LV on system, if my install grows beyond 10G > * Anything else special is an LV on system (i.e. /srv/www or /tmp or > /var/spool/squid) > If it's a big server, The rest of the disks contain a single partition > for RAID5, which is a separate LVM group, data. > > > How do I set it up so it boots? > > The best approach is to make sure that /boot is readable without > anything special. So make sure it's part of a RAID1. > > If you are using kernels without initrds (which all my debian servers > do), then you want the whole / to be like that. This also helps with > recovery. > > > Which drives should be paired together? > > I don't follow, aren't the drives all identical? > > > (Is each SATA drive on its own channel? > > Yes. SATA doesn't share channels, unless you use port multipliers (which > aren't currently supported in Linux, AFAIK, and anyway, the SATA bus has > enough bandwidth to handle a few drives on each port). > > > Do I have to do anything special for swap? > > If you want performance, you can create a single swap partition on each > drive, and just swapon them all. This has no redundancy, i.e. disk goes > down the server will crash. > > More common is to just stick the swap on RAID/LVM like everything else. > > SR > > -- > Stefano Rivera > http://rivera.za.net/ > H: +27 21 794 7937 C: +27 72 419 8559 > > -- > edubuntu-users mailing list > [email protected] > Modify settings or unsubscribe at: > https://lists.ubuntu.com/mailman/listinfo/edubuntu-users > -- edubuntu-users mailing list [email protected] Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/edubuntu-users
