RAID 0+1: possible with Suse 10.0?

Mr. Spencer · 04-22-2006, 12:41 PM

Greetings all.

I don't consider myself a newbie, since I've been using Suse since 8.2. More an amateur. That said, I do need a bit of help and no amount of searching has helped out.

First off, the setup:

ASUS K8N-E Deluxe with an AMD64 2800+ processor
1 40 GB ATA HD, used to install the OS on
2 160 GB Hitachi SATA drives
2 160 GB WD SATA drives

I've got Win XP Pro installed on the 40 GB drive a few days ago, since I'm planning on installing Suse, Slackware and FreeBSD and I've had problems in the past with getting GRUB and LiLo working correctly. So, I'm planning on using Acronis OS Selector, which has never let me down.

Now, the machine was a Suse-only machine till recently, with the WD drives, in RAID 0. After a perceived hd crash, I installed the Hitachis, in RAID 1. However, the crash wasn't due to hardware problems but due to the powerconnector to one of the drives coming loose.

Now, having had problems with ReiserFS in the past, I decided to go with Ext3 and try to build a RAID 0+1 setup, since I've got enough drives for it and finally try and use a few install dvd's I've got lying around. One thing I did notice was that both WD's show up as having only 149 GB while the Hitachis have 153.3 GB

Problem is, SUSE 10.0 only offers up RAID 0,1 or 5. I can setup the Hitachis as RAID 0, pointing to /home, as md0. I want to set up the WD to mirror the Hitachis. They'll show up as md1 but nowhere do I find any reference on how to set it up.

The Hitachis are attached to the Nvidia Nforce 3 connectors which allow RAID 0/1/0+1/JBOD. The WD are connected to 2 of the 4 Sil 3114 connectors (RAID 0/1/10/5/JBOD).

Is there a way to set it up? Do I need some extra software? Do I need to compile a kernel? Or do I need some piece of hardware to get it set up?

TIA for the help.

leandean · 04-22-2006, 11:30 PM

I would think you could set up the mirrors using Yast. Then Yast will only 'see' two drives, MD0 and MD1 so you could then stripe them. As for the size discrepency, WD has more built in overhead. When you create the mirrors, make sure that all four drives have the same block size.

You could also spend major money for a hardware pci raid card.

I haven't actually done this, but it sounds like an interesting scenerio

I'll have to give it a try.

jschiwal · 04-22-2006, 11:52 PM

Raid will work best if you only use the Master connection, so you may want to pick up another ide controller. Even on board ide raid is still software raid, so investing in a ide-raid controller may not effect performance as you might expect. Using just 2 160 GB drives, you should just use mirroring.

SuSE uses mdadm by default. You don't want to use raidtools if you already have a raid array set up. The /etc/init.d/boot.md first checks for mdadm.conf. If it finds it, the /etc/raidtab test is bypassed in an elseif.

Code:

        if test -f /etc/mdadm.conf -a -x /sbin/mdadm ; then
            echo "Initializing Multiple Devices..."
            /sbin/mdadm --assemble --scan
        elif test -f /etc/raidtab -a -x /sbin/raid0run ; then
            echo "Initializing Multiple Devices..."
            /sbin/raid0run -a
            if test -x /sbin/raidstart ; then
                /sbin/raidstart -a
            fi
        elif test -f /etc/mdtab -a -x /sbin/mdadd ; then
...

One other thing worth noting, is that a newer version of mdadm will work with raid10 types directly, instead of having to build it in two steps, but the YaST scripts may not do it this way. However if you create your /etc/mdadm.conf file manually, this may help. Don't bother upgrading from 9.3 to 10.0 on this account either, because SuSE 10.0 doesn't use the version I mentioned. I don't know what SuSE 10.1 will use.