Installing on hardware raid - Promise TX2000 (PDC20271)

robbz · n00b Joined: 27 Mar 2005 Posts: 33

I want to install Gentoo on a machine with hardware raid, which is the promise Tx200(PDC20271). I see that the kernel 2.6 has support for it, but I've been looking through the online documentation and can't find any guide on installing on a hardware raid. The disks are already set up and the raid array created.

If anyone has a link to a guide or somehting would appreciate some help.
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RD

Rad · Posted: Wed May 25, 2005 3:02 pm Post subject:

I think I wouldn't do HARDWARE Raid with that card. The thing is, on Linux, the native software Raid often performs better and certainely is more flexible and more recoverable in case of failure (yeh- well not that raid is recoverable in many cases...).
EDIT: I forgot to point out that the promise driver probably does only software raid anyways.

And about your actual question: Well if you need a driver that's not in the kernel to be loaded before your system can boot (usually only harddisk related ones), you do the initrd or maybe the newer initramfs trick.
I hope that link here still is correct, as I haven't used an initrd to "pre-load" a driver for a looong time now. Note that you also need initial ram disk support compiled into the kernel, it should be under the file systems category.

robbz · n00b Joined: 27 Mar 2005 Posts: 33

I thought that the hardware raid would be better and easier to administer because say a drive fail, you just add the new one and it will rebuild the array. I'm a bit confused, does this mean that I should remove the card and use software raid instead.
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RD

markkuk · Guru Joined: 29 Nov 2002 Posts: 446

robbz · n00b Joined: 27 Mar 2005 Posts: 33

So is there anyone who installed a system on one of these cards. I can't seem to find any guide or anything close to give me an exact idea. I was looking at this link http://www.gentoo.org/doc/en/gentoo-x86-tipsntricks.xml and saw some posts on the forum, but nothing really helpful as yet. I guess I have to wait untilt he weekend and do some research. I'm just trying to find some good information to start with, because I don't want to spend a long time experimenting.
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RD

robbz · n00b Joined: 27 Mar 2005 Posts: 33

I also found this http://gentoo-wiki.com/HOWTO_Gentoo_Install_on_Software_RAID_mirror_and_LVM2_on_top_of_RAID one the Gentoo Wiki. I'm understanding it more now. One thing I don't understand yet though, is if say a hard drive fails and I replace it. Do I just let the promise utility in the BIOS rebuild the new hard drive and add it back tot he array? Do I have to do anything manually.
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RD

robbz · n00b Joined: 27 Mar 2005 Posts: 33

I booted from the live cd and followed the instructions fromt eh Gentoo site and also fromt he wiki and did modprobe raid1 first. But, the only device I can lood is /dev/hdg, I have to 40GB Maxtor drives, I'm using a Promise TX2000 and using an Asus motherboard. In the BIOS settings the boot device is set as SCSO Boot Device. My question is, does the one hard drive that is being seen is it the raid array I'm seeing, and can I just go ahead and install on this? I'm confuse because from what I read ont he forums and fromt he Gentoo wiki, the promise TX200 uses software raid I can I have to set it up that way. The raid array is already set up using Raid1, currently I'm running FreeBSD on it.
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RD

robbz · n00b Joined: 27 Mar 2005 Posts: 33

Ok, my BooBoo. I rebooted again and did dmesg to see the disks. and saw /dev/hde and /dev/hdg and I'm able to see both of them with fdisk. Guess it was the PEBKAK (Problem Exists Between Keyboard And Chair). I'm back to installing now.
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RD

NeddySeagoon · Posted: Thu Jun 09, 2005 6:34 pm Post subject:

robbz,

You can use Linux dmraid or kernel raid.

dmraid is compatible with windows , if thats a concern, as it uses the BIOS to put the drives into a raid array which you then partition in the normal way. You need a soecial liveCD for that, See some of my recent posts.

Kernel raid is not windows compatible (or dmraid compatible). you partition your drives first, then put the partitions into raid array(s).
This allows several raid levels on the same set of drives.
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Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

robbz · n00b Joined: 27 Mar 2005 Posts: 33

I'm having trouble creating the array when I issue :

mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/hde1 /dev/hdg1

It tells gives an error /dev/hde1:

mdadm: size set to 31616k
md: could not bd_claim hde1.
md: error, md_import_device() returned -16
mdadm: ADD_NEW_DISK for /dev/hde1 failed: Device or resource busy
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RD

robbz · n00b Joined: 27 Mar 2005 Posts: 33

I should also mention that I'm using 2 40GB Maxtor drives each one are on one controller for the raid card, and the CD-Drive is connected to my mainboard.
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RD

robbz · n00b Joined: 27 Mar 2005 Posts: 33

It might have been a seeting in the BIOS or something, anyhow I just installed back FreeBSD ont hat machine. I followed the same procedure on another machine I'm going to install MythTV on and I got the software raid (RAID1) setup with no problems at all using the same
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RD