Setting up RAID

[dmoulton]

The Ultra 2 that I am installing on has two 9 gig drives on it. I would like to RAID them together in simple linear mode. I have read through the generic RAID HOWTO, which is very useful. I have not yet installed Gentoo on the Ultra, so I would like to do this as part of an install. I would just like some more specific Gentoo related info on RAID.

I notice in the install HOWTO that you can declare partitions as RAID type partitions, so I assume that this is part of the process. I'm wondering if I can just partition both disks as RAID partitions, do the install, and then put them together ala the HOWTO after the installation.

If anybody can shed a little light on this, or point me to a doc that I have missed, I would appreciate it.

dm

[Weeve]

Section 6 of the x86 installation guide talks a little more about RAID

http://www.gentoo.org/doc/en/gentoo-x86-install.xml#doc_chap6

[dmoulton]

So I've made it a little further, but am stuck again. I may be going at this all wrong.

I have 2 9 gig drives in my Ultra 2. I fdisked both to type fd,ext3. I have a separate /boot partition. I did not set up RAID, but installed gentoo to sda. After the install, I set up /etc/raidtab and /etc/fstab as I think they should be. I then booted with the cd again and copied the raidtab into the ram disk, and did a mkraid /etc/raidtab. There were no errors and /proc/mdstat looked OK. When I reboot, I get "array md0 is already mounted!". /proc/mdstat seems to think everything is fine, but df -k says that /dev/md0 is a 8 gig partition, which is one drives worth.

Here are the various files:

mdstat:
Personalities : [linear] [raid0]
read_ahead 1024 sectors
md0 : active linear scsi/host0/bus0/target1/lun0/part2[1] scsi/host0/bus0/target0/lun0/part4[0]
17078592 blocks 32k rounding

unused devices: <none>

raidtab:
raiddev /dev/md0
raid-level linear
nr-raid-disks 2
chunk-size 32
persistent-superblock 1
device /dev/sda4
raid-disk 0
device /dev/sdb2
raid-disk 1

silo.conf
partition = 1
root = /dev/md0
timeout = 10
image = /boot/vmlinux
label = linux

kern.log
Jul 12 17:55:45 lorien kernel: md: linear personality registered as nr 1
Jul 12 17:55:45 lorien kernel: md: raid0 personality registered as nr 2
Jul 12 17:55:45 lorien kernel: md: md driver 0.90.0 MAX_MD_DEVS=256, MD_SB_DISKS=27
Jul 12 17:55:45 lorien kernel: md: Autodetecting RAID arrays.
Jul 12 17:55:45 lorien kernel: [events: 00000002]
Jul 12 17:55:45 lorien kernel: [events: 00000002]
Jul 12 17:55:45 lorien kernel: md: autorun ...
Jul 12 17:55:45 lorien kernel: md: considering scsi/host0/bus0/target1/lun0/part2 ...
Jul 12 17:55:45 lorien kernel: md: adding scsi/host0/bus0/target1/lun0/part2 ...
Jul 12 17:55:45 lorien kernel: md: adding scsi/host0/bus0/target0/lun0/part4 ...
Jul 12 17:55:45 lorien kernel: md: created md0
Jul 12 17:55:45 lorien kernel: md: bind<scsi/host0/bus0/target0/lun0/part4,1>
Jul 12 17:55:45 lorien kernel: md: bind<scsi/host0/bus0/target1/lun0/part2,2>
Jul 12 17:55:45 lorien kernel: md: running: <scsi/host0/bus0/target1/lun0/part2><scsi/host0/bus0/target0/lun0/part4>
Jul 12 17:55:45 lorien kernel: md: scsi/host0/bus0/target1/lun0/part2's event counter: 00000002
Jul 12 17:55:45 lorien kernel: md: scsi/host0/bus0/target0/lun0/part4's event counter: 00000002
Jul 12 17:55:45 lorien kernel: md0: max total readahead window set to 248k
Jul 12 17:55:45 lorien kernel: md0: 1 data-disks, max readahead per data-disk: 248k
Jul 12 17:55:45 lorien kernel: md: updating md0 RAID superblock on device
Jul 12 17:55:46 lorien kernel: md: scsi/host0/bus0/target1/lun0/part2 [events: 00000003]<6>(write) scsi/host0/bus0/target1/lun0/part2's sb offset: 8839168
Jul 12 17:55:46 lorien kernel: md: scsi/host0/bus0/target0/lun0/part4 [events: 00000003]<6>(write) scsi/host0/bus0/target0/lun0/part4's sb offset: 8239424
Jul 12 17:55:46 lorien kernel: md: ... autorun DONE.
Jul 12 17:55:46 lorien kernel: NET4: Linux TCP/IP 1.0 for NET4.0
Jul 12 17:55:46 lorien kernel: IP Protocols: ICMP, UDP, TCP
Jul 12 17:55:46 lorien kernel: IP: routing cache hash table of 4096 buckets, 64Kbytes
Jul 12 17:55:46 lorien kernel: TCP: Hash tables configured (established 32768 bind 32768)
Jul 12 17:55:46 lorien kernel: NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
Jul 12 17:55:46 lorien kernel: kjournald starting. Commit interval 5 seconds
Jul 12 17:55:46 lorien kernel: EXT3-fs: mounted filesystem with ordered data mode.
Jul 12 17:55:46 lorien kernel: VFS: Mounted root (ext3 filesystem) readonly.
Jul 12 17:55:46 lorien kernel: Mounted devfs on /dev
Jul 12 17:55:46 lorien kernel: Adding Swap: 499128k swap-space (priority -1)
Jul 12 17:55:46 lorien kernel: EXT3 FS 2.4-0.9.19, 19 August 2002 on md(9,0), internal journal
Jul 12 17:55:46 lorien kernel: md: array md0 already exists!


I have been looking through the howtos and other posts, both here and in the other forums. I haven't found something that quite describes this.

Do I need to perhaps RAID them together and then install gentoo?

Any help will be appreciated.

dm