> From: steve rader
> Am I following this correctly: in this senario, are /boot and
> /boot1 non-raid "stub root" filesystems with kernel(s) for
> launching the "real" root-raid1 system with one or the other of
> the root-raid1 disks offline? That would be pretty sweet eh.
> If so, what does lilo.conf look like?
Doh. Never mind. Luca Perugini <[EMAIL PROTECTED]>
sent me what appears to be a cogent recipe for this
(ca. Jan 6th 1999.) (Luca: thanks!) I'll report back soon.
later
steve
- - -
systems guy
wiscnet.net
- - -
Date: Fri, 05 Feb 1999 00:35:46 +0100
To: steve rader <[EMAIL PROTECTED]>
From: Luca Perugini <[EMAIL PROTECTED]>
Subject: Re: RAID1 on / for RH 5.2
Have look at this.
>Date: Wed, 06 Jan 1999 10:11:45 +0100
>To: "Jack Gavigan" <[EMAIL PROTECTED]>
>From: Martin Bene <[EMAIL PROTECTED]>
>Subject: Re: RAID1 on / for RH 5.2
>Cc: <[EMAIL PROTECTED]>
>
>Hi Jack,
>
>At 17:59 04.01.99 -0000, you wrote:
>>I can sympathise. I decided to postpone trying to RAID the root partition
>>until later - much later. At least until I fully understand Linux Software
>>RAID. The Software RAID Howto is less of a HOWTO than a FAQ for experienced
>>RAIDers... Took me about 20 minutes to figure out that mdadd and raidadd are
>>actually the same thing. :)
>
>Been there, done that :-)
>
>1) The docs are way out of sync with reality, there was a mayor overhaul of
>the raid code which is available on ftp://ftp.kernel.org/pub/daemons/raid
>(or on one of the mirrors). Look for raidtools 0.90 at
>alpha/raidtools-19981214-0.90.tar.gz and the coresponding kernel stuff at
>alpha/raid-0145*
>
>2) The new code has much better support for root on raid devices -
>activation & shutdown of raid devices is included in the kernel. You will
>still need a small non-raid partion or disk for storing the kernel and
>other stuff needed by lilo at boottime. Also the new raidtools use a config
>file /etc/raidtab which really helps in making things easier to manage.
>
>Here's a short account on how I got my raid stuff configured. Partitioning
>of disks was done previously, here's what my partition table(s) look like:
>
> Device Boot Begin Start End Blocks Id System
>/dev/sda1 1 1 1 8001 83 Linux native
>/dev/sda2 * 2 2 197 1574370 fd Unknown
>/dev/sda3 198 198 1095 7213185 fd Unknown
>/dev/sda4 1024 1096 1111 128520 82 Linux swap
>
> Device Boot Begin Start End Blocks Id System
>/dev/sdb1 1 1 1 8001 83 Linux native
>/dev/sdb2 * 2 2 197 1574370 fd Unknown
>/dev/sdb3 198 198 1095 7213185 fd Unknown
>/dev/sdb4 1024 1096 1111 128520 82 Linux swap
>
>/dec/sda1 and /dev/sdab1 are mounted on /boot0 and /boot11 and hold just
>the stuff needed by lilo to load the kernel.
>
>For me installation was fairly easy since I've already got serveral systems
>running linux; I just built raid tools & a raid kernel on one of the old
>systems and copied tools+kernel onto the setup disk; this way you can set
>up your raid devices while running off a floppy and install right onto the
>/dev/md* device.
>
>* apply the raid0145-19981215-2.0.36 patch to a kernel 2.0.36 to include
>the new raid stuff.
>* Configure the kernel, say yes to "autodetect RAID partition" and to the
>RAID modes you want to use. build & install the kernel.
>* compile and install the raid tools v0.90 (./configure; make; make install)
>* prepare a configuration file for the raid devices, this goes in
>/etc/raidtab by default. Here's what mine looks like:
>-----------------------------------------------------------------------------
># /etc/raidtab raid config file
>#
>raiddev /dev/md0
>raid-level 1
>nr-raid-disks 2
>nr-spare-disks 0
>chunk-size 64
>
>device /dev/sda2
>raid-disk 0
>
>device /dev/sdb2
>raid-disk 1
>
>#
>raiddev /dev/md1
>raid-level 1
>nr-raid-disks 2
>nr-spare-disks 0
>chunk-size 64
>
>device /dev/sda3
>raid-disk 0
>
>device /dev/sdb3
>raid-disk 1
>-----------------------------------------------------------------------------
>
>This configures two raid-1 mirrors, with two disks each.
>
>* Now, initialize your raid devices:
> mkraid /dev/md0
> mkraid /dev/md1
>
>Your raid devices are online and useable now, hovever it'll take a while
>for initialisatzion of mirrors to finish (in background). you can check the
>status of your raid devices by doing cat /proc/mdstat
>
>* put a filesystem on your devices
> mke2fs /dev/md0
> mke2fs /dev/md1
>
>* enable automatic initialisatzion of raid devices by kernel. Use fdisk to
>change the type of the partitions which are part of raid devices to FD:
> fdisk /dev/sda
> Command (m for help): t
> Partition number (1-4): 2
> Hex code (type L to list codes): fd
>
>You'll neither have to use raidstart on startup, nor raidstop on shutdown
>with this configuration, both are performed automagically by the kernel.
>
>If you don't want to have your devices automatically initialized, you can
>of course leave the partition type alone and use raidstart /raidstop to
>initialize & shutdown the devices from system startup scripts.
>
>That's it for setup of kernel & partitions.
>
>What took me quite some time was finding a reasonable configuration for
>lilo; the aim is to have BOTH sda and sdb bootable so the system still
>starts in case one of the disks fails, and to be able to select a kernel
>image from either disk on bootup in case just a kernel image somehow gets
>damaged. I ended up with two lilo config files, one for each disk, stored
>as /etc/lilo.conf.sda and /etc/lilo.conf.sdb.
>
>-----------------------------------------------------------------------------
># LILO configuration file /etc/lilo.conf.sda
>#
># Start LILO global section
>boot = /dev/sda
>disk = /dev/sda
>map = /boot0/boot/map
>install = /boot0/boot/boot.b
>backup = /boot0/boot/boot.0800
>message = /boot0/boot/boot_message.txt
>prompt
>timeout = 50
>vga = normal
>password = xxxxxxxxxx
>restricted
># End LILO global section
># Linux bootable partition config begins
># Images in Disk 0
>image = /boot0/vmlinuz
> root = /dev/md0
> label = Linux_Disk0
> read-only
>image = /boot0/vmlinuz.001
> root = /dev/md0
> label = Linux_Disk0_old
> read-only
># Images in Disk 1
>image = /boot1/vmlinuz
> root = /dev/md0
> label = Linux_Disk1
> read-only
>image = /boot1/vmlinuz.001
> root = /dev/md0
> label = Linux_Disk1_old
> read-only
># Linux bootable partition config ends
>-----------------------------------------------------------------------------
>
>In the file for the 2nd disk, notice the disk = /dev/sdb bios=0x80 line.
>this thells lilo that on bootup, this is acutually going to be the first
>disk, even though it's currently the second disk.
>
>-----------------------------------------------------------------------------
># LILO configuration file /etc/lilo.conf.sdb
>#
># Start LILO global section
>boot = /dev/sdb
>disk = /dev/sdb bios=0x80
>map = /boot1/boot/map
>install = /boot1/boot/boot.b
>backup = /boot1/boot/boot.0800
>message = /boot1/boot/boot_message.txt
>prompt
>timeout = 50
>vga = normal
>password = xxxxxxxxxx
>restricted
># End LILO global section
># Linux bootable partition config begins
># Images in Disk 1
>image = /kernel1/vmlinuz
> root = /dev/md0
> label = Linux_Disk1
> read-only
>image = /kernel1/vmlinuz.001
> root = /dev/md0
> label = Linux_Disk1_old
> read-only
># Images in Disk 0
>image = /kernel0/vmlinuz
> root = /dev/md0
> label = Linux_Disk0
> read-only
>image = /kernel0/vmlinuz.001
> root = /dev/md0
> label = Linux_Disk0_old
> read-only
># Linux bootable partition config ends
>-----------------------------------------------------------------------------
>
>Now some hints on maintenance of your raid devices: The raid devices are
>automatically checked by the kernel; in case of problems (power down
>without proper shutdown for example) the devices are automatically
>resynchronized, again see /proc/mdstat for current status.
>
>If one of your disks actually fails and has to be replaced you can use the
>raidhotremove and raidhotadd programs (actually just symlinks to
>/sbin/raidstart, automatically created on installation of raidtools) to
>remove defect drives and/or to add new devices. say your disk /dev/sdb
>died and had to be replaced; your system is now running solely off
>/dev/sda, /proc/mdstat shows that only the first disk in the mirror(s) is
>active.
>
> raidhotremove /dev/md0 /dev/sdb2
> raidhotremove /dev/md1 /dev/sdb3
>
>Now you've got mirrors consisting of just one disk each, but at least
>they're healty again.
>
> raidhotadd /dev/md0 /dev/sdb2
> raidhotadd /dev/md1 /dev/sdb3
>
>Will add the new disk to the mirror(s) and initialize the new disk so you
>end up with a consistant mirror again. Syschronisation runs in the
>background, again see /proc/mdstat for current status.
>
>Hope this helps,
>
>Martin
>--------------------------------------------------
> Martin Bene vox: +43-664-3251047
> simon media fax: +43-316-813824-6
> Andreas-Hofer-Platz 9 e-mail: [EMAIL PROTECTED]
> 8010 Graz, Austria
>--------------------------------------------------
>finger [EMAIL PROTECTED] for PGP public key
>
>
-*************************
Luca Perugini
Laureando in Ing.Informatica
LinuxManship
WebMaster http://www.uisp.it
System Manager at uisp.it
mailto:[EMAIL PROTECTED]
mailto:[EMAIL PROTECTED]
-**************************
