Re: Software RAID in Woody --- General Issues
Lucas Barbuto said:
> Hi List,
> 1) Question: Is it important to have my boot partition (also my root
> partition, I don't have a seperate /boot) as part of an array? If I want
> this array for redundancy, I would have thought this was
> essential, but it looks like quite a difficult process. Is it worth the
> hassle of following the instructions in the HOWTO (which I find a bit
> confusing and haved managed to botch up once already)? Is there another
> option for a fully redundant system? If I just RAID my non-root
> partitions, is this still fairly safe?
depends on the setup. I usually do this where possible. I haven't
read the HOWTO but it's not the easiest thing to do. I've done it on
both SCSI and IDE systems. It involved(for me) installing to a different
disk(not part of the array), once the base system is running and you
have the raidtools and kernel setup the way you want, make a bootdisk,
power down, hook the drives your gonna use for raid up in their
final positions(even if it means moving the current disk to another
controller/channel), boot up with the floppy by specifying the root
filesystem on the original disk(not the soon-to-be-raid). configure
the raid array and create it(I personally use 2.2.19+ raid 0.90 patch).
switch to single user mode, copy the files over, update lilo and fstab,
reboot and it should come up..been a few months since I last did it.
> 2) Problem: I managed to get Software RAID working to an extent when
> I compiled all the RAID kernel components as modules (at least I was able
> to execute the 'mkraid' command to start constructing the array on the
> /home partition) but it's stopped working since I compiled
> support directly into the kernel. This could just be me doing something
> stupid, but I've checked my kernel configuration twice.
you don't mention what kernel your using or what tools your using.
I think there are 2 tools. raidtools and raidtools2. raidtools works only
on 2.2.x kernels, raidtools2 works only on 2.4.x kernels(some 2.3.x too)
or 2.2.x kernels with a special patch. raidtools2 (aka raid 0.90) supports
background rebuilding, as well as bootable raid1(not sure if raid 0.36
aka raidtools supports bootable raid1).
> Any other RAID advice anyone can offer (redundancy related) is also much
> appreciated, as I'm a bit of a RAID-newbie.
for simplist and most reliable operation use SCSI disks on a supported
SCSI raid controller(e.g. Mylex Acceleraid). And if nor not sure I
would probably run some tests so you know how to recover from a failure.
With raid 0.36 it was easy enough, the partitions were exact mirrors
of each other, i just had to boot from CD, re-load lilo onto the other
disk and keep goin. I haven't tested recovery from raid 0.90 but the
process is probably similar. What is most important to me is not
maintaining uptime during an outage but having a disk with a good copy
of the data if the other goes down.
I was lucky enough to find a kickass deal on Mylex Acceleraid 150s at
a site called compgeeks.com, the cards retail for around $250 I picked
up 2 for $40/ea. they look brand new or refurb maybe, 4MB cache,
single channel ultra 2 scsi, have had one of them driving 5x9.1GB disks
in my redhat box for the past 2 months or so without any trouble(except
grub doesn't like it). I've been lookin on their site to see if that
product comes back in stock..sofar haven't seen a trace. glad I got
em when I did!!
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