PLEASE HELP!!! RAID problems with 10.04

[J]

On Mon, Apr 12, 2010 at 19:16, Alvin Thompson <alvin at thompsonlogic.com> wrote:
> On Apr 12, 2010, at 6:37 PM, Ioannis Vranos wrote:
>> Haven't you any backup?
>>
>>
>> I am not playing the "smart" here, but I suggest you make backups
>> regularly, and never install betas on production machines.
>
> I guess I should have, but I figured that since I had a RAID5 system, if a drive failed I was covered.  I didn't anticipate Ubuntu 10.04 butchering a RAID device/file system I specifically told it not to touch.

I really hate this for you, and I really wish I knew of a way to get
out of it...

But previously when this was brought up, this is what I meant when I
said I suspected you were using software RAID instead of "real" RAID.
By "real" RAID I meant hardware RAID, and not that onboard junk
either... I meant with an actual RAID HBA.  This is one of the big
reasons I have never trusted software RAID.

With hardware, in most cases, the array metadata is stored on the
disks themelves, and on the RAID adapter.  So if you have to swap out
adapters, most of the time, the new adapter can pick up the metadata,
rebuild and incorporate the old array automatically, and you're up and
running with no loss of data.  You can even build an array on one
system or enclosure, and then move those disks to a different
enclosure and rebuild the array that way.

With software RAID, in my own experience at least, there are far too
many ways to get screwed and lose everything.

This page is a bit dated (it's about 6 years old) but maybe it will help:
http://aplawrence.com/Linux/rebuildraid.html

Apple based, but may be of some use:
http://reviews.cnet.com/8301-13727_7-10330310-263.html

Something on building sw raid that may be interesting for pointers:
http://blogs.techrepublic.com.com/networking/?p=381

I really had considered using some sort of low-end RAID (and yes, I
even considered software RAID for about 5 minutes) as I have a lot of
important data (digital photography mostly) but instead, I went the
cheap way...  hard disks have an expected life time of so many
thousands of hours...  with SATA disks as cheap as they are, I just
bought an external connector that lets me plug any 3.5 or 2.5 inch
SATA drive into a USB Port, and I just rsync my important stuff to a
drive, pop that drive out and set it on a shelf until the next backup.
 I use two hard disks for this, so I've always got 3 copies of my data
on hard disk, and since those backup disks sit on a shelf with no
power, I won't have to worry about them going bad any time soon.

No, it's not RAID, but I can guarantee my data is safe this way, at
least to 99.999%.

RAID is no excuse for not having a back-up plan in place.

Good luck with this... I know what kind of pain losing important data is like.

Cheers
Jeff