Re: Sharing disks amoung multiple software RAIDs

From: Kasper Sandberg
Date: Fri May 02 2008 - 17:44:21 EST


On Fri, 2008-05-02 at 09:25 +0100, David Greaves wrote:
> Kasper Sandberg wrote:
> > Im not treating it as a backup, what i want, is to make sure that if 1
> > disk dies, the data is still intact and ill hopefully be able to run
> > with 1 disk till the newly ordered one arrives
> Probably one of the main design objectives behind RAID/md

Exactly, but once people start saying: "Look how many problems people
post to the thread on
a weekly basis where people lose their data when md rebuilds go bad with
non-shared disks" i begin to worry..

>
> > So my question remains.. Is md raid1 not suited for this need? would it
> > be safer to run in non-raid1 mode and daily(maybe hourly) rsync
> > everything over to the second disk?
>
> md is 100% guaranteed perfect or your money back...
> rsync is 100% guaranteed perfect or your money back...
> your backups are 100% guaranteed perfect or your money back...
> your hard drives are 100% guaranteed perfect or your money back...
> your CPU and RAM are 100% guaranteed perfect or your money back...
> your CPU and PSU fans are 100% guaranteed perfect or your money back...
>
> Clearly if you want to panic over reliability you have lots of choices :)

I do not wish to panic, i merely wished to know if linux MD is believed
to work in most cases, or believed to do all sorts of weird stuff when
resyncing :)

>
> David
> PS, FWIW md has saved my data* countless times over the past 'n' years in
> exactly the scenario you describe.

It has also been useful to people i know, i just wished to be sure :)
and as Keld Jørn Simonsen and Helge Hafting's comments seems to confirm,
linux md IS nice and stable :)

and as said, what im looking for isnt an in-box backup solution, merely
safety in case one disk burns :)

>
> *(or more accurately has saved me from having to restore my data)

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