-----Original Message-----
From: Kasper Sandberg [mailto:lkml@metanurb.dk]
Sent: Friday, May 02, 2008 4:44 PM
To: David Greaves
Cc: David Rees; David Lethe; alex14641@yahoo.com; Justin Piszcz; linux-raid@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: Re: Sharing disks amoung multiple software RAIDs
On Fri, 2008-05-02 at 09:25 +0100, David Greaves wrote:
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..
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 :)
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 :)
=======================
Since I am the person that wrote that "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 think need to clarify.
I was being too literal. md is a good solution (I use it myself). However, the OP wanted to "Make sure that if one disk dies, the data is still in tact".
Only way to do that is have a good offsite backup.
Nothing can prevent opportunity for data loss. I don't care what RAID level (with single redundancy) you use or whether you have software or hardware-based RAID .. rebuilds can not reconstruct data if you are in degraded mode and have an unrecoverable read error on surviving disks. It is not md's job or design point to insure data consistency check/repairs are run 24x7. As such, by definition, there is no way to insure that a md rebuild will always be successful.
David
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