Re: weird issues with raid1

On Wed, Dec 17, 2008 at 10:50 PM, Jon Nelson
[off-list ref] wrote:

On Wed, Dec 17, 2008 at 10:42 PM, Neil Brown [off-list ref] wrote:

quoted

On Tuesday December 16, neilb@suse.de wrote:

quoted

On Monday December 15, jnelson-linux-raid@jamponi.net wrote:

quoted

On Mon, Dec 15, 2008 at 3:33 PM, Neil Brown [off-list ref] wrote:

quoted

On Monday December 15, jnelson-linux-raid@jamponi.net wrote:

quoted

Aha!  This explains a question I raised in another email. What
happened there is a previously fully active member of the raid got
added, somehow, as a spare, via --incremental. That's when the entire
raid thought it needed to be rebuilt. How did that (the device being
treated as a spare instead of as a previously fully active member)
happen?

It is hard to guess without details, and they might be hard to collect
after the fact.
Maybe if you have the kernel logs of when the server rebooted and the
recovery started, that might contain some hints.

I hope this helps.

Yes it does, though I generally prefer to get more complete logs.  If
I get the surrounding log lines then I know what isn't there as well
as what is - and it isn't always clear at first which bits will be
important.

The problem here is that --incremental doesn't provide the --re-add
functionality that you are depending on.  That was an oversight on my
part.  I'll see if I can get it fixed.
In the mean time, you'll need to use --re-add (or --add, it does the
same thing in your situation) to add nbd0 to the array.

Actually, I'm wrong.
--incremental does do the right thing w.r.t. --re-add.
I couldn't reproduce your symptoms.

OK.

quoted

It could be that you are hitting the bug fixed by
 commit a0da84f35b25875870270d16b6eccda4884d61a7

That sure sounds like it. I'd have to log to see what happened,
exactly, but I've added substantial logging around the device
discovery and addition section which manages this particular raid.

quoted

You would need 2.6.26 or later to have that fixed.
Can you try with a newer kernel???

I hope to be giving opensuse 11.1 a try soon, which uses 2.6.27.X
afaik.  I suspect I can also backport that patch to 2.6.25 easily.

The kernel source for 2.6.25.18-0.2 (from suse) has this patch
already, so I was already using it.

Perhaps this weekend or some night this week I'll find time to try to
break things again.

-- 
Jon