Bug#623611: Lot of IO errors during boot

[Ritesh Raj Sarraf]

On 06/23/2011 02:31 PM, Laurent Bigonville wrote:
> It's just to add a comment (tell me if it worth reopening the bug).
>

There's not much to do here. So let's leave it closed.

> I've discovered that the more LUN mapped to a machine you have, the
> more time the machine takes to boot (due to the IO errors) and well in
> some situations it's not acceptable.
> 

That's ought to happen given the design. Ideally, there should be a
mechanism to ignore the ghost devices. Have you discussed this on dm-devel?

BTW, how many devices (LUNs x Paths) are we talking here ?

> I've found on a centos ML[0] that loading the scsi_dh_rdac kernel
> module really early (in the initrd) could mitigate this issue. I've
> made some test and it seems to work if the module is loaded in init-top
> (and before udev). I'm not too sure this is possible to do, as it seems
> that the 1st script to load (scsi) modules is the udev one.
>

The only reason to put something into initrd is for early boot. In case
of storage, if your root LUN is on a SAN. Otherwise, I don't see a need.
But if you feel that putting it into initrd is helping, go with it. Does
the rdac module have any initialization delay ?


-- 
Ritesh Raj Sarraf | http://people.debian.org/~rrs
Debian - The Universal Operating System

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