Re: [dm-devel] [multipath] SCSI device capacity mess

[Lars Marowsky-Bree <lmb@suse.de>]

On 2004-10-27T21:02:39, christophe varoqui <christophe.varoqui@free.fr> wrote:

> > As a note, this is one mode the EMC CLARiiON arrays can also operate in.
> > Even worse, they won't present the block device at all, just the SCSI
> > generic mode. However, for the CLARiiONs, they can be configured to
> > behave sanely and reply to a READ_CAPACITY too (just all I/O will be
> > errored), if setting the failovermode to 1.
> > 
> > I wonder whether your system can also be configured as such?
> Yes it could, but it's a controler wide setting.

Not per LUN? Too bad.

> Compatibility with other OS sharing the same controlers might impose
> this mode though. So I'd like to straight this situation up.

Then I think hardware-specific hooks in the dm-mpath are the way to go.
We already have them in place for the priority group initialization code
anyway, we can add them for anything else which needs them, like this
one.

> I wonder if it's not simpler just to remove the NOSTARTONADD flag on
> this devices in scsi_devinfo.c. I tested that and all the READ CAPACITY
> succeed as expected (DEC HSG80 / COMPAQ HSV*).

As James points out, this won't be quite the thing to do.


Sincerely,
    Lars Marowsky-Brée <lmb@suse.de>

-- 
High Availability & Clustering
SUSE Labs, Research and Development
SUSE LINUX AG - A Novell company

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