From: Alexei_Roudnev (Alexei_Roudnev_at_exigengroup.com)
Date: Thu May 04 2006 - 08:23:59 CEST
Message-ID: <02c601c66f43$54595370$6f31a8c0@sjc.exigengroup.com> From: "Alexei_Roudnev" <Alexei_Roudnev@exigengroup.com> Date: Wed, 3 May 2006 23:23:59 -0700 Subject: Re: [suse-sles-e] Adding Disk on the fly
1) It depends of your driver. Many drivers have 'rescan' control variable
(see /proc/system or /sys file tree, I do not remember),
and when you write '1' into it driver see new disk.
2) Be adviced that you cannot resize disk when it is mounted - or to be
correct, you can resize it but system wil not see it until disk is unused
(it caused numerous problems with Oracle's ASM)
3) I had such problem in few cases and on a few servers and OS, and now I
use such approach:
- I create all LUN's in advance. For each task I create few reserved lun's,
making them as small as 20MB (it's easy on NetApp);
- the same with targets - it is better to have all possible targets exists
form beginning.
4) After it, I can resize disk when necessary. On Solaris, it works pretty
well if I run 'format' on this disk (system recognzie new size).
On Linux, it require rescan for HBA-s or 'rciscsi reload' for iscsi (reload
config and repeat search). IN many cases, I need to write '1' into
controller 'rescan' flag.
5) And it all driver dependent, so if it works for, say, iSCSI or Emulex
LP8000 (I am not sure), then it can be differntly for other HBA.
6) For disks with partitions, the same story - system see new disk size, but
partition user dont see it (I can recreate partition on the fly, in some
cases, but it is dangerous operation).
Anyway, I manage to work with it on all systems around (Linux, Solaris and
Windows). So, you can try - more likely you wil find a right way.
----- Original Message -----
From: "Denis Brown" <dsbrown@cyllene.uwa.edu.au>
To: <suse-sles-e@suse.com>
Sent: Wednesday, May 03, 2006 10:42 PM
Subject: Re: [suse-sles-e] Adding Disk on the fly
> At 01:09 PM 4/05/2006, Stephen Hughes wrote:
> >Hi Group,
> >In my environment here I have directly attached and SAN attached disk to
> >many servers. From time to time when the need arises I need to add more
> >disk to a server and find the only way to get my server to see the newly
> >assigned disk is to reboot.
> >
> >Is there a command/s that I can run that will pick up the newly assigned
> >disk with out having to reboot each time?
>
> Hello Stephen.
>
> One thought <insert usual disclaimers here> is to add the new disk
> specification to /etc/fstab, create a suitable mount point, then use the
> "mount" command.
>
> I see this as directly analogous to having (say) a floppy drive listed in
> fstab, and having a mount point assigned for it, then actually "attaching
> it" on demand using the mount command.
>
> It is probably a Good Idea (tm) to try this on a non-production machine
> first <big smile>
>
> Reading between the lines of your post though, perhaps you have tried this
> already. I must admit that normally disk specs in fstab and mount points
> are known quantities when a machine boots, so maybe the idea above is
invalid?
>
> HTH,
> Denis
>
>
>
>
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