[dm-devel] Rescan for new LUNs

[brem belguebli]

echo '- - -' > /sys/class/scsi_host/hostX/scan should be enough to
discover new Luns.

For some unknown reason, with some specific SAN storage  arrays (HP XP
in my case) , for newly SAN connected servers (new  zoning), it is not
enough.

I have to  issue lip (loop init) to my FC hosts

echo 1 > /sys/class/fc_host/hostX/issue_lip

This lip command can be destructive(and is asynchronous) , so use it
only before first SAN discovery. After that as I said, scan is enough.

Brem

2010/7/6 Bryn M. Reeves <bmr at redhat.com>:
> On 07/01/2010 06:43 PM, Allen, Jack wrote:
>> That sounds more like what I am looking for. But I can not find the script on my
>> system or what provides it via "yum provides". I am running RHEL 5.5.
>> We have customers that run an Application that needs to be up 24*7. They some
>> times need to add additional storage and when attached to a SAN they would
>> prefer not to have to take the Application down and reboot the system just to
>> make the new LUNs be seen by the system.
>> -----
>> Jack Allen
>>
>> --------------------------------------------------------------------------------
>> *From:* dm-devel-bounces at redhat.com [mailto:dm-devel-bounces at redhat.com] *On
>> Behalf Of *Oren Held
>> *Sent:* Thursday, July 01, 2010 2:55 AM
>> *To:* dm-devel at redhat.com
>> *Subject:* Re: [dm-devel] Rescan for new LUNs
>>
>> It's not an easy process.
>>
>> The rescan-scsi-bus.sh script was added in recent RHEL5 updates, already in old
>> SLES. I guess it's becoming kind of a standard.
>
> The script was originally written by Kurt Garloff but it's been included
> in the sg3_utils tarball for years:
>
> Changelog for sg3_utils-0.99 [20020317]
> ----------------------------
>  - add 'fua' and 'sync' arguments to sg_dd, sgp_dd and sgm_dd
>  - improve sg_inq, add "-cl" and "-36" arguments
>  - add sg_modes + sg_logs for MODE SENSE and LOG SENSE queries
>  - add rescan-scsi-bus.sh [Kurt Garloff] to archive director
>
> It's only recently been included in the build for RHEL packages though
> (5.3 iirc) - just yum install sg3_utils to get the script on a RHEL-5
> system (as well as other useful bits like sg_map and friends).
>
> The script may work for some combinations of storage and controller in
> earlier RHEL versions but isn't included in the distribution and is not
> always perfectly reliable.
>
> If you need to add/remove storage on these older releases you can use
> the simple scsi-add/remove-single-device interface via /proc/scsi/scsi.
>
> If you have access to the Red Hat knowledge base (RHN login) there's an
> article that explains the options on RHEL systems:
>
> https://access.redhat.com/kb/docs/DOC-3942
>
> And there's the RHEL5 Online Storage Reconfiguration Guide here:
>
> http://tinyurl.com/ya6wmce [www.redhat.com]
>
> That documents these interfaces as well as the FC and iSCSI APIs and
> their relation to other components such as multipath.
>
> Regards,
> Bryn.
>
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