Discover new SAN devices on DMM

[MSwift]

on RHEL 5 when a new SAN disk is added how would i discover it?

Thanks

Mike.

[Matti_Kurkela · Accepted solution]

RedHat has written an "Online Storage Reconfiguration Guide" for exactly this purpose:

http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Online_Storage_Reconfiguration_Guide/index.html

Please see Chapter 9: Scanning Storage Interconnects.

MK

[Alzhy]

Generally after presenting disks to a SAN connected LINUX Server - you do the following:

SCAN:
for hba in `ls -d /sys/class/fc_host/host*`;do
FCHOST=`basename $hba`

echo "Scanning $FCHOST"
echo "- - -" > /sys/class/scsi_host/${FCHOST}/scan
done

Then:

multipath -ll

If you need to give your Disks friednlier names like /dev/mapper/EVA08_DB_dsk001 - then add/edit www alias entries in /etc/multipath.conf and do "multipath -v2". Finish off with "multipath -ll" and check if mapper /path entries are present in /dev/mapper and /dev/mpath.

Finish off with using the disk -- paritioning it wholly or whatever are your standards...


The abobve assumes you do not have the Array's proprietary MultiPathing solution engaged -- like PowerPath from EMC or HDLM from Hitachi, etc...

HTH.

[MSwift]

I tried this. The issue_lip command logs into /var/log/messages but the

echo "- - -" > /sys/class/scsi_host/

command does not log anything to the messages. I am not saying that it is not scanning, but it does not log anything.

Just an observation.

Thanks

Mike.

[MSwift]

Again these are qlogic fc's. would that make a difference??

Mike

[Alzhy]

Nope.. it works for both Emulex and Qlogic HBAs (likely Brocade's too)...

We use to use Qloic and Emulex native sacndisks tools but opted for just the simple...

The disks newly discovered are actually logged... if you do a "dmesg" afterwards -- you will see the discoveries made.

If you are using HP StorageWorks Arrays -- EVA, P or XP series, etc... -- please be aware taht it is advisable that you install the HP Device Multipather kit as it gives you the correct /etc/multipath.conf