RHEL5.2 Multipathing with EVA4400

[Jason Ng Teng Po]

Hi,

I followed the setup guide at this url http://h20000.www2.hp.com/bizsupport/TechSupport/SoftwareDescription.jsp?lang=en&cc=us&prodTypeId=12169&prodSeriesId=3559651&swItem=co-61880-1&prodNameId=3559652&swEnvOID=4006&swLang=13&taskId=135&mode=4&idx=0

and the RHEL5.2 still shows 2x20gb eventhough I present it only 1 vdisk 20gb.

I had install the lpfc and fiberutils drivers for the emulex FC2142SR.

Can any one confirmed with me anyone out there got it working?

Do I need to install the HPDMmultipath-4.0.0? Because that one is only for RHEL5.1

[Court Campbell · Accepted solution]

Your system should see the disk twice. You use dm multipath so that you have one device file that provides access to the two paths to the disk. Once setup, you use the command

multipath -ll

to see your multipathed devices.

[Steven E. Protter]

Shalom,

This may be cleared up by making a new ramdisk image of your system.


example.

cd /boot
mv initrd-....img to initrd-....img.orig

mkinitrd

mkinitrd initrd-2.6.9-42.0.3.ELsmp.img 2.6.9-42.0.3.ELsmp


Do this after clean installation of emulex drivers.

SEP

[Jason Ng Teng Po]

Court,

After I present, I will see /dev/sda[20gb] and /dev/sdb[20gb]. After I do the multipathing, it came up another /dev/dm-2

is the /dev/dm-2 the one I need to initialize, make as new volgroup, create logical disk, and mount it to a folder?

[Court Campbell]

You got it.

[Court Campbell]

If you run mulitpath -ll you should see an mpathX. You'll see something like this:

multipath -ll
mpath2 (3600508b400104fe60000c00000070000)
[size=300 GB][features="1 queue_if_no_path"][hwhandler="0"]
\_ round-robin 0 [prio=100][active]
\_ 3:0:0:1 sdc 8:32 [active][ready]
\_ 4:0:1:1 sdf 8:80 [active][ready]
\_ round-robin 0 [prio=20][enabled]
\_ 3:0:1:1 sdd 8:48 [active][ready]
\_ 4:0:0:1 sde 8:64 [active][ready]

In this case this is mpath2. If I do an ll on /dev/mpath/mpath2 it will show which dm -X file it is linked to.

[Jason Ng Teng Po]

Hi Court,

What is recommended multipath policy for EVA4400?

In the document says group_by_prio. Does this policy provides the failover controler?

[Court Campbell]

The defaults are group_by_prio and the selector of round-robin. grop_by_prio groups disks based on priority. And round-robin will be the way dm uses the paths. It shold round-robin over the hba's to the controllers. And it should provide failover to use another path if one fails. You could use the command "watch -d iostat" to the the disk usage.

[Jason Ng Teng Po]

Hi Court,

Thanks for your advices. Much appericiate.

[Court Campbell]

Here is what is in my multipath.conf file:

# For EVA3000(HSV101) / EVA5000(HSV111) / EVA4000/6000 / EVA8000

device {
vendor "HP|COMPAQ"
product "HSV1[01]1 \(C\)COMPAQ|HSV[23][01]0"
path_grouping_policy group_by_prio
getuid_callout "/sbin/scsi_id -g -u -s /block/%n"
path_checker tur
path_selector "round-robin 0"
prio_callout "/sbin/mpath_prio_alua /dev/%n"
rr_weight uniform
failback immediate
hardware_handler "0"
no_path_retry 12
}

[Court Campbell]

Also, if you don't mind, a few points wouldn't hurt.

[Jason Ng Teng Po]

I was about to assign then you replied :)