topic Qlogic with EVA disk in Operating System - Linux

Qlogic with EVA disk

Idham — Mon, 02 Mar 2009 03:19:16 GMT

Hi,

I've installed 2 Qlogic card coonect to EVA storage...I allocated 5 disk from EVA and use the Qlogic driver form hp. But after reboot the server,the Linux OS appear to use the last group of disk /dev/sfa...not like normal setting which is /dev/sda. Is it something to do with the SCSI card? How to change back to normal?

[root@glstream2 ~]# lssd
sda 0,0,0,1 HP HSV200 6110 <-SAN disk
sdb 0,0,0,2 HP HSV200 6110 <-SAN disk
sdc 0,0,0,3 HP HSV200 6110 <-SAN disk
sdd 0,0,0,4 HP HSV200 6110 <-SAN disk
sde 0,0,0,5 HP HSV200 6110 <-SAN disk
sdf 2,2,0,0 DELL PERC 6/i 1.21

[root@glstream1 sysconfig]# fdisk -l

Device Boot Start End Blocks Id System
/dev/sda1 1 1011 1048376+ 83 Linux

Device Boot Start End Blocks Id System
/dev/sdb1 1 1011 1048376+ 83 Linux

Device Boot Start End Blocks Id System
/dev/sdc1 1 39162 314568733+ 83 Linux

Device Boot Start End Blocks Id System
/dev/sdd1 1 39162 314568733+ 83 Linux

Device Boot Start End Blocks Id System
/dev/sde1 1 19581 157284351 83 Linux

Device Boot Start End Blocks Id System
/dev/sdf1 * 1 13 104391 83 Linux
/dev/sdf2 14 17769 142625070 8e Linux LVM

Re: Qlogic with EVA disk

Steven E. Protter — Mon, 02 Mar 2009 11:27:53 GMT

Shalom,

What you encountered is normal.

First disk discovered gets sda, then sdb right on down the line.

If you reinstall the OS fresh, you would start over.

SEP

Re: Qlogic with EVA disk

Ivan Ferreira — Mon, 02 Mar 2009 11:28:58 GMT

Linux will name the disks in the order that is detected. Probably, you can't change, anyway, you don't have to change this.

This is why you use LABELS or UUID to mount file systems in fstab, or you can create persistent binding using udev.

Re: Qlogic with EVA disk

Steven McCoy — Thu, 05 Mar 2009 15:53:29 GMT

Hey Idham,

You could use device-mapper-multipath to assign devices via WWID and alias them to friendly names.

Check out the contents of '/dev/disk/by-id/' and see if the WWIDs are shown up there:

ls -l /dev/disk/by-id/

Then populate the '/etc/multipath.conf' file similar to below (with a separate 'multipath' entry for each WWID):

-----------------------------------------------
defaults {
user_friendly_names yes
}
blacklist {
wwid 26353900f02796769
devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
devnode "^hd[a-z]"
devnode "^cciss!c[0-9]d[0-9]*[p[0-9]*]"
}
multipaths {
multipath {
wwid 3600508b400013cf32341b00000620000
alias myname1
}
multipath {
wwid 3600508b4113013cf32341b00000620000
alias myname2
}
}
-----------------------------------------------

Restart the multipath daemon:

/etc/init.d/multipathd restart

Then try detecting the devices:

multipath -v2
multipath -ll

If your LUNs do not show up, consider taking a look at the '/usr/share/doc/device-mapper-multipath*/multipath.conf.defaults' file and adding a devices section for your SAN. Something similar to:

---------------------------------------------
devices {
device {
vendor "(COMPAQ|HP)"
product "HSV(1|2).*"
getuid_callout "/sbin/scsi_id -g -u -s /block/%n"
prio_callout "/sbin/mpath_prio_alua %n"
features "0"
hardware_handler "0"
path_grouping_policy group_by_prio
failback immediate
rr_weight uniform
no_path_retry 60
rr_min_io 1000
path_checker tur
}

}
---------------------------------------------

Don't forget to re-run 'multipath -v2' if you make any changes to the config file.

HTH

Re: Qlogic with EVA disk

Steven McCoy — Thu, 05 Mar 2009 15:55:52 GMT

The resulting devices you'll want to mount (or create logical volumes on) are:

/dev/mapper/myname1
/dev/mapper/myname2