topic Re: EMC LUN presented to RHEL 5.3 in Operating System - Linux

EMC LUN presented to RHEL 5.3

AVV — Thu, 27 May 2010 07:13:18 GMT

Hi Gurus,

I have a rhel 5.3 64 bit linux server with vg00. Now we presented 6 LUNs to this from EMC storage. powermt display dev=all shows me the paths but can anyone help me to configure these disks on an LVM. How do we do pvcreate or on which path we have to. Please clarify me on this. I am attaching the output of powermt here with.

1. pvcreate on what path ???
2. how do we see the same from RHEL

Re: EMC LUN presented to RHEL 5.3

Prasanth V Aravind — Thu, 27 May 2010 07:42:53 GMT

>> 1. pvcreate on what path ???

you have to configure with Pseudo names.

like

pvcreate /dev/emcpowerf
pvcreate /dev/emcpowere

Gudluck
Prasanth

Re: EMC LUN presented to RHEL 5.3

Gerardo Arceri — Thu, 27 May 2010 14:09:17 GMT

Hi, pvcreate /dev/emcpowerXX should to the trick.

I strongly suggest you add the following filter line to /etc/lvm.conf so LVM uses the emcpower devices instead of sd*.
Make sure you comment out any existing "filter" lines.

filter = [ "a|^/dev/emcpower[a-z]*|","a|^/dev/cciss/.*|","r/.*/" ]

Re: EMC LUN presented to RHEL 5.3

AVV — Sun, 30 May 2010 16:11:47 GMT

Hi ,

I created the vg as said....but when I do a vgdisplay -v vg01, it shows me the the /dev/sdX path of the disk instead of /dev/emcpowerX . I did pvcreate/vgcreate on /dev/emcpowerX device file only. Pls assist.

Re: EMC LUN presented to RHEL 5.3

Matti_Kurkela — Mon, 31 May 2010 07:10:22 GMT

As Gerardo said, you should edit /etc/lvm/lvm.conf.

1.) In the "devices {" group near the beginning of the lvm.conf file, there is a line:

preferred_names = [ ]

Comment out the default line, and write in a custom filter instead. The result should look like this:

# preferred_names = [ ]
preferred_names = [ "^/dev/emcpower", "^/dev/mapper/", "^/dev/mapper/mpath", "/dev/[hs]d" ]

This will cause the LVM to prefer the EMC devices if it sees more than one PV with the same PV identifier (= the same LUN through different paths).

2.) Gerardo's filter line can achieve the same effect, but it assumes you are running on a Proliant system and have your vg00 on a SmartArray controller.

MK

Re: EMC LUN presented to RHEL 5.3

AVV — Wed, 05 Jan 2011 06:52:49 GMT

Thanks