The process of sharing physical volumes (PV) across multiple logical partitions (LPARs)

Share the same PV across multiple LPARs

This article provides a process for sharing the same PV across multiple lpars.

These PV can:

1. On the Ibm®power systems™ server, these servers are assigned to the virtual I/O server (VIOS).

2. From the storage Area network (SAN), allocated to VIOS.

In this example, we shared 4 PV (HDISK5, Hdisk6, Hdisk7, and Hdisk8) on 3 LPARs (SYS1, Sys2, and SYS3).

Log on to VIOS using the Padmin ID and password.

Login Id:padmin

Login Password: padmin password

Last failed Login: Thu Apr 1 00:12:40 CDT on/dev/vty0

Last login: Sat 00:03:49 CDT on/dev/vty0

To perform administrative tasks, run the oem_setup_env command.

$ oem_setup_env

#

Check physical volume IDs and generate new IDs

Use the LSPV command to check the disk's physical volume identifier (PVID).

#lspv

If you notice that a disk is not PVID or there is a duplicate PVID, you need to clear the PVID and set PVID again.

Clear PVID:

#chdev-L hdisk5-a pv=clear#chdev-l hdisk6-a pv=clear#chdev-l hdisk7-a pv=clear#chdev-l hdisk8-a pv=clear

Get PV PVID again:

#chdev-L hdisk5-a pv=yes#chdev-l hdisk6-a pv=yes#chdev-l hdisk7-a pv=yes#chdev-l hdisk8-a pv=yes

Change retention Policy

Because we need to assign the same disk to multiple lpars, change the retention policy to No. Otherwise, we cannot allocate them.

To change a retention policy:

#chdev-L hdisk5-a reserve_policy=no_reserve#chdev-l hdisk6-a reserve_policy=no_reserve#chdev-l hdisk7-a reserve_ Policy=no_reserve#chdev-l hdisk8-a Reserve_policy=no_reserve

Now exit from Oem_setup_env.

assigning Disks to LPARs

Map (assign) the disk to each LPAR.

The VHOST4 adapter is assigned to the Sys1 LPAR, and all disks are assigned to the same virtual Vscsi (Sgt Computer system Interface, small computer system interface) adapter Vhost4.

mkvdev-f-vdev hdisk5-vadapter vhost4-dev sys1_hdisk5mkvdev-f-vdev hdisk6-vadapter vhost4-dev sys1_hdisk6mkvdev-f -vdev hdisk7-vadapter vhost4-dev sys1_hdisk7mkvdev-f-vdev hdisk8-vadapter vhost4-dev sys1_hdisk8

The VHOST5 adapter is assigned to the Sys2 LPAR, and all disks are assigned to the same virtual SCSI adapter Vhost5.

Mkvdev-f-vdev hdisk5-vadapter vhost5-dev sys2_hdisk5mkvdev-f-vdev hdisk6-vadapter Vhost5-dev- Vdev hdisk7-vadapter vhost5-dev sys2_hdisk7mkvdev-f-vdev hdisk8-vadapter vhost5-dev sys2_hdisk8

The VHOST6 adapter is assigned to the SYS3 LPAR, and all disks are assigned to the same virtual SCSI adapter Vhost6.

mkvdev-f-vdev hdisk5-vadapter vhost6-dev sys3_hdisk5mkvdev-f-vdev hdisk6-vadapter vhost6-dev sys3_hdisk6mkvdev-f -vdev hdisk7-vadapter vhost6-dev sys3_hdisk7mkvdev-f-vdev hdisk8-vadapter vhost6-dev sys3_hdisk8

Now log on to each LPAR and run the cfgmgr command

Use the LSPV command to check the PVID of the disk.

PVID should be the same in all LPARs.

General purpose of this setting

This type of setting is primarily used in a clustered environment.

Because I belong to an IT team, I have configured this setting for the following scenario:

1. IBM aix® Server cluster environment

2. When you need to use the same storage for the IBM db2® clustered server

3. Cluster or IBM powerha® environment, when we use the same PV in the active-standby scenario to implement failover