Topics: AIX, Storage, System Administration

Allocating shared storage to VIOS clients

The following is a procedure to add shared storage to a clustered, virtualized environment. This assumes the following: You have a PowerHA cluster on two nodes, nodeA and nodeB. Each node is on a separate physical system, and each node is a client of a VIOS. The storage from the VIOS is mapped as vSCSI to the client. Client nodeA is on viosA, and client nodeB is on viosB. Futhermore, this procedure assumes you're using SDDPCM for multi-pathing on the VIOS.

First of all, have your storage admin allocate and zone shared LUN(s) to the two VIOS. This needs to be one or more LUNs that is zoned to both of the VIOS. This procedure assumes you will be zoning 4 LUNs of 128 GB.

Once that is completed, then move to work on the VIOS:

SERVER: viosA

First, gather some system information as user root on the VIOS, and save this information to a file for safe-keeping.

# lspv
# lsdev -Cc disk
# /usr/ios/cli/ioscli lsdev -virtual
# lsvpcfg
# datapath query adapter
# datapath query device
# lsmap -all
Discover new SAN LUNs (4 * 128 GB) as user padmin on the VIOS. This can be accomplished by running cfgdev, the alternative to cfgmgr on the VIOS. Once that has run, identify the 4 new hdisk devices on the system, and run the "bootinfo -s" command to determine the size of each of the 4 new disks:
# cfgdev
# lspv
# datapath query device
# bootinfo -s hdiskX
Change PVID for the disks (repeat for all the LUNs):
# chdev -l hdiskX -a pv=yes
Next, map the new LUN from viosA to the nodeA lpar. You'll need to know 2 things here: [a] What vhost adapter (or "vadapter) to use, and [b] what name to give the new device (or "virtual target device"). Have a look at the output of the "lsmap -all" command that you ran previously. That will provide you information on the current naming scheme for the virtual target devices. Also, it will show you what vhost adapters already exist, and are in use for the client. In this case, we'll assume the vhost adapter is vhost0, and there are already some virtual target devices, called: nodeA_vtd0001 through nodeA_vtd0019. The new four LUNs therefore will be named: nodeA_vtd0020 through nodeA_vtd0023. We'll also assume the new disks are numbered hdisk44 through hdisk47.
# mkvdev -vdev hdisk44 -vadapter vhost0 -dev nodeA_vtd0020
# mkvdev -vdev hdisk45 -vadapter vhost0 -dev nodeA_vtd0021
# mkvdev -vdev hdisk46 -vadapter vhost0 -dev nodeA_vtd0022
# mkvdev -vdev hdisk47 -vadapter vhost0 -dev nodeA_vtd0023
Now the mapping of the LUNs is complete on viosA. You'll have to repeat the same process on viosB:

SERVER: viosB

First, gather some system information as user root on the VIOS, and save this information to a file for safe-keeping.
# lspv
# lsdev -Cc disk
# /usr/ios/cli/ioscli lsdev -virtual
# lsvpcfg
# datapath query adapter
# datapath query device
# lsmap -all
Discover new SAN LUNs (4 * 128 GB) as user padmin on the VIOS. This can be accomplished by running cfgdev, the alternative to cfgmgr on the VIOS. Once that has run, identify the 4 new hdisk devices on the system, and run the "bootinfo -s" command to determine the size of each of the 4 new disks:
# cfgdev
# lspv
# datapath query device
# bootinfo -s hdiskX
No need to set the PVID this time. It was already configured on viosA, and after running the cfgdev command, the PVID should be visible on viosB, and it should match the PIVIDs on viosA. Make sure this is correct:
# lspv
Map the new LUN from viosB to the nodeB lpar. Again, you'll need to know the vadapter and the virtual target device names to use, and you can derive that information by looking at the output of the "lsmap -all" command. If you've done your work correctly in the past, the naming of the vadapter and the virtual target devices will probably be the same on viosB as on viosA:
# mkvdev -vdev hdisk44 -vadapter vhost0 -dev nodeB_vtd0020
# mkvdev -vdev hdisk45 -vadapter vhost0 -dev nodeB_vtd0020
# mkvdev -vdev hdisk46 -vadapter vhost0 -dev nodeB_vtd0020
# mkvdev -vdev hdisk47 -vadapter vhost0 -dev nodeB_vtd0020
Now that the mapping on both the VIOS has been completed, it is time to move to the client side. First, gather some information about the PowerHA cluster on the clients, by running as root on the nodeA client:
# clstat -o
# clRGinfo
# lsvg |lsvg -pi
Run cfgmgr on nodeA to discover the mapped LUNs, and then on nodeB:
# cfgmgr
# lspv
Ensure that the disk attributes are correctly set on both servers. Repeat the following command for all 4 new disks:
# chdev -l hdiskX -a algorithm=fail_over -a hcheck_interval=60 -a queue_depth=20 -a reserve_policy=no_reserve
Now you can add the 4 new added physical volumes to a shared volume group. In our example, the shared volume group is called sharedvg, and the newly discovered disks are called hdisk55 through hdisk58. Finally, the concurrent resource group is called concurrent_rg.
# /usr/es/sbin/cluster/sbin/cl_extendvg -cspoc -g'concurrent_rg' -R'nodeA' sharedvg hdisk55 hdisk56 hdisk57 hdisk58
Next, you can move forward to creating logical volumes (and file systems if necessary), for example, when creating raw logical volumes for an Oracle database:
# /usr/es/sbin/cluster/sbin/cl_mklv -TO -t raw -R'nodeA' -U oracle -G dba -P 600 -y asm_raw5 sharedvg 1023 hdisk55
# /usr/es/sbin/cluster/sbin/cl_mklv -TO -t raw -R'nodeA' -U oracle -G dba -P 600 -y asm_raw6 sharedvg 1023 hdisk56
# /usr/es/sbin/cluster/sbin/cl_mklv -TO -t raw -R'nodeA' -U oracle -G dba -P 600 -y asm_raw7 sharedvg 1023 hdisk57
# /usr/es/sbin/cluster/sbin/cl_mklv -TO -t raw -R'nodeA' -U oracle -G dba -P 600 -y asm_raw8 sharedvg 1023 hdisk58
Finally, verify the volume group:
# lsvg -p sharedvg
# lsvg sharedvg
# ls -l /dev/asm_raw*
If necessary, these are the steps to complete, if the addition of LUNs has to be backed out:
  1. Remove the raw logical volumes (using the cl_rmlv command)
  2. Remove the added LUNs from the volume group (using the cl_reducevg command)
  3. Remove the disk devices on both client nodes: rmdev -dl hdiskX
  4. Remove LUN mappings from each VIOS (using the rmvdev command)
  5. Remove the LUNs frome each VIOS (using the rmdev command)