A separate paging device is required for each LPAR that uses shared memory. One of the following device types can be used as a paging device:
-
- logical volume
- local disk
- SAN LUN
- iSCSI LUN
If two redundant paging virtual I/O servers are used, the paging devices must be SAN LUNs.
On our virtual I/O server ms03-vio1, the following physical volumes exist:
$ vios lspv ms03-vio1
PVNAME PVID VGNAME PVSTATE
hdisk0 0000000000cafe00 None -
hdisk1 0000000000cafe01 rootvg active
hdisk2 0000000000cafe02 rootvg active
hdisk3 0000000000cafe03 None -
hdisk4 0000000000cafe04 None -
$
The physical volumes hdisk3 and hdisk4 are each SAN LUNs, as the “vios lsdev” command shows:
$ vios lsdev ms03-vio1 hdisk3
NAME STATUS PHYSLOC PARENT DESCRIPTION
hdisk3 Available U78AA.001.VYRGU0Q-P1-C5-T1-W500507680130A1C4-L0 fscsi4 MPIO IBM 2145 FC Disk
$
$ vios lsdev ms03-vio1 hdisk4
NAME STATUS PHYSLOC PARENT DESCRIPTION
hdisk3 Available U78AA.001.VYRGU0Q-P1-C5-T1-W50050768013098BC-L0 fscsi4 MPIO IBM 2145 FC Disk
$
These SAN LUNs have not yet been used and are therefore perfect candidates as paging devices. There are 2 different but equivalent commands to add a paging device to a shared memory pool. Either the command “ms addpgdev” (add paging device) can be used:
$ ms addpgdev ms03 ms03-vio1 hdisk3
$
In addition to the managed system, the paging virtual I/O server and the paging device must be specified as arguments.
Alternatively, the somewhat shorter command “vios addpgdev” can be used:
$ vios addpgdev ms03-vio1 hdisk4
$
In which case only the paging virtual I/O server and the paging device have to be specified.
The shared memory pool now has the first two paging devices, as the command “ms lspgdev“ shows:
$ ms lspgdev ms03
REDUNDANT
MS_NAME DEVICE_NAME PAGING_VIOS_NAME STATE DEVICE_NAME PAGING_VIOS_NAME STATE SIZE TYPE LPAR_ID
ms03 hdisk3 ms03-vio1 Inactive - - - 51200 phys none
ms03 hdisk4 ms03-vio1 Inactive - - - 51200 phys none
$