4.0.0 HP Polyserve Matrix Server Administration Guide (T5392-96052, March 2010)

Membership partitions
Matrix Server uses a set of membership partitions to control access to the SAN and
to store the mxds datastore and the device naming database. (The mxds datastore
contains cluster configuration information and the device naming database includes
the global device names for SAN disks imported into the cluster.) Typically the
membership partitions are created when you install Matrix Server. You can add,
replace, or repair membership partitions as necessary.
When a membership partition is placed under Matrix Server control, write access is
disabled to prevent accidental corruption from other applications.
Display the status of SAN ownership locks
Matrix Server uses a set of disk-based data structures called SANlocks to protect
filesystem integrity. If a problem causes a cluster to split into two or more network
partitions, the SANlocks ensure that only one of the resulting network partitions has
access to the SAN.
Each SANlock is stored in a membership partition. Before a cluster can begin
accessing the SAN, it must first acquire a majority of the SANlocks. The SANlocks
are acquired in order.
mxsanlk displays the status of the SANlock stored in each membership partition. It
can be used to determine whether any of the membership partitions need to be
repaired. Also, if a network partition occurs, mxsanlk can be used to determine
which network partition has control of the SAN.
When you invoke mxsanlk, it checks for the Storage Device Monitor Pulse (SDMP)
process. This process is responsible for grabbing and maintaining the locks on the
membership partitions. The SDMP administrator is the administrator for the cluster to
which the host belongs.
Following is some sample output from mxsanlk. The command was issued on host
99.10.30.3. There are three membership partitions.
# mxsanlk
This host: 99.10.30.3
This host’s SDMP administrator: 99.10.30.1
Membership Partition SANlock State
-------------------- -------------
/dev/rpsd/psd1p1 held by SDMP administrator
/dev/rpsd/psd2p1 held by SDMP administrator
/dev/rpsd/psd3p3 held by SDMP administrator
SAN maintenance242