You can enable SCSI-3 Persistent Reserve for the IBM® DB2® pureScale® Feature which
will provide faster fail-over support. SCSI-3 Persistent Reserve technology
allows for fast eviction and fencing of failed nodes in the cluster.
Before you begin
This task should be performed after you have installed
the DB2 pureScale Feature and
created your instance. If you already have GPFS™ installed and have a GPFS cluster running , for example, if you have DB2 pureScale Feature Fix
Pack 2 installed on your SLES hosts, then after moving to DB2 pureScale Feature Fix
Pack 3, you can perform this task at any time before using the DB2 pureScale environment.
You
need instance user and root user authority.
About this task
Not all disks support SCSI-3 Persistent Reserve on Linux.
Procedure
- Log in as the instance user.
- Stop the database manager by running the db2stop command.
- Log in as root user.
- Stop GPFS on all
hosts by running the db2cluster -cfs -stop -all command.
<DB2DIR>/db2cluster -cfs -stop -all
where DB2DIR represents
the installation location.
- Find the filesystems as the instance user:
coralm201:/home/madhusuk >db2cluster -cfs -list -filesystem
FILE SYSTEM NAME MOUNT_POINT
--------------------------------- -------------------------
fs /fs
- Find the disk info for that filesystem as the instance
user:
coralm201:/home/madhusuk >db2cluster -cfs -list -filesystem fs -disk
PATH ON LOCAL HOST OTHER KNOWN PATHS
--------------------------------- -------------------------
(*) /dev/sdc
- Find the information for that disk by running the tsprinquiry command
as root:
coralm201:# /usr/lpp/mmfs/bin/tsprinquiry sdc
IBM :VirtualDisk :0730
- Create the /var/mmfs/etc/prcapdevices file
on each host in the DB2 pureScale environment
and edit the file to add your disk. For example, using the output
from tsprinquiry command:
IBM:VirtualDisk:0730
- Tell GPFS to use
SCSI-3 Persistent Reserve by running the /usr/lpp/mmfs/bin/mmchconfig
usePersistentReserve=yes command.
- As the root user, start GPFS on
all nodes by running the db2cluster -cfs -start -all command.
- Once the GPFS filesystems
are mounted on all hosts, check that SCSI-3 Persistent Reserve has
been properly enabled by running the /usr/lpp/mmfs/bin/mmlsnsd
-X command on all machines and checking that "pr=yes" appears
in the Remarks column. For example:
coralm201:/usr/lpp/mmfs/bin # ./mmlsnsd -X
Disk name NSD volume ID Device Devtype Node name Remarks
---------------------------------------------------------------------------------
gpfs12nsd 091A5CBD4C6B8076 /dev/sdc generic coralm201.torolab.ibm.com pr=yes
- As the instance user, start the database manager by running
the db2start command.
Results
You can now use the DB2 pureScale Feature with
SCSI-3 Persistent Reserve.
DB2 10.5 for Linux, UNIX, and Windows