HP OpenVMS System Manager's Manual, Volume 2:...

Managing DECdtm Services

Planning for a DECnet-Plus Network

Monitoring Transaction Performance

Creating Transaction Logs  

Removing a node from a cluster after you have created the transaction logs can lead to data corruption. For instructions on how to remove a node safely, see Removing a Node.

1. For each node, decide the size and location of the transaction log, using the guidelines in Planning Transaction Logs. Remember that the disks must have enough contiguous space to hold the transaction logs.
2. If you are in a cluster environment, make sure that the disks on which you want to create the transaction logs are mounted clusterwide.
3. Decide in which directories you want to create the transaction logs. You may want to create new directories for the transaction logs.
4. Define SYS$JOURNAL to point to the directories in which you want to create the transaction logs: DEFINE/SYSTEM/EXECUTIVE_MODE SYS$JOURNAL dirspec[,...]where dirspec is the full specification of a directory in which you want to create one or more transaction logs. List all the directories that will contain transaction logs. You can list the directories in any order.
   
   In a cluster environment, use SYSMAN to define SYS$JOURNAL clusterwide.
5. Edit the SYS$MANAGER:SYLOGICALS.COM command procedure to include the SYS$JOURNAL definition.
   
   If you created node-specific versions of SYLOGICALS.COM, edit all the versions.
6. Create one transaction log for each node, using LMCP's CREATE LOG command: CREATE LOG [/SIZE=size] dirspecSYSTEM$node.LM$JOURNAL where:

   size	is the size of the transaction log in blocks. By default, the size of the transaction log is 4000 blocks.
   dirspec	is the full specification of the directory in which you want to create the transaction log.
   node	is the name of the node.

   
   

7. Make sure DECdtm services are enabled as follows:

   Step	Action
   a.	Check whether the logical SYS$DECDTM_INHIBIT is defined: $ SHOW LOGICAL SYS$DECDTM_INHIBIT
   b.	Is SYS$DECDTM_INHIBIT defined? Yes   DECdtm services are disabled. Enable DECdtm services by following the instructions in Disabling DECdtm Services. No   DECdtm services are enabled.

   
   

Example

This example shows how to create transaction logs in an OpenVMS Cluster that consists of two nodes whose SCSNODE names are BLUE and RED. Neither node has a node-specific version of SYLOGICALS.COM.

Decide the size and location of the transaction logs:

Node	Size of Log (in Blocks)	Disk
BLUE	5000	DUA1
RED	4000	DUA2

Mount the disks clusterwide:

$ MOUNT/CLUSTER/SYSTEM DUA1: LOG1
$ MOUNT/CLUSTER/SYSTEM DUA2: LOG2

$ CREATE/DIRECTORY DISK$LOG1:[LOGFILES]
$ CREATE/DIRECTORY DISK$LOG2:[LOGFILES]

$ RUN SYS$SYSTEM:SYSMAN
SYSMAN> SET ENVIRONMENT/CLUSTER
SYSMAN> DO DEFINE/SYSTEM/EXECUTIVE_MODE SYS$JOURNAL - 
_SYSMAN> DISK$LOG1:[LOGFILES], DISK$LOG2:[LOGFILES]
SYSMAN> EXIT

$ !
$ DEFINE/SYSTEM/EXECUTIVE_MODE SYS$JOURNAL DISK$LOG1:[LOGFILES], -
_$DISK$LOG2:[LOGFILES]
$ !

$ RUN SYS$SYSTEM:LMCP
LMCP> CREATE LOG/SIZE=5000 DISK$LOG1:[LOGFILES]SYSTEM$BLUE.LM$JOURNAL
LMCP> CREATE LOG DISK$LOG2:[LOGFILES]SYSTEM$RED.LM$JOURNAL
LMCP> EXIT

$ SHOW LOGICAL SYS$DECDTM_INHIBIT
%SHOW-S-NOTRAN, no translation for logical name SYS$DECDTM_INHIBIT

Planning for a DECnet-Plus Network

Monitoring Transaction Performance