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

Managing DECdtm Services

Creating Transaction Logs

Checking Whether a Transaction Log Is Too Small

Monitoring Transaction Performance  

How to Perform This Task

1. Monitor transactions,using the MONITOR TRANSACTION command:MONITOR TRANSACTION/SUMMARY[=file-spec]/ENDING=time/NODE=(nodename,...)where:

   file-spec	is the file specificationof the summary file. Information about transactions is summarizedand recorded in the summary file. If you omit the file specification,the information is recorded in MONITOR.SUM in your default directory.
   time	is the time that the monitoringsession ends.
   nodename	is the name of a node. In an OpenVMSCluster, list all the nodes in the cluster.

   
   

   For the best results, monitor transactions for a day at atime.
   
   You can monitor transactions in batch mode by including the MONITOR TRANSACTION command in a command procedure.
   
   For a full description of the MONITOR TRANSACTION command, refer to the HP OpenVMS System Management Utilities Reference Manual.

2. Examine the summary file.
   
   The summary file contains values for a number of differentdata items. Note the following values for each node:
   • Average end rate. This is the averagenumber of transactions completed per second.
   
   
   
   • Average completion rates. These are the averagenumbers of transactions completed in the following times:

     Less than 1 second

     Between 1 and 2 seconds

     Between 2 and 3 seconds

     Between 3 and 4 seconds

     Between 4 and 5 seconds

     More than 5 seconds

   Make a note of these values.
3. Compare the results from this monitoring sessionwith the results from previous sessions.
   
   For the same work load, the rate and duration of transactionsshould remain about the same. Indications of performance deteriorationare:
   • The average end rate decreases
   
   
   
   • The average duration increases
     
     To find out whether the average duration of transactions hasincreased, compare the average completion rates. If a greater proportionof the transactions takes longer to complete, the average durationof transactions has increased.
   Note any trends over a number of monitoring sessions. Variationsfrom one monitoring session to the next are probably due to variationsin work load.
   
   If you suspect that transaction performance has deterioratedon any node, check whether its transaction log is too small (see Checking Whether a Transaction Log Is Too Small).
   
   If the transaction log is big enough, but transaction performancestill deteriorates, tuning the system might be necessary. Referto OpenVMS Performance Management for information about tuning your system.

Example

This example shows how to monitor transaction performanceon an OpenVMS Cluster that consists of two nodes whose SCSNODE namesare BLUE and RED.

Monitor transactions on nodes BLUE and RED for one day:

$ MONITOR TRANSACTION/SUMMARY=DISK$LOG1:[LOGFILES]TRANSACTIONS.SUM -_$ /ENDING="+1-"/NODE=(BLUE,RED) 

                   DISTRIBUTED TRANSACTION STATISTICS                             on node BLUE         From: 16-OCT-2000 14:23:51                                SUMMARY           To:   17-OCT-2000 14:23:51                                   CUR        AVE        MIN        MAX Start Rate                       49.02      43.21      31.30      49.02Prepare Rate                     48.70      43.23      30.67      48.70One Phase Commit Rate             0.00       0.00       0.00       0.00Total Commit Rate                48.70      43.19      31.30      48.70Abort Rate                        0.00       0.00       0.00       0.00End Rate                         48.70      43.19      31.30      48.70Remote Start Rate                 0.00       0.00       0.00       0.00Remote Add Rate                   0.00       0.00       0.00       0.00 Completion Rate    0-1           21.42      13.57       0.63      21.42 by Duration       1-2           25.97      29.15      24.59      33.87 in Seconds        2-3            1.29       0.47       0.00       4.47                   3-4            0.00       0.00       0.00       0.00                   4-5            0.00       0.00       0.00       0.00                    5+            0.00       0.00       0.00       0.00                               SUMMARIZING DISTRIBUTED TRANSACTION STATISTICS		                                on node RED          From: 16-OCT-2000 14:23:52                                SUMMARY           To:   17-OCT-2000 14:23:52 ...

• Average end rate.
  
  For node BLUE, the average end rate is 43.19 transactionsper second.



• Average completion rates.
  
  For node BLUE, the average completion rates are as follows:
  
  

  13.57 transactionscompleted in 0 to 1 seconds

  29.15 transactions completed in 1 to 2 seconds

  0.47 transactions completed in 2 to 3 seconds

Compare the results from this monitoring session to thoseof previous sessions:

Session	End Rate	CompletionRates
		0-1 Secs	1-2 Secs	2-3 Secs
Session	End Rate	CompletionRates
		0-1 Secs	1-2 Secs	2-3 Secs
June	42.13	12.98	28.13	1.02
July	38.16	10.35	25.80	2.01
August	43.19	13.57	29.15	0.47

The results for node BLUE show no signs of deteriorating performance.

Creating Transaction Logs

Checking Whether a Transaction Log Is Too Small