The predefined situations in this category monitor the status of VSAM data sets. The description and formula for these situations follow.
Use LSR pools so that strings and buffers are shared for all files. LSR can greatly reduce the total I/O and CPU usage in your system. If there are no evident problems, consider increasing the number of strings in the FCT.
Formula
If the value of the attribute VSAM_Strings_Percent_in_Use is greater than 85 and the value of the attribute VSAM_Strings_Percent_in_Use is less than or equal to 100
Use LSR pools so that strings and buffers are shared for all files. LSR can greatly reduce the total I/O and CPU usage in your system. If there are no evident problems, consider increasing the number of strings in the FCT.
Formula
If the value of the attribute VSAM_Strings_Percent_in_Use is greater than 100
Consider using LSR pools so that strings and buffers are shared by files. LSR can greatly reduce the total I/O and CPU usage in your CICS region. Use the Transaction Analysis report to determine whether there is a problem that is preventing tasks from completing in a timely manner. For example, tasks can be waiting for an enqueue or CICS can be short-on-storage. If you determine that there is no bottleneck and the problem persists, consider increasing the number of VSAM strings.
Formula
If the value of the attribute VSAM_String_Waits is greater than 3 and the value of the attribute VSAM_String_Waits is less than or equal to 7
Consider using LSR pools so that strings and buffers are shared by files. LSR can greatly reduce the total I/O and CPU usage in your CICS region. Use the Transaction Analysis report to determine whether there is a problem that is preventing tasks from completing in a timely manner. For example, tasks can be waiting for an enqueue or CICS can be short- on-storage. If you determine that there is no bottleneck and the problem persists, consider increasing the number of VSAM strings.
Formula
If the value of the attribute VSAM_String_Waits is greater than 7
If a higher level of activity against the data set has increased string waits, consider increasing the number of strings that are defined for the named data set. Use LSR pools so that files share buffers and strings. LSR can reduce the total I/O and CPU usage in your CICS system. If a data set is defined in an LSR pool, demand for strings can be reduced as a result of successful buffer lookasides.
Formula
If the value of the attribute Percent_Waits_Versus_I/O is greater than 3 and the value of the attribute Percent_Waits_Versus_I/O is less than or equal to 5
If a higher level of activity against the data set has increased string waits, consider increasing the number of strings that are defined for the named data set. Use LSR pools so that files share buffers and strings. LSR can reduce the total I/O and CPU usage in your CICS system. If a data set is defined in an LSR pool, demand for strings can be reduced as a result of successful buffer lookasides.
Formula
If the value of the attribute Percent_Waits_Versus_I/O is greater than 5
Reorganize the file as soon as possible. If splits continue to occur at a frequent rate, consider redefining the FREESPACE options to reduce split activity.
Formula
If the value of the attribute Data_CA_Splits_in_Last_Hour is greater than 1 and the value of the attribute Data_CA_Splits_in_Last_Hour is less than or equal to 2
Reorganize the file as soon as possible. If splits continue to occur at a frequent rate, consider redefining the FREESPACE options to reduce split activity.
Formula
If the value of the attribute Data_CA_Splits_in_Last_Hour is greater than 2
Continued CI splits indicate that a CA split can occur soon. CA splits can take a long time to complete, so try to reorganize the file before the CA split occurs. Large numbers of CI splits can indicate that FREESPACE can have to be adjusted.
Formula
If the value of the attribute Data_CI_Splits_in_Last_Hour is greater than 4 and the value of the attribute Data_CI_Splits_in_Last_Hour is less than or equal to 10
Continued CI splits indicate that a CA split can occur soon. CA splits can take a long time to complete, so try to reorganize the file before the CA split occurs. Large numbers of CI splits can indicate that FREESPACE can have to be adjusted.
Formula
If the value of the attribute Data_CI_Splits_in_Last_Hour is greater than 10
Consider increasing the primary allocation for the data component of the file.
Formula
If the value of the attribute Data_Extents_in_Last_Hour is greater than 1 and the value of the attribute Data_Extents_in_Last_Hour is less than or equal to 2
Consider increasing the primary allocation for the data component of the file.
Formula
If the value of the attribute Data_Extents_in_Last_Hour is greater than 2
Reorganize the file as soon as possible. If splits continue to occur at a frequent rate, consider redefining the FREESPACE options to reduce split activity.
Formula
If the value of the attribute Index_CA_Splits_in_Last_Hour is greater than or equal to 1
Reorganize the file as soon as possible. If splits continue to occur at a frequent rate, consider redefining the FREESPACE options to reduce split activity.
Formula
If the value of the attribute Index_CA_Splits_in_Last_Hour is greater than or equal to 1
Continued CI splits indicate that a CA split can occur soon. CA splits can take a long time to complete, so try to reorganize the file before the CA split occurs. Large numbers of CI splits can indicate that FREESPACE can have to be adjusted.
Formula
If the value of the attribute Index_CI_Splits_in_Last_Hour is greater than or equal to 1
Continued CI splits indicate that a CA split can occur soon. CA splits can take a long time to complete, so try to reorganize the file before the CA split occurs. Large numbers of CI splits can indicate that FREESPACE can have to be adjusted.
Formula
If the value of the attribute Index_CI_Splits_in_Last_Hour is greater than or equal to 1
Consider increasing the primary allocation for the index component of the file.
Formula
If the value of the attribute Index_Extents_in_Last_Hour is greater than or equal to 1
Consider increasing the primary allocation for the index component of the file.
Formula
If the value of the attribute Index_Extents_in_Last_Hour is greater than or equal to 1
Investigate tasks that can be holding an RLS lock for an excessive a mount of time. The online history component of Tivoli OMEGAMON XE for CICS on z/OS can be used to identify transactions that have been abnormally terminated by CICS because of VSAM timeout conditions (abend code AFCV). If the lock activity is determined to be normal, consider increasing the DTIMOUT value for transactions that use the file, or the FTIMEOUT value defined to CICS.
Formula
If the value of the attribute RLS_Timeouts_in_Last_Hour is greater than 1 and the value of the attribute RLS_Timeouts_in_Last_Hour is less than or equal to 20
Investigate tasks that can be holding an RLS lock for an excessive a mount of time. The online history component of Tivoli OMEGAMON XE for CICS on z/OS can be used to identify transactions that have been abnormally terminated by CICS because of VSAM timeout conditions (abend code AFCV). If the lock activity is determined to be normal, consider increasing the DTIMOUT value for transactions that use the file, or the FTIMEOUT value defined to CICS.
Formula
If the value of the attribute RLS_Timeouts_in_Last_Hour is greater than 20
See also the CICSplex VSAM Analysis attribute group.