SMS Volume selection appears to be selecting the wrong volume. Please refer to APAR in the future for changes and additions. This list is intended to enhance the customers analysis of SMS managed data volume selection. Volume selection for system managed data first selects from the list of primary volumes.
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SMS Volume selection appears to be selecting the wrong volume. Please refer to APAR in the future for changes and additions. This list is intended to enhance the customers analysis of SMS managed data volume selection. Volume selection for system managed data first selects from the list of primary volumes. If there are no primary volumes, SMS selects from the secondary volumes.
If there are no secondary volumes available, SMS will select from the tertiary candidates. Secondary volumes are those which do not meet all the specified criteria above. Volumes are marked tertiary if the number of volumes in the storage group are less than the number of requested volumes. All volumes in the storage group are marked tertiary. Volume selection proceeds to first use the primary volume list, followed by the secondary volumes and lastly the tertiary volumes.
A common example of this is when a tape request of 5 volumes will cause a TMM buffer storage group containing 2 volumes to be marked tertiary while a spill Quiesced storage group containing 5 volumes to be marked secondary. The result is that the quiesced volumes is preferred before the TMM volumes. SRM selects volumes based on channel path utilization. Volume was rejected. Volume could not allocate the primary space request without going over threshold. See OW Volume or Storage Group is Quiesced.
Volume did not satisfy the the requested performance MSR. If the requested MSR ex: 15ms is faster than the fastest device in a Storage Group, the requested MSR s are relaxed so that the fastest devices are eligible for the primary volume list. All other requirements Availability, Threshold, Enabled This method prefers volumes which can meet the performance objectives in the Storage Class while at the same time not giving away fast volumes for slower requests.
The result of OW allows the customer to specify no performance preference for SMS volume selection. An Accessibility value of preferred Default specified in the Storage Class will remove all volumes which do not have extended platform support. See OW, OW An Accessibility value of standard specified in the Storage Class will remove all volumes from the primary list which have extended platform support Introduced in DFSMS Reference OW This may result in the MVS device control blocks not reflecting the current state of the volume.
The device s should be varried offline and back online to update the MVS control block status. A volume is considered below high threshold when the primary space allocation does not cause the high threshold limit to be exceeded. The above 4 categories above Threshold, Status are again divided. In which case those volumes which support concurrent copy T0 are preferred over volumes which do not support concurrent copy.
Note: All volumes which are behind a or a controller with extended platform microcode are considered to support concurrent copy T0. This results in volumes which are behind a controller that supports Extended Format to be preferred over volumes which do not have this feature.
This will result in the non Cached devices being over utilized and the Cache active devices will not be selected until all the non-Cached devices are above high threshold.
This A. In this instance all non-Cache active volumes are placed ahead of Cache active volumes. The last division deals with volumes which are identical in the previous checks.
Identical volumes are ordered from the largest amount of free space to the smallest. OW adds randomization to final selection routines. If you can not determine the cause of a specific volume selection problem, Please have the following available before calling support.
Issue the following MVS command. Run the job in question. Take a dump of the SMS address space. An example follows using MVS commands. Setup option 0 defaults. This can be faxed to IBM service for faster response. Problem summary.
What is DFSMS?
A security administrator or the data owner must write access rules to permit other users access. A security administrator must write access rules to permit users to access data on a secured volume. For more information on writing access rules, see Access Rules. CA ACF2 also provides protection for tape data sets at the data-set-name level. However, your site must use a tape management product to use this feature.
DFSMS STORAGE ADMINISTRATION REFERENCE PDF
Fenrijora Note, that the first four commands are only for diagnosis and repair. In an SMS environment, the storage management functions defined in the management class and the storage group control the SMS-managed data sets in place of the parameter or command definitions within DFSMShsm. Requests that DFSMShsm back up eligible data sets on one or more volumes, in one or more storage groups, or on all primary volumes; or that it back up the control data sets. Long-running commands are limited to having only one of each such command being performed by DFSMShsm at any time. Deletes a migrated data set without recalling the data set.