A fix is available
APAR status
Closed as new function.
Error description
New Function
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: * * DFSMShsm V2R3 and higher users who use * * automatic migration to Cloud. * * * **************************************************************** * PROBLEM DESCRIPTION: * * New Function. * * TCT: Improve Performance * * * * Keywords: * * DFSMSCS/K * **************************************************************** * RECOMMENDATION: * **************************************************************** New Function. Increase the maximum number of large data sets that can migrate to the cloud concurrently from two to the maximum number of CEC threads minus one.
Problem conclusion
DFSMShsm has been enhanced to increase the maximum number of large data sets that can migrate to the cloud concurrently from two to the maximum number of CEC threads minus one. The following publications updates are being made for this APAR: z/OS DFSMShsm Data Areas SRL: GC14-7504-xx The following updates were made: Chapter 43. MCVT-Management Communication Vector Table Table 111. MCVT-Management Communication Vector Table (continue) Offsets Dec (Hex) Type Length Name Description 591 (24F) BITSTRING 1 * Flags. ...1 .... MCVTF_CLOUD_TRACE ON-Threads checking and reservation traces will be issued. .... xxxx * Reserved 974 (3CE) FIXED 2 MCVT_Small_DS_Number Number of small data sets during cloud migration. 1452 (5AC) FIXED 4 MCVT_LARGE_DS_SIZE The size of a large DS in tracks 1456 (5B0) FIXED 4 *(4) Reserved. MCVT Data Area Cross-Reference Table 113. MCVT Data Area Cross-Reference Table (continue) Hex Hex Struct Name Offset Value Level MCVTF_CLOUD_TRACE 591 10 4 MCVT_LARGE_DS_SIZE 5AC 2 MCVT_Small_DS_Number 3CE 2 Chapter 45. MGCB-Migration Global Control Block Table 116. MGCB-Migration Global Control Block (continue) Offsets Dec (Hex) Type Length Name Description 275 (113) ..1. .... MGCF_MI_SG_AUTO ON - MIGRATE SG command is processed as Automigration ...x xxxx Reserved 358 (166) FIXED 2 MGCB_SSL_WAIT Interval in seconds before the next SSL processing Table 117. MGCB Data Area Cross-Reference Table (continued) Hex Hex Struct Name Offset Value Level MGCF_MI_SG_AUTO 113 20 4 MGCB_SSL_WAIT 166 3 z/OS DFSMShsm Implementation and Customization Guide SRL: SC23-6869-xx Chapter 17. Tuning DFSMShsm Tuning patches supported by DFSMShsm 1. Set the wait time before the large data set processing restarts when migrating to cloud (changed) A limited number of large data sets can be migrated to the cloud at the same time. If this number is exceeded, large data sets will be skipped. These large data sets will be revisited later when the currently processing large data sets have complete. When only the large data sets remain to process, DFHSMShsm will wait this interval before the next scan. The following PATCH can be used to change this interval. PATCH .MGCB.+152 X'nnnn' Where nnnn - the time in seconds. The default value is X'001E' (30 seconds). 2. Set the interval for issuing the Disk Controller busy, ARC1587I, message (changed) An interval of time exists between the issuing of an ARC1587I message if all disk controller cloud data movement threads are busy. The following PATCH can be used to change the interval in which the message is issued: PATCH .MGCB.+164 X'nnnn' Where nnnn - the time in seconds. If this value is set to X'7FFF', no interval checking will be executed and no ARC1587 messages will be issued. The default value is X'7FFF'. 3. Setting the maximum wait time in seconds to get a disk controller for moving data to the cloud (changed) You can set the maximum wait time in seconds to get a disk controller cloud data movement thread lock. Space Management for a volume will terminate, if a disk controller cannot be reserved within the allotted time. When the wait time is exceeded, message ARC0535I is issued and volume processing is terminated. The following patch can be used to tune the wait time: PATCH .MGCB.+9A X'nnnn' Where nnnn is the time in seconds. If this value is set to X'7FFF', no interval checking will be executed and Space Management for a volume will not be terminated. The default value is X'7FFF'. 4. Setting the minimum size of a large data set The data set will be considered as "large", if its size is larger than this value. The following patch can be used to tune this value: PATCH .MCVT.+5AC X'nnnnnnnn' Where nnnnnnnn is a data set size in tracks. The default value is X'000186A0' (100000) tracks. 5. Setting the minimum number of small data set threads when moving data to the cloud. Since there is a limited number of CEC threads for data movement, DFSMShsm prevents large data sets from consuming all threads and preventing any small data sets from being processed. As a default, DFSMShsm reserves one thread out of the maximum number of threads in a CEC to process small data sets. If it is known that only large data sets that exceed the default of 100000 tracks, or an updated value patched in .MCVT.+5AC, then this value should be patched to '0'. This enables DFSMShsm to utilize all CEC threads for processing large data sets without concern for blocking out small data set processing. The following patch can be used to tune this value: PATCH .MCVT.+3CE X'nnnn' Where nnnn is a number of small data sets. The default value is X'0001'. 6. Allowing DFSMShsm to trace threads checking and reservation during migration to cloud storage. By default, threads checking and reservation traces will not be written during migration to cloud storage. To enable this option, the following patch should be applied: PATCH .MCVT.+24F BITS(...1....) This processing can be reversed or disabled by issuing the following patch: PATCH .MCVT.+24F BITS(...0....) 7. Defining MIGRATE STORAGEGROUP command behavior MIGRATE STORAGEGROUP command migrates the eligible data sets on the volumes in one or more storage groups. When the MIGRATE STORAGEGROUP command is issued, DFSMShsm will read the SMS storage group definition and determine the list of volumes defined by this storage group. Then the data sets residing on these volumes will be processed in a similar way to automatic migration processing. By default the main differences are: 1. Volumes can be processed several times a day. 2. In a multihost environment, the command can go into a wait state up to 5 minutes if the volume required for processing is reserved by another host. The following patch can be applied to provide MIGRATE STORAGEGROUP command behavior that is fully consistent with automatic migration: PATCH .MGCB.+113 BITS(..1.....) This processing can be reversed or disabled by issuing the following patch: PATCH .MGCB.+113 BITS(..0.....) 8. Allowing DFSMShsm automatic functions or MIGRATE STORAGEGROUP command to process volumes other than once per day (changed) Running MIGRATE STORAGEGROUP command multiple times a day If MIGRATE STORAGEGROUP command behavior is fully consistent with automatic migration (by the patch applied) and DAYS(0) or MOVE parameter is not specified, the volumes can be processed only once every 14 hours. In this case the tuning of MIGRATE STORAGEGROUP command processing is the same as automatic primary space management of SMS volumes. MIGRATE STORAGEGROUP command with DAYS(0) or MOVE parameter can process the volumes once every 3 hours and 59 minutes. If MIGRATE STORAGEGROUP command with DAYS(0) or MOVE parameter has run to completion and you want to start this command again, use the following patch: PATCH .MCVT.+5B0 X'nnnnnnnn' Minimum time between MIGRATE SG() command with DAYS(0) or MOVE parameter (Binary number in seconds) Example of redefining an interval for MIGRATE STORAGEGROUP command with DAYS(0) or MOVE parameter of SMS volumes processing There are times when a user may want to modify the definition of a minimum time between volume processing to occur more often or less often. By changing the bytes that define the minimum amount of time between volume processing, you can permit MIGRATE STORAGEGROUP command with DAYS(0) or MOVE parameter to be performed at a different frequency. For example, a user may want a volume to be processed more frequently than 3 hours and 59 minutes. In order to determine the minimum interval of 30 minutes, you must apply the following patch: PATCH .MCVT.+5B0 X'00000708' VER(.MCVT.+5B0 X'00003804') 9. Setting the wait Interval before the next SSL checking will be executed during migration to cloud storage when multiple migration subtasks are enabled. The following patch can be used to change the interval in seconds before the next migration subtask will start to migrate the first data set to cloud storage. PATCH .MGCB.+166 X'nnnn' Where nnnn - the time in seconds. If this value is set to X'0000', the next migration subtask will not wait before data set processing. The default value is X'0000' Example: PATCH .MGCB.+166 X'003C' Subtask1 starts immediately, Subtask2 starts 60 seconds after the first, Subtask3 starts 120 seconds after the first, Subtask4 starts 180 seconds after the first, etc. KEYWORDS: DFSMSCS/K
Temporary fix
Comments
APAR Information
APAR number
OA58915
Reported component name
DFSMSHSM, ISMF
Reported component ID
5695DF170
Reported release
220
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2020-01-11
Closed date
2020-10-13
Last modified date
2020-11-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UJ04180 UJ04181
Modules/Macros
ARCMSTAI ARCMMQ ARCMGDI ARCCMHRD ARCMXSB ARCCBS ARCMXMGR ARCSMPMQ ARCMVOL ARCSELAV ARCMXCB ARCGCPU ARCMGCB ARCMCK ARCCVT ARCMTCB ARCMDQE
| SC236869xx | GC147504xx |
Fix information
Fixed component name
DFSMSHSM, ISMF
Fixed component ID
5695DF170
Applicable component levels
Fix is available
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[{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG19M","label":"APARs - z\/OS environment"},"Platform":[{"code":"PF054","label":"z\/OS"}],"Version":"220"}]
Document Information
Modified date:
03 November 2020