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Storing and Managing Data in Today’s z/OS Environment

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Presentation on theme: "Storing and Managing Data in Today’s z/OS Environment"— Presentation transcript:

1 Storing and Managing Data in Today’s z/OS Environment
Michael E. Friske

2 Storage Challenges Compounded growth Cost reduction pressure
Changing regulatory and business requirements Higher availability requirements Data life cycle management

3 Hardware Solutions That Can Help Address These Challenges
Storage Tiering IBM DS8870 with EasyTier EMC VMAX with FAST HDS VSP with HDS Dynamic Tiering Virtual Tape IBM DS7700 Oracle VSM EMC DLm CA-Vtape (software/hardware)

4 Traditional Storage Hierarchy
High Performance Cache or SSD Enterprise Disk ML1 Disk ML2 Tape Low Cost

5 Data Life Cycle Active data Less active data Inactive data
Stored on primary disk Less active data Migrate to ML1 disk Uses MIP’s Must be recalled to use Inactive data Migrate to ML2 tape Must recall to use Primary Disk ML1 Disk ML2 Tape

6 SMS MGMTCLAS Number of days on primary disk
Number of days on ML1 volumes When to expire Management criteria Number of days since the create date Number of days since the last reference date

7 Disk Options Flash Drives (100GB, 200GB, 400GB, 1.6TB, and 3.2TB)
Solid State Drives (400GB) SAS Drives 10,000 RPM (300GB, 600GB, 900GB, and 1.2TB 15,000 RPM (146GB and 300GB) Nearline SAS Drives 7,200 RPM (1TB, 2TB, 3TB, and 4TB)

8 Determining What Data Went on Which Drives
Disk subsystems with a mix of different types of disk drives Analyze RMF and/or SMF reports Map SMS storage groups to specific disk drives Monitor for changes in access patterns A homogenous disk subsystem that works for all types of data

9 Hardware Based Tier Management
IBM DS8870 EMC VMAX HDS VSP Easy Tier Fully Automated Storage Tiering (FAST) HDS Dynamic Tiering

10 First Generation Tiering
The Disk subsystem monitored the I/O activity for each extent Extents were dynamically relocated to different tiers based on internal algorithms

11 Shortcomings of First Generation Tiering
Data is moved at the extent level, not on a data set boundary Data sets move around due to reorgs, defrags, copying, etc. Patterns of access change based on the time of day or the day of the week Data is placed on a storage tier based on access, not SLA’s

12 Addressing the Shortcomings
Hints from the host z/OS 2.1 Class Transitions Hitachi Tiered Storage Manager

13 MGMTCLAS - Expiration

14 MGMTCLAS - Migration

15 MGMTCLAS – Class Transition

16 MGMTCLAS – Transition Technique

17 Easy Tier with Class Transition
Enterprise $ Class transition after 120 days Nearline ½ $ Recall Migrate after 366 days

18 Transition Copy Technique

19 Serialization Error Exit
DB2 - Invoke DB2 to close and unallocate the object. If this is successful, the object is serialized and moved and DB2 is invoked to reopen the object. CICS - Invoke CICS to take the object offline. If this is successful, the object is serialized and moved and CICS is invoked to reopen the object. ZFS - Invoke zFS to unmount the data set. If this is successful, the data set is serialized and moved and zFS is invoked to remount the data set. EXIT - Enables users / ISVs to provide an exit that will be invoked before and after transitioning an allocated data set. The data set is only transitioned if serialization is obtained after the first invocation of the exit. NONE

20 Transition Invokes the ACS Routines
Once DFSMShsm determines that a data set has met the Class Transition criteria specified by the Management Class, it invokes the ACS routines to determine what the transition should be ACS Routines are invoked with new ACS environment (&ACSENVIR) of SPMGCLTR, for 'space management class transition' The following routines are invoked (in this order) Storage Class Management Class Storage Group Any or all can be transitioned If the classes and storage group returned match the existing classes and storage group, then no transition occurs




24 Example – New Data Set Flash Enterprise Nearline Initial access
Random reads & writes with periods of high access STORGRP = TIER0 Flash Enterprise MGMTCLAS No migration Transition after 60 days Flash Enterprise TIER0 Nearline TIER1

25 Example – Access Drops Off
Access after 3 months Accessed less No write activity STORGRP = TIER1 Enterprise Nearline MGMTCLAS Migrate after 30 days of inactivity Expire after 7 years Transition after 60 days Flash Enterprise TIER0 Nearline TIER1

26 Example - Inactive Flash Enterprise Virtual Tape Nearline TIER0 TIER1
Recall Nearline Migrate TIER1

27 Cost Savings Reduce CPU costs by eliminating ML1
No need to compress or decompress data Eliminate recalls from ML1 Reduce CPU costs with Class Transition May be able to use FlashCopy May be able to wait longer before migrating to ML2 Reduce the purchase price for new disk subsystems

28 Virtual Tape Subsystems
IBM TS7720 EMC DLm Oracle VSM

29 Cost Reduction with Virtual Tape
Reduces floor space requirements Reduces the need for tape handlers Replicate tape data to remote site for disaster recovery Batch cycle runs faster Tapeless tape subsystems Eliminate the need to tape handlers No need to buy physical tape media

30 zEnterprise Data Compression
zEDC Express is an IO adapter that does high performance industry standard compression Used by z/OS Operating System components, IBM Middleware, and ISV product Required z/OS 2.1 and EC12 or BC12

31 SMS Compression with zEDC
Can be used in place of generic or tailored compression for QSAM and BSAM data sets CPU savings for existing users of SMS compression Disk savings for users who are not currently using SMS compression

32 Other Features That Can Reduce HSM CPU Consuption
Use RLS to access the HSM CDS’s Replace Interval Migration with On-Demand Migration Take advantage of Multiple Address Space HSM (MASH) support Implement the Common Recall Queue Implement Fast Subsequent Migration Avoid reorganizing the HSM CDS’s too frequently HOLD LOG if log data is not required

33 RLS for HSM CDS’s Reduces CPU overhead for HSM due to less calls to GRS, less buffer invalidation, and less I/O to disk Reduces elapse times for long running tasks like Primary Space Management, Secondary Space Management, EXPIREBV, Recycle, and Audit

34 HSM On-Demand Migration
Does not check every volume each hour to see if the volume is over the high threshold Eliminates the spike in CPU usage for HSM at the top of each hour Will only process a volume once after it goes over the high threshold

35 HSM MASH Can be used to run HSM backup and space management functions at a lower priority (different WLM Velocity Goals) Can be used to spread tasks out to more address spaces and to reduce SYSZTIOT contention

36 HSM Common Recall Queue
Allows multiple hosts to process recalls Can be used to limit tape processing on certain CPU’s Helps with workload balancing Multiple recalls for different data sets on the same tape from different CPU’s can be processed on a single CPU Allows higher priority requests across the sysplex to get process first over lower priority requests Keeps recall requests if HSM is shut down or goes down unexpectantly

37 Fast Subsequent Migration
Saves CPU costs associated with re-migrating data sets that were recalled but not updated Reduces the need to run RECYCLE

38 HSM CDS Reduction Turn on CA Reclaim for the HSM CDS’s
Do not reorganize the HSM CDS’s just because they have CI and CA splits Only reorganize the HSM CDS’s to reclaim space

39 Other Cost Avoidance Measures
Clean up the errors HSM finds each night Analyze MGMTCLAS definitions periodically, and adjust them if necessary Check for data sets in the wrong MGMTCLAS

40 Data That Can Be Used for Analysis
HSM Logs HSM FSR records DCOLLECT data

41 Questions ?

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