ims logger enhancements - ims ug october 2017 dallas
TRANSCRIPT
Recent changes to help your IMS system run faster and
consume fewer resources
Adam Johanson
IMS Development
October 4, 2017
IMS Logger Enhancements
© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
Important Disclaimer
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© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
V12: Above-the-bar Storage for Log Buffers Introduced
ECSA savings
Specify BUFSTOR=64 on OLDSDEF
Block size must be multiple of 4K
OLDS must be extended format
Extended format OLDS allow for data set striping
Maintenance for Red Alert
–V13: PI71701; V14:PI71702; V15: in base code
V15: Apply PTF for PI86668 (to close soon)
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© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
Log Buffers Above-the-Bar
Calculating ECSA Savings
–Buffer size * number of buffers
Number of buffers: BUFNO on OLDSDEF
Buffer size:
- BLKSZ on OLDSDEF card –or-
physical block size of the OLDS
Logger Exit (DFSFLGX0) and RSR Log Filter Exit
(DFSFTFX0) get address of log buffer
–Supplied exit DFSFTFX0 correctly handles 8-byte
address
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© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
Data Set Striping for OLDS
Data set spread across multiple volumes
–Allows for concurrent I/Os
–OLDS for multiple blocks happen in parallel
Specifying extended format
–Data set type of “EXT”
–DATACLAS and STORCLAS attributes from DASD
personnel
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V15 Logger Enhancements
© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
AS-IS Scenario: IMS Logging from 30,000 ft.
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(Flat file)
© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
As-is: Purpose of the WADS
Performance
To write “small” chunks of data from a log buffer that has not yet been
written to the OLDS
Lets the user of the Logger resume processing quickly, knowing that
their data has been hardened
The WADS is a simple, small, sequential flat file
For performance, the IMS Logger currently builds its own channel
program to write data to the WADS
Exploiting new I/O features requires a change in the current design of
the WADS interface.8
© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
V15: Use of DFSMS Media Manager for the WADS
Media Manager (MM) is a no-charge feature
IMS can now leverage zHyperWrite to reduce replication
latency
–zHyperWrite uses control unit mirroring to write to primary
and secondary devices in parallel
When available, IMS can also use zHPF for writing to the
WADS
–System z High Performance FICON
–Simply quicker I/O, not environment-specific
Positions Logger to easily exploit new hardware features9
© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
To-Be Scenario:
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(VSAM LDS)
© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
V15 Logger MM - Externals
The WADS will now be a VSAM Linear Data Set– Sample JCL provided
There is a parameter to enable/disable IMS’ use of zHyperWrite– <LOGGER> section of DFSDFxxx
ZHYPERWRITE=(WADS=YES)
– To MVS, zHyperWrite is enabled/disabled at LPAR level SYS1.PARMLIB(IECIOSxx) SETIOS HYPERWRITE=YES/NO
D IOS,HYPERWRITE
– zHPF used if it’s enabled D IOS,ZHPF
– BSAM started using zHPF for OLDS writes in z/OS 1.13 if zHPF is enabled
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© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
V15 Logger Media Manager
Software requirements - zHyperWrite– Primary and secondary volumes must be in Metro Mirror
relationship in full duplex status
– Must be managed by HyperSwap
Software requirements - zHPF– Simply used if available on LPAR
Value of zHyperWrite parm added to /DIS OLDS output– APAR PI82325
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© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
V15: zHyperWrite for the OLDS
Support added by APAR PI75575– Requires DFSMS APAR OA51385– Only a pre-req in terms of functionality– Not an SMP/E pre-req
OLDS must be defined as extended format– Already extended format if using BUFSTOR=64
Enable via:– ZHYPERWRITE=(OLDS=YES) in <LOGGER> section of
DFSDFxxx
– If enabled, but pre-reqs not met (OA51385, extended format, etc.), nothing bad happens Just not using zHyperWrite
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© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
Encryption from 50,000 feet:
Data sets defined with a key label– Part of data set’s MVS catalog entry
Key label passed to ICSF to obtain “wrapped” key– ICSF – Integrated Cryptographic Services Facility– Maintains “wrapped” keys in CKDS
Cryptographic Key Data Set
– Wrapped key is a key that’s encrypted under the “master” key
Master key located in the Cryptographic Express (CEX) card
Wrapped key un-encrypted via master key within CEX card
Key never exists as plaintext in any address space, only the CEX card
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© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
V15: WADS Encryption
To enable:– DFSMS APAR OA50569
APAR is for all access methods encryption
– Support added via PI84947
– Note: not enabled via an explicit parameter
– WADS must be: Defined as extended format Defined with a key label
After applying PI84947, migration to encrypted WADS can be done while IMS remains up– Procedure to be published in System Admin guide
– Involves using ‘extra’ WADS not currently in use by IMS
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© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
Encryption Set-up
Ability to read encrypted WADS: access to key label
DASD volume-level utilities don’t require this access
Doc pointed to by OA50569:– http://publibz.boulder.ibm.com/zoslib/pdf/OA50569.pdf– Chapter 2: set-up
Keys created in CKDS for use by ICSF
New profile in FACILITY CLASS– STGADMIN.SMS.ALLOWDATASET.ENCRYPT
Access to key label via CSFKEYS class
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© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
Enabling Encryption for OLDS/SLDS
Any supported release of IMS!
https://www.ibm.com/support/knowledgecenter/SSEPH2_15.1.0/com.ibm.ims15.doc.sag/system_admin
/ims_dataset_encryption.htm
https://www.ibm.com/support/knowledgecenter/SSEPH2_14.1.0/com.ibm.ims14.doc.sag/system_admin
/ims_dataset_encryption.htm
https://www.ibm.com/support/knowledgecenter/SSEPH2_13.1.0/com.ibm.ims13.doc.sag/system_admin
/ims_dataset_encryption.htm
Requires OA50569
OLDS:
– Can do while IMS remains up via ‘extra’ OLDS and commands:
/STO OLDS x
/STA OLDS x
SLDS
– Change skeletal JCL member to specify DSKEYLBL for SLDS/RLDS
– Or specify a DATACLAS with an associated key label
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Logger Setup Recommendations
© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
Dual Logging
Dual OLDS– OLDSDEF MODE=DUAL in <LOGGER> section of DFSDFxxx
Dual WADS– WADSDEF MODE=DUAL
Redundancy of data
Different packs for OLDS and WADS– Don’t want to lose both simultaneously– Multiple OLDS can be on same pack, within reason
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© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
Buffer Size
Specified by BLKSIZE on OLDSDEF -or-
– Physical block size of OLDS
Sizes 6K – 30K– Multiple of 2K for 31-bit buffers– Multiple of 4K for 64-bit buffers
Live in common storage– ECSA if using BUFSTOR=31 (default)
Tradeoffs:– Smaller buffer sizes make IOS busier– Larger buffer sizes take longer to fill and write out– Desire little-to-no wasted space on track
– 24K: good compromise and 2 buffers fit on track20
© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
Number of OLDS
IMS has maximum of 100 (numbered 0-99)
When all OLDS are awaiting archive, IMS hangs
Not looking for “exact” number, just a comfort level
Goal:
– Easily handle high-volume period
– Not have so many that more can’t be added when needed
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© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
Size of the OLDS
Largely dependent on frequency of switches
– IEBEYEBALL messages DFS3257I during high-volume
Efficient use of DASD
– Little-to-no empty space on pack
– Example: A model-3 3390 pack contains 3,339 cylinders
OLDS of 1,000 cylinders wastes 339 cylinders on pack
OLDS can be 1,113 cylinders for 3 OLDS/pack
OLDS can be 1,669 cylinders for 2 OLDS/pack
Size all of them the same
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© 2017 IBM CorporationDallas / Ft. Worth RUG, October 2017 – Logger Enhancements
Recommendations for Archive
Own scheduling class in JES
– No contention for initiators
Unique job names
– In GENJCL, job name can include timestamp
Symbolic keyword %ARTIME Granular to tenth of a second
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Questions?