A fix is available
APAR status
Closed as new function.
Error description
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: Customers at HBB7730 and up, running with * * large amounts of real storage, generally * * between 256G to 1TB, or with a large * * LFAREA, such as 256G. A PTF will be * * provided at HBB7790 only. * **************************************************************** * PROBLEM DESCRIPTION: This APAR provides new function to * * address scalability issues for * * customers running with large amounts * * of real storage, generally between * * 256G to 1TB, or with a large LFAREA, * * such as 256G. * * * **************************************************************** * RECOMMENDATION: * **************************************************************** This APAR provides new function to address scalability issues for customers running with large amounts of real storage, generally between 256G to 1TB, or with a large LFAREA, such as 256G. Without this APAR applied, the following issues may occur with large amounts of memory or with a large LFAREA: 1. During system initialization, RSM must obtain disabled spin locks to initialize control structures. Running disabled can lead to spin loop time-outs and result in an ABEND071 which can lead to system failure. 2. A large LFAREA (e.g., greater than 256G) requires a large amount of preferred real storage for PFTEs to represent the frames for the LFAREA. During system initialization, obtaining these control structures may deplete preferred storage below the bar. One possible outcome is an XCF WAIT0A2. 3. As the LFAREA size is increased, the amount of preferred storage above the bar is decreased. A lack of preferred storage can lead to a system hang or slowdown as requesters for this storage are indefinitely suspended. 4. Processing requests for 4K frames from the LFAREA can lead to ABEND071 spin loop time-outs. 5. A spin loop time-out ABEND071 may occur when a CONFIG STOR, OFFLINE command is processed for a large amount of real storage or with a large storage increment size, such as 1G or greater. 6. A spin loop time-out ABEND071 may occur while scanning PFTEs during frame steal processing.
Problem conclusion
Temporary fix
Comments
This APAR provides new function to address RSM scalability issues with large amounts of real storage. The following describes the new function provided by this APAR: 1. In the area of RSM initialization, the processing time while running disabled is reduced by initializing frames more efficiently. 2. The area of real storage used to contain the PFTEs for the LFAREA is moved to a new area to help prevent the depletion of preferred storage below the bar. 3. The size of the Pageable Large Area (PLAREA) is reduced to allow more preferred storage above the bar when the LFAREA is very large, generally above 70%. Also, RSM frame steal processing is enhanced to scan the PLAREA for 4K frames to steal. 4. New structures are defined for managing the LFAREA frames that are more efficient and will reduce the amount of time that RSM must run disabled to manage LFAREA frames. 5. Processing for the CONFIG STOR, OFFLINE command has been enhanced to be more efficient to avoid a spin loop time-out ABEND071. 6. RSM frame steal processing is enhanced to be more efficient in scanning the PFTEs by skipping over certain areas that are not eligible for steal processing. The following publications have been updated: z/OS MVS Initialization and Tuning Guide Document Number: SA23-1379 Documentation updates for this publication are located in a pdf file, OA44207.pdf, available at: - http://publibz.boulder.ibm.com/zoslib/pdf/OA44207.pdf z/OS MVS Data Areas Volume 5 Document Number: GA32-0939 A new bit in the RCE is defined to indicate that this function is applied on this system. - In the section titled: RCE Cross Reference Name Hex Offset Hex Value | RCEOA44207APPLIED 14F 80 - In the section titled: RCE Map Dec Hex Type/Value Len Name (Dim) Description 335 (14F) CHARACTER 1 RCEFLAGS4 FLAGS | 1... .... RCEOA44207APPLIED | Indicates APAR OA44207 | is applied on this system ×**** AE15/03/17 FIX IN ERROR. SEE APAR OA47316 FOR DESCRIPTION ×**** PE15/06/03 FIX IN ERROR. SEE APAR OA48001 FOR DESCRIPTION
APAR Information
APAR number
OA44207
Reported component name
RSM - REAL STOR
Reported component ID
5752SC1CR
Reported release
790
Status
CLOSED UR1
PE
NoPE
HIPER
NoHIPER
Special Attention
YesSpecatt / New Function / Xsystem
Submitted date
2014-01-08
Closed date
2014-07-25
Last modified date
2015-07-16
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
OA44858 UA74198
Modules/Macros
IARMN IARRCE IAXBR IAXGA IAXGT IAXMH IAXMI IAXMP IAXMR IAXMT IAXM8 IAXM9 IAXQX IAXRC IAXRG IAXRN IAXSA IAXSB IAXSI IAXUA IAXUC IAXUM IAXUN IAXUO IAXUZ IAXVD IAXVH IAXVS IAXV2 IAXWB IAXXG IAXXI IAXXR IAXYG IAXYZ IAXZVHVH IAXZVPFT IAXZVRIT IAXZXGCB
GA320939XX | SA231379XX |
Fix information
Fixed component name
RSM - REAL STOR
Fixed component ID
5752SC1CR
Applicable component levels
R790 PSY UA74198
UP14/07/30 P F407
Fix is available
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Document Information
Modified date:
16 July 2015