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Abstract
An enhancement has been made available in IBM i 6.1 and later releases, which may help with integrated file system SAV performance.
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You are in: IBM i Technology Updates > General IBM i Operating System > Achieve faster IFS save times using SAV with ASYNCBRING
ASYNCBRING will enable objects to be asynchronously brought into memory early so they will not need to be paged in when first accessed by the SAV processing. While results will vary, testing in the lab and by a few customers have shown some dramatic improvements - up to 60% faster save times in some cases. The performance gain seen is dependent on the directory structure, number and size of objects saved, amount of memory available, and the system configuration. This enhancement is available on both the SAV command and QsrSave() API.
From the PTF cover letter:
A new parameter will be added to the SAV command and a new key added to the QsrSave API which will specify whether objects should be asynchronously brought into memory during the save processing.
Asynchronous brings will only be done when saving objects from the root ('/'), QOpenSys, and user-defined file systems.
SAV command help text for ASYNCBRING:
Asynchronous bring. Specify whether objects should be asynchronously brought into memory during the save processing.
Depending on the directory tree structure, the amount of memory available, and the number of objects which qualify for the save, asynchronously bringing the objects may improve save performance. The best performance improvement may be seen with a well balanced directory tree in which all objects qualify for the save. In situations where a large number of objects reside in a single directory, few objects qualify for the save, or the system is memory constrained, performance may degrade with ASYNCBRING(*YES) specified. The default is *NO.
The possible ASYNCBRING parameter values are:
- *NO - Asynchronous bring is not done
- *YES - Asynchronous brings are done
V7R1 PTF information:
SI44688 - Save/Restore PTF with new function added
SI45792 - Supersedes SI44688 and contains additional SAV performance improvements
SI44710 - BRMS PTF that supports ASYNCBRING
See IBM support page ASYNCBRING enablement for more information.
Save Object (QsrSave) API documentation:
Valid Keys
The following table lists the valid keys for the key field area
of the variable length record. For detailed descriptions of the
keys, see the Field Descriptions.
Some messages for this API refer to parameters and values of the
Save Object (SAV) command. This table can also be used to locate
the key names that correspond to the SAV command parameters. The
field descriptions contain, in addition to detailed
descriptions, the corresponding parameter values.
The object path name key and the device path name key are
required keys. The other keys are optional.
Key Type Field SAV Command Parameter
1 CHAR(*) Device path name DEV
2 CHAR(*) Object path name OBJ
3 CHAR(1) Directory subtree SUBTREE
4 CHAR(1) System SYSTEM
5 CHAR(40) Change period CHGPERIOD
6 CHAR(1) Object precheck PRECHK
7 CHAR(10) Target release TGTRLS
8 CHAR(*) Update history UPDHST
9 CHAR(*) Volume identifier VOL
10 CHAR(*) Label LABEL
11 BINARY(4) Sequence number SEQNBR
12 CHAR(7) Expiration date EXPDATE
13 CHAR(1) End of media option ENDOPT
14 CHAR(1) Clear CLEAR
15 CHAR(1) Data compression DTACPR
16 CHAR(1) Data compaction COMPACT
17 CHAR(*) Optical file OPTFILE
18 CHAR(1) Save while active SAVACT
19 CHAR(*) Save-while-active message queue SAVACTMSGQ
20 CHAR(*) Output OUTPUT, INFTYPE
21 CHAR(1) Use optimum block size USEOPTBLK
22 CHAR(1) Save-while-active option SAVACTOPT
23 CHAR(10) ASP device name ASPDEV
24 CHAR(*) Name pattern PATTERN
25 CHAR(2) Scan objects SCAN
26 CHAR(10) Synchronization ID SYNCID
27 CHAR(1) Private authorities PVTAUT
>> 28 CHAR(1) Asynchronous bring ASYNCBRING <<
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Document Information
Modified date:
10 January 2020
UID
ibm11127931