sap r/3 performance review/system health check

sap r/3 performance review/system health check
SAP NetWeaver on IBM i
Recommendations and Review
Version 2.4
September 2015
IBM Systems Technology Group
IBM Corporation
Ron Schmerbauch
Please direct questions or comments to:
Ron Schmerbauch
(507) 253-4880
rschmerb@us.ibm.com
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SAP NetWeaver on IBM i - Recommendations and Review
July 2015
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TABLE OF CONTENTS
I
II
III
IV
V
I
Introduction
Highly Recommended Actions
Further IBM i OS and DB items
Further SAP items
Infrastructure Data
INTRODUCTION
The purpose of this document is to provide guidance regarding SAP environments
running on IBM i. This material represents a collection of review steps based on
SAP/IBM documentation, SAP Notes, IBM Redbooks, and experiences of the IBM i
Development team.
This document is not intended to cover all issues or situations, but should be
helpful to improve SAP on i performance and/or implementation.
The document is relevant across the SAP on IBM i Database and SAP Application
Servers, which can be running on IBM i or Windows. The following releases are
applicable:
 SAP NetWeaver with 6.x or 7.x kernels
 IBM i 6.1 or after
 SAP components dependent on these releases ( e.g. ECC 6.0, BW 7.0)
The commands described in this document will require the appropriate
authorizations in order to execute successfully, such as the appropriate SAP
authorization profile for SAP transactions, and appropriate privileges for IBM i and
Windows commands.
SAP and all SAP product and service names mentioned herein are trademarks or
registered trademarks of SAP AG in Germany and several other countries around
the world.
IBM, IBM i, POWER, Power Systems, DB2, Enterprise Storage Server, TotalStorage
are trademarks or registered trademarks of the International Business Machines
Corporation in the United States and other countries.
Other products may be trademarks or registered trademarks of their respective
companies.
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II
HIGHLY RECOMMENDED ACTIONS
Take the following actions on all SAP on i partitions and systems to make
sure currently recommended default settings for function and performance
are all in place.
1) Go to the SAP on i web page. Locate and follow the link to the Info
Apar for the IBM i release level you have installed. All PTF prerequisite
requirements in the following recommendations are already included in
the info apar lists.
You may also follow the link found there to be notified of future info
apar updates. This will ensure that you are aware of the latest
recommendations as you perform regularly scheduled maintenance.
2) Make sure you have already taken appropriate action for all known
issues with your specific IBM i OS release level as described in SAP
note for that release. Some of these actions require that the SAP
system be down.
 6.1 1148480
 7.1 1432783
 7.2 2011710
3) Check OS level settings as documented in SAP notes 428855 and 49201.
Some settings are dynamic and take effect immediately. Some will take
effect at the next IPL.
Also set IBM i system value QDBFSTCCOL to *ALL – this is a dynamic
setting and can be applied at any time. If resources are available,
QDBFSTCCOL will collect DB statistics that are useful to the optimizer.
If system resources are not available, the task will sleep and not disrupt
operations. This can be done with the CL command CHGSYSVAL
QDBFSTCCOL *ALL.
4) Change the journal settings for each SAP SID if they do not match the
settings given on the CHGJRN statement below. Use WRKJRNA to
display the current attributes. Only change the settings when the SAP
system is down. CHGJRN JRN(R3<sid>DATA/QSQJRN) JRNRCV(*GEN)
RCVSIZOPT(*RMVINTENT *MAXOPT2 *MINFIXLEN) MINENTDTA(*FILE)
JRNOBJLMT(*MAX10M) This statement represents the combined effect
of SAP notes 424866, 448552, 1449715 and 1366799. Specific PTF
levels are required as documented in the notes.
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5) Partitions using SAP Java based applications should move to IBM i 6.1
or later and the SAP JVM. SAP JVM is the only JVM supported by SAP
as of October 2012. See SAP JVM 4 for details and relevant notes.
6) Review SAP transaction ST02 in each SAP ABAP instance. Hit ratios
should be high and swaps should be low. Poor ST02 settings can cause
performance issues on any HW, OS, DB configuration. The following
SAP notes may be applicable depending on your release level and
which buffers are swapping : 16244, 670505, 1267828, 649613.
Changes to SAP buffer settings take effect at an SAP instance restart.
7) A performance benefit from reduced CPU consumption may be realized
with kernel release 7.20 and after, especially on systems with larger
numbers of processors. This is achieved by changing the ES/TABLE
instance profile parameter related to shared memory handling as
described in SAP note 808607. Certain pre-requisites must be met. IBM
i 7.1 PTF group SF99707 level 4 or later is recommended when using
this setting.
8) SAP kernel release 7.4x requires changes that were not necessary at
7.2x releases. SAP note 2098347 summarizes necessary actions.
III
FURTHER IBM I OS AND DB ITEMS
The following checks and recommendations may be of benefit within the OS
and database.
1) For improved performance with IO intensive workloads (batch, BW or
other complex queries), move to IBM i release 7.2 to take advantage of
DB2 data access optimizations included within that release level.
2) If you often update table structures in transports, it can be difficult to
obtain the exclusive lock required to run the SQL ALTER TABLE
statement on a running system. SAP note 1952271 provides directions
on how to enable a new option on IBM i 7.1 and later that will make it far
more likely that the necessary lock will be obtained.
3) If multiple SAP systems on a partition are using the /Qfilesvr.400
directory to access the same server in parallel, they may see a benefit
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by allowing multiple connections from the client to the server. On the
client lpar, install IBM i 7.2 and add a system wide environment variable
QIBM_RFS_CONNECTION_POLICY, setting the value to ‘1’. Existing
directories in Qfilesvr.400 need to be recreated and jobs using that
directory restarted before the value will take effect. See the IBM
Knowledge Center for details.
4) Periodically check for any severe HW or OS issues in each IBM i
partition with the CL commands DSPMSG QSYSOPR and WRKPRB.
5) Use IBM i CL command WRKDSKSTS. Check for unbalanced capacity or
individual disk units that have far higher utilization rates than all others
over a sustained period of time. Remedy with STRASPBAL, either with
the *CAPACITY option or after running TRCASPBAL to collect information.
It may be helpful to periodically use STRDSKRGZ to consolidate disk
space when you have reached a high disk capacity within an ASP.
6) If you are using a separate ASP just for journal receivers in library
R3<sid>JRN, note that the current defaults are to include this library in
the same ASP as the R3<SID>DATA library. The former
recommendation was to have a second ASP, but as disk capacities have
increased, fewer units were required in the ASP, leading to possible
situations where the work is not spread across enough disk units.
Consider moving R3<SID>JRN back to the ASP where the
R3<SID>DATA is located.
7) Prior to IBM i release 7.1, the default size of a journal receiver is
connected to how many disk units it is automatically spread across by
the IBM i OS. The default size spreads each receiver across 10 units if
there are that many in the ASP where the receiver resides. Increasing
the receiver size can spread the load over more disk units and can
reduce the number of receiver objects to manage during save
operations. The receiver size can be increased with the IBM iNavigator
(formerly IBM i Access Operations Navigator) by selecting Database,
then Schema, then Journal objects, then Properties panel and changing
the THRESHOLD value.
For release 7.1 and after, the receivers are spread across all disk units
in the ASP.
8) To automatically monitor detachment of Journal receivers so they can
be saved and deleted, see SAP note 82079.
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9) Periodically (quarterly or yearly) use SAP transaction DB02 to identify
files that might be reorganized. Reorganization is not generally
required, but may be useful after significant archiving; client deletes
when no client will be replacing the old one; or before SAP release
upgrades. See SAP note 84081. Sizes of deleted data reported by
DB02 can be overestimated because the calculations are based on the
maximum row length size instead of on the actual size (variable length
field may not be using the maximum length). To check actual sizes, use
the IBM i Access Navigator to connect to your DB server partition.
Choose Databases, then Schemas. You may have to add your SAP
library name to the schema list. Display the “Description” of any file
you might want to reorganize to see the actual size and how much of the
file size is varying length data. A high percentage of varying length
data indicates that an offline reorganization would be more effective at
reclaiming space. If there is no or very little varying length data, online
reorganization may be as effective as an offline reorganization.
Reorganization can be run from the System i Navigator or from the IBM i
command line, but note that only the Navigator can show you status
messages regarding the progress being made toward completion of the
operation.
For offline reorganization from the Navigator, choose the table, then
Data->Reorganize. On the popup select “By Selected Index” and
“Table Key”, do not select “Allow reorganization to be suspended”. If
you do offline reorganization from the command line, use the command
RGZPFM FILE(R3<sid>DATA/<file>) KEYFILE(*FILE) ALWCANCEL(*NO).
It is possible that the offline reorganization can run faster if you do not
choose “By Selected Index” (or specify the KEYFILE parameter on the
command line).
For ONLINE reorganizations from the Navigator, choose the table, then
Data->Reorganize. On the popup select “By compressing out deleted
rows” and do not check the “Preserve arrival row sequence” and check
“Allow reorganization to be suspended” and “Allow Users to access the
table during reorganization” and “Allow changes to the table during the
reorganization” and set the “Access paths” field to “Maintain during”.
If you prefer the command line, use the command RGZPFM
FILE(R3<sid>DATA/<file>) KEYFILE(*RPLDLTRCD) RBDACCPTH(*NO)
ALWCANCEL(*YES) LOCK(*SHRUPD).
10) Periodically examine the list generated by SAP transaction
DBACOCKPIT, Detailed Analysis, 50 Slowest Queries. Generally, the
SAP indexing strategy is very good, but customer written queries may
select on fields that are not indexes. In particular, look to see if there
are queries over customer created tables that begin with a Z. Often
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July 2015
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these tables are not indexed properly. Check for these same Z tables in
the System i Navigator Database Index Advisor and consider
implementing an appropriate index that includes fields from the
WHERE, GROUP BY and ORDER BY clauses of the query. More than
one index may be useful over a given table.
11) If you are using Independent ASP(IASP) or Cross Site Mirroring(XSM)
review SAP note 568820.
12) If your system is using 3-tier application servers on i see Note 173579
and if using a 3-tier application server on Windows see Note 705886 and
1644051.
13) For SAP Java systems, understand the JDBC connection options from
SAP note 654800.
14) To see if Solid State Disk (SSD) might be used to improve performance
in your SAP environment, use the free IBM SSD analyzer tool. If the
tool indicates your workload might benefit from SSD, flash storage
technology would also be an applicable alternative storage technology.
15) To log current SAP throughput information for later use – for example
when sizing for an SAP release upgrade, use the free IBM Insight tool.
IV
FURTHER SAP ITEMS
The following checks and recommendations may be of benefit within the
SAP application layer.
1) Regularly examine the SAP Alert Monitor through SAP transaction
RZ20 for any reported alert conditions.
2) Review the SAP Table Buffer configuration and performance through
SAP transaction ST10:
 Are tables assigned to wrong buffer? This can occur when a
table is assigned to the SAP Single Record Buffer and is
accessed primarily through an ABAP SELECT statement. The
SELECT does not use the Single Table Buffer. This will result in
a high number of Data Base calls.
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

Tables with very high update counts may not be good
candidates for buffering.
Non buffered tables with mostly read access may be good
candidates for assignment to the Single or Generic Table Buffer.
3) Make sure SAP collector and cleanup jobs are running. Use
transaction SE36 and choose “Standard Jobs” as described in SAP
note 16083.
4) Make sure the SAP ABAP performance improvement to RSDB4UPD
described in SAP note 977676 has been implemented.
5) Review the work process number and configuration through SAP
transactions SM50, SM51, and SM66 to determine if there are too few
or too many allocated work processes.
6) Make sure the SAP Data Dictionary is consistent with the SQL objects
that are actually in the database with transaction DB02. See SAP note
117219.
7) For systems based on SAP kernel release 4.6D or earlier, you may be
using the instance profile setting rdisp/wp_auto_restart to periodically
recycle work processes within an SAP instance on a regular basis.
This setting is not recognized by kernel release level 6.40 or later, so it
may be removed.
V
INFRASTRUCTURE DATA
Make sure to understand and document the architecture implemented for the
complete SAP on i Solution. The following information should be
considered. Record changes as they are made so any effect can be traced
back to the change. This data may be useful when explaining your
environment to consultants or service representatives.
1) IBM Power Systems Hardware Configuration. Power Systems models,
number of active and inactive cores.
2) IBM i LPAR Configuration. For each server, the number of LPARs and
the processor, memory and storage resources associated with each of
them. Also include virtualization environments: Shared processor
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July 2015
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3)
4)
5)
6)
7)
8)
9)
pools, capacity and virtual processors assigned to each partition, and
any VIOS partitions.
Optional Application Server Hardware Configuration:
 Windows: server model, number of processors, amount of
memory. Windows version.
Host names for all LPARs and application servers
SAP System IDs (SIDs) and instance numbers
ABAP/JAVA dual stack or separate stacks
SAP BASIS Release
SAP Kernel Release
IBM i OS Version and Group PTF levels
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SAP NetWeaver on IBM i - Recommendations and Review
July 2015
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