Asset ID: |
1-71-1010176.1 |
Update Date: | 2009-09-27 |
Keywords: | |
Solution Type
Technical Instruction Sure
Solution
1010176.1
:
Rules for SAP on Sun disk layouts
Related Items |
- Sun Enterprise 3500 Server
|
Related Categories |
- GCS>Sun Microsystems>Servers>Midrange Servers
|
PreviouslyPublishedAs
213981
Steps to Follow
Rules for SAP on Sun disk
layouts
Preface
This document is provided to as an aid to avoid disk layout
errors on SAP R/3 on Sun Solaris[TM] systems.
General Rules
-
Separate database logs from the other database storage
-
For database logs, getting write complete confirmation from the
disks as fast as possible is essential.
-
For the sapdatas, use a simple disk layout that is easy to
understand and can be extended without big performance loss. Never
fill the disks more than about 70% so there is room for extending
space and time for ordering new disks/disk subsystems.
Simple Database Log Rules
-
Place database logs on separate disks that contain no other
data.
-
Make sure the remaining disk space of the disks containing the
database logs will remain empty or contains disk space with little
activity. The best way to achieve this is by placing (one or more)
empty, read-only mounted file systems on those disks. Leaving those
disks mainly unused is no waste of money - a slow R/3 system is
much more expensive than buying some disks. Another way to avoid
that database log disks are used for other purposes is to use solid
state disk - they should be chosen to have about the same size as
the database logs.
-
Place each log filesystem or raw device only in the outer areas
of the disks. To do this, allocate space for the logs first. On
empty disks the outer cylinders are used first.
-
Never place two consecutive logs (e.g. origlogA, origlogB or
mirrlogD, mirrlogA) on the same disk(s) because during log switch
time, the old logs are copied to the archive directory while the
new logs are already used for the next transactions.
-
For large size R/3 installations, place database logs only on
disk subsystems with write cache (e.g. A1xxx, A35xx, T3xx), or on
solid state disks, or use the Fast Write Cache option. In these
cases, striping is normally not necessary. However, note that there
may be restrictions if the database server is part of a cluster.
Place the disks containing the database logs in a separate access
path (separate controller, at least separate loop). If there are
only disk subsystems available without write cache, stripe the logs
over 4 or better more disks. Make sure the disks containing the
database logs will never be used for other data.
-
For medium size R/3 installations, placing database logs on
separate write cached disk subsystems may not be necessary,
depending on the I/O write load. As always, place the logs on
separate disks and at least stripe the database logs (use RAID 0)
if they have to be placed on disk subsystems without write
cache.
-
For Oracle, use Oracle log mirroring as recommended by Oracle.
You normally do not need Volume Manager mirroring for the Oracle
logs
ProductSun Enterprise 3500 Server
Internal Comments
None.
Previously Published As
23975
Change History
Date: 2003-05-20
User Name: Administrator
Action: Migration from KMSCreator
Comment: updated by : James Verlee
comment : No comment
date : Feb 8, 2002
updated by : James Verlee
comment : Updated version,spell check, per Knowledge Initiative Program.
date : Feb 4, 2002
updated by : Bernd Finger
comment : No comment
date : May 4, 2001
updated by : Bernd Finger
comment : Document reviewed for issuing as an external infodoc.
date : May 4, 2001
updated by : Wendy Bean
comment : Issued per request of Charles Price.
date : May 4, 2001
updated by : Thom Chumley
comment : No comment
date : Nov 9, 2000
updated by : Bernd Finger
comment : clarified usage of database log disks.
date : Oct 12, 2000
updated by : Bernd Finger
comment : This document is ready to be submitted. It includes
changes made after responses from Bob Sneed
and Bob Larson regarding a previous version of this
document.
date : Oct 11, 2000
updated by : Bernd Finger
comment : Article created.
date : Oct 10, 2000
updated by : Bernd Finger
comment : Article changed.
date : Oct 10, 2000
Version: 0
Product_uuid
29b720d2-0a18-11d6-9865-e60ab6457390|Sun Enterprise 3500 Server
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