Archivelog Backup affecting SAP Performance

[Former Member]

Hi,

Everytime our Archivelog Backup is run, SAP will slow down. Does anyone knows where could have gone wrong?

Regards,

Annie

Edited by: Annie Chan on Dec 3, 2008 10:25 AM

[markus_doehr2 · Accepted solution]

What operating system do yo use?

Are archive logs and database on different disks (not partitions)?

Markus

[Former Member · Accepted solution]

Hi Markus,

We are on AIX 5.1, SAP 46C, SAP Kernel 700. It's running on SAN hence different disks.

Using IBM Tivoli TSM. I wonder why it is causing so much Concurreny activities which I can view it in Oracle Grid Control.

Regards,

Annie

[markus_doehr2 · Accepted solution]

> We are on AIX 5.1, SAP 46C, SAP Kernel 700.

I seriously doubt that you run a 7.00 kernel against a 4.6c system

> it's running on SAN hence different disks.

ok

> Using IBM Tivoli TSM. I wonder why it is causing so much Concurreny activities which I can view it in Oracle Grid Control.

Concurrency to what?

Markus

[Former Member · Accepted solution]

Haha, you are right. I typed too fast. BR*Tools 7.00 I mean.

For the Concurreny, it shows Top SQL and Top Sessions. However, I cannot tell much from the information. I can only see that it's SELECT activities in Top SQL with userid that I don't understand. Top Sessions are sap processes.

During the backup, the user activities are normal but the avg. response time will increase by hugh percentage. Once the backup is completed, the avg. response time is immediate back to normal i.e. < 1000ms.

Thanks for the prompt response.

Regards,

Annie

Edited by: Annie Chan on Dec 3, 2008 12:47 PM

Edited by: Annie Chan on Dec 3, 2008 12:48 PM

Edited by: Annie Chan on Dec 3, 2008 12:49 PM

[markus_doehr2 · Accepted solution]

Haha, you are right. I typed too fast. BR*Tools 7.00 I mean.

No offense

So I assume you´re running Oracle 10, right? If yes, then I have to tell you, that your are running an unsupported database/OS/kernel combination.

See note 156548 - Released operating systems SAP kernel 4.6x ORACLE

- the "normal" old 4.6D kernel is not supported with Oracle 10

- the 46D_EXT kernel is only supported on AIX 5.2 onwards.

According to

http://www-111.ibm.com/software/support/lifecycle/PLCDetail.wss?synkey=U181851I98558E72-S979278Z0242...

AIX 5.1 is also out of support (hence Oracle 10g not supported).

The reason for your problem may be, that the backup of the archive logs "trashes" the filesystem cache, check your AIX kernel on how much space you reserve for this.

Apart from that I highly suggest you upgrade to a supported combination.

Markus

[Former Member · Accepted solution]

Hi Markus,

Oh, my typo mistake again. We are running Kernel 46D_EXT (2364), AIX 5.3, Oracle 10.2.0.2.

I saw this in OSS 156548:

SAP KERNEL 4.6D_EXT 64-BIT:

ORACLE 10.2 64-BIT AIX 5.2 10,12,21,7

ORACLE 10.2 64-BIT AIX 5.3 10,12,22,7

ORACLE 10.2 64-BIT AIX 6.1 10,23,7

ORACLE 9.2 64-BIT AIX 5.1 24,4,5,6,7,8

ORACLE 9.2 64-BIT AIX 5.2 25,5,6,7,8

ORACLE 9.2 64-BIT AIX 5.3 20,26,8

It is supported. phew

I will check out the AIX kernel.

Thanks for the insight 😃

Regards,

Annie

Edited by: Annie Chan on Dec 3, 2008 1:38 PM

Edited by: Annie Chan on Dec 3, 2008 1:40 PM

Edited by: Annie Chan on Dec 3, 2008 1:45 PM

[markus_doehr2 · Accepted solution]

> Oh, my typo mistake again. We are running Kernel 46D_EXT (2364), AIX 5.3, Oracle 10.2.0.2.

Good! )

you may also check that the oracle parameter

filesystemio_options

is set to "setall" if you use JFS2 as filesystem

See note

948294 - AIX JFS2: mount options to use with Oracle 10g

how to configure that. This may also be a reason because in case a backup runs the normal operation and the backup will displace the cache permanently and so slow down the system.

Check the kernel parameters

strict_maxperm

minfree

Markus

[sebastian_sebaraj · Accepted solution]

1.Are you writing to DISK POOL or writing to TAPE directly when you use TSM?

2.Are you using the same LUN both for Database and DISK POOL in the SAN

3. How much cache allocated in your SAN for WRITE/READ

4. If you have statspack installed , you could take a snapshot before,during and after and post it

5. Are you using RMAN to take a backup or SAP Tools to backup

6. List SAR output before,during and after and see heavy whether heavy IO wait

[Former Member · Accepted solution]

Hi Markus,

We have implemented OSS note 948294 - AIX JFS2: mount options to use with Oracle 10g and confirmed filesystemio_options is set to setall. In addition, I have also increased the SAP buffers. After implemented the above, the performance has improved alot. I noticed there are lesser disk access at the AIX level which could be due to increase in SAP buffers and lower CPU usage as well.

Thanks for the advice and information.

Regards,

Annie