Performance didn't improve with increasing the number of drives

[jibujacob]

Hi,

Initially I was using 4 L4 drives to backup my 2TB oracle database. It took almost 2 hours and 2 minutes for the backup using all 4 drives simultaneously.

Expecting a reduction in backup time, i increased the number of drives to 6. Eventhough 5 out of this 6 drives are used for writing, still the time for backup remains as same..no reduction....

Can i do any other tuning to reduce the backup time by improving speed of writing..

Regards,
jibu

 

[tariq.kaifi]

I maybe pointing something obvious, but did you increase the number of channels in your RMAN?

Also, check for the load on Oracle server during backup, like processor status, disks I/O, etc...

 

[Harry_Redl]

Hi,

well ... let's do some math ...
2TB = 2097152MB - if you back this up in 122minutes, then your total transfer rate (in MB/s) is 2097152/122/60~286.5MB/s
Native transfer rate of single LTO4 drive is 120MB/s (this is without compression) - so it seems your 4 drives are more than enough for this data flow (seems even 2 drives can do the job in similar time). So adding another drive is not the way (as you have found yourself).
Problem can be in the source system (check the load during the backup) - disk array, storage agent configuration, buffers, SAN ... whatever.
This needs deeper analysis ...

Harry

 

[jibujacob]

Hi Tariq,

I am not using RMAN, i am just stopping the database and then taking a storage level flash (storage level copy of OS files) and then taking these copied OS files to tape....

My TSM client for backup runs in same machine for the TSM server. It's specifications are :

Processor Type: PowerPC_POWER5
Processor Implementation Mode: POWER 5
Processor Version: PV_5_2
Number Of Processors: 2
Processor Clock Speed: 1898 MHz
CPU Type: 64-bit
Kernel Type: 64-bit

Will any upgrade in this will result in better performance. My problem is that my backup window is very less.....

Regards,
jibu

 

[tariq.kaifi]

Well Jibu, then you need to look as Harry suggested, (but you have good enough speed for LAN-free), it can't be just one thing.

How less is your backup window? 2 hours seems sufficient to me for 2 TB database.

 

[jibujacob]

Backup Window: I need the least possible window.....i target around 90 minutes.....with 6 drives...

Harry's sugeestions are in my mind...Still i am not clear why 6 drives are not used

Regards,
Jibu

 

[tariq.kaifi]

Can you post the values for max number of mount points and resource utilization?

 

[jibujacob]

maxnump is 10
resourceutilization is 10