Re: TSM Tape performance

  • From: Mladen Gogala <gogala.mladen@xxxxxxxxx>
  • To: oracle-l@xxxxxxxxxxxxx
  • Date: Thu, 28 Apr 2016 12:59:37 -0400

Hi Sanjay,

My responses are in-line:

On 04/27/2016 03:33 PM, Sanjay Mishra (Redacted sender smishra_97 for DMARC) wrote:

Hi

I had a environment which is 11g R2 RAC and have 15 database running on it. Some are very big double digit terabytes and so rman backup to TSM tape library is taking long time. We worked with TSM and got dedicated vlan backup interface but it is not behaving correctly as sometime backup work good but another backup after one backup take 5-6 time more. If using regular interphase the performance is constant. Os level backup using dedicated gigabit vlan backup interface is having not issue.

1GB LAN is simply too slow to handle double digit TB. What you need is 10GB or better (bonded interfaces). With 1GB NIC, you can reasonably expect between 300 GB/hr and 350 GB/hr. It will take you 3 hours to backup 1TB. With "double digit TB", it will take you triple digits in hours. That will give a new meaning to the notion of weekly backup. However funny it may sound, you should probably do incremental level 1 backup into the FRA and then backup FRA once per week.


Only RMAN backup is the issue. Can someone share any experience as how to monitor and trace the issue. Ticket was opened with Oracle support but they found nothing on both OS (Using OEL) and Database (11.2.0.4). TSM team saying that OS level backup has no issue and it is only rRMAN which is having issue. Moreover RMAN work good sometime but having intermittent issue.

So if someone share how they think this can be handled or any of their experience.
First and foremost, the database of that size should not be run without a standby. The first layer of protection for such a large database should always be a surviving RAC instance. The second layer of protection should be standby and the 3rd layer should be backup. Now, with 20GB/sec, Commvault can achieve 8TB/hr with deduplication and without compression and 9.2 TB/hr with compression only. The client has opted for deduplication, since the savings in storage are significant. 9GB/hr should be enough to backup a very large 100TB database in about 12 hours. Backups with compression is very CPU intensive, so it should be running on standby db, not the primary one. However, the infrastructure you will need is rather significant. 1 GB LAN will definitely not cut it. If you don't have such a wide pipe, you may consider putting a VTL on the DB server and connect the disk library to the DB server by 16GB F/C controller. VTL will copy it to the tape, when the allocated disk library fills up. Commvault software suite can do all of the above. However, you will still need good infrastructure



TIA
Sanjay

Regards

--
Mladen Gogala
Oracle DBA
Tel: (347) 321-1217

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