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watcharapongs's avatar
10 years ago
Solved

Improve Exchange DAG backup performance

Hi All,

We are backing up Exchange 2010 DAGs and it takes more than 27 hours to complete data sizew 4TB (70-80 MBps). Is there a way to speed up the backup performance?

 

The system environment:

- 3 exchange servers, MBX1 (active), MBX2 (active) and MBX-DR (passive copy).

- Using a virtual name as backup client name in the NBU setting, MBX-DR as DAG backup prefer server.

- Backup using LAN to Master server which tape library connected to.

- No backup multistream enabled.

 

Here is my questions?

- Is it possible to set up MBX-DR as NBU media server? Is it support my Exchange environement?

- Is the multistreaming backup could improve the backup speed?

 

Your recommendation is appreciated. Thank you.

 

  • You were asking about Multistreaming in your opening post.
    Have you tried it yet?

    I find that Multistreaming provides 'quick win' while other performance issues outside of NBU are being investigated and addressed.

  • Yes. Multistreaming can most certainly improve overall throughput. Try 2 simultaneous streams as a start. If that goes well, try 4 streams. We normally recommend max 4 streams. There are obviously many factors that contribute to poor performance, such as badly fragmented db's, poor lun layout, underpowered /overburdened servers, network congestion, etc etc. Start with multistreaming while you investigate all other components in the backup path.
  • Number on performance tweak is to configure NUMBER_DATA_BUFFERS/SIZE_DATA_BUFFERS on media servers (and master if it act as media server)

    In [INSTALL_PATH]/netbackup/db/config/

    create these two files with nodepad:

    SIZE_DATA_BUFFERS - file must contain value 262144 in it.

    NUMBER_DATA_BUFFERS - file must contain 256 in it

    Both files must be named exactly as above - ensure the files has no extension like .txt

    Back ground reference:

    http://www.veritas.com/docs/000016306

     

     

     

  • Are you backing-up the same mailstore databases from all three DAG nodes?

  • Hi Nicolai,

    Thanks for your suggestion about the backup parameters, I'm going to try that.

    I'm thinking of  setting up NBU on Exchange DR server (MBX-DR) as NBU media server but I'm not sure whether the NBU could support this configuration or not.

     

  • Setting up MBX-DR as media server may help if you/Exch can guarantee that this server will always be used for the backup.

    Note that 'preferred ' does not mean 'fixed'.

    Please only config buffers if you are 100% sure that slow performance is not caused by issues on the client or the network (as per my previous post ).
    If bptm is already waiting for full buffers from the client, then increasing buffer size will mean that bptm will wait longer for full buffer.

  • Hi Marianne,

    Your were right. I've checked on NBU and found data was being transferred from various servers (MBX1, MBX2 and MBX-DR) to NBU Master server but almost was from MBX-DR which is a preferred server.

    Thanks for you suggestion.

     

  • You were asking about Multistreaming in your opening post.
    Have you tried it yet?

    I find that Multistreaming provides 'quick win' while other performance issues outside of NBU are being investigated and addressed.

  • Waiting for a larger full buffer does not bean backups will be slower.

    Writing fewer larger buffer than many small buffers reduces wear on the tape drives.  Tuning buffers should always be done to get overall good tape drive performance. But tuning buffers alone will not solve bottleneck on clients or network.