Forum Discussion
Ohhh - performance tuning. What a topic :)
You should know the NetBackup™ Backup Planning and Performance Tuning Guide
https://www.veritas.com/content/support/en_US/doc/21414900-146141073-0/v19526785-146141073
This sections mentions waited for empty/full buffer:
https://www.veritas.com/content/support/en_US/doc/21414900-146141073-0/v19528173-146141073
You want as many "waited for empty buffers as possible" meaning backup data is in the buffers (NUMBER_DATA_BUFFERS & SIZE_DATA_BUFFERS) and are ready to be written to tape/disk.
A high "waited for full buffer" is bad, because it means buffers are empty, and backup data is missing from the client, resulting in the tape drive doing start/stop operations (a.k.a. shoe shining). You will never get a 0 "waited for full buffer", but monitoring the running average is recommended. You can't fix slow incoming data by tuning NUMBER_DATA_BUFEFRS/SIZE_DATA_BUFFERS. Instead you need to optimize the data path from client to NBU media servers. Possible culprits are antivirus scanners, network bottlenecks or disk bottlenecks at the client.
A way to test a client minimum run time is running in bpbkar by hand like outlined in tech note :
https://www.veritas.com/support/en_US/article.100006447
It's basically tells bpkar to read the backup data and throw the read data to /dev/null. Meaning if it takes 6 hours for bpbkar to read all data and throw it away, you will never ever be able to transfer the data to Netbackup media servers faster, unless optimization is being done on the client.
Best Regards
Nicolai
- davidmoline2 years agoLevel 6
Further to the excellent advice already provided - can you change the backup to write multiple streams at once?
The backup looks like a MS-Windows type policy with two volumes to backup. If these can both run together and write to the same tape drive (increase the multiplexing on the STU), then you should get better performance.
This should all be covered in the tuning guide already recommended.
FInally - you seem to have lots of disk available - can you convert the backup to initially write to disk, then duplicate to tape. The backup should complete much faster, and then the duplication to tape isn't affecting the client performance.
Cheers
David
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