Multi Streaming Data and Multiplexing to disk
As Marianne says i think the
As Marianne says i think the original question has been answered but let me clarify and cover the drives too ...
When writing to disk the maximum number of streams is governed by the storage unit itself only so the number you set here is dependant on the capability of your backup server (disk speed, memory and network)
The multiplex value in a schedule relates to tape backups only.
When backups are duplicated from disk to tape they run one image at a time and so do not multiplex onto the tape - as a result you do not need to set a multiplex level for tape if using disk staging
Your output shows two tape drives - the first shows UP but i do not see a status for the other one. If it is also UP and does not have a tape stuck in it or anything similar then as long as you tape storage unit is set to have 2 concurrent drives in it both should be used
Hope all of this helps
Comments
Backup direct to disk will
Backup direct to disk will always be non-multiplexed.
Relocation from disk to tape should have a multiplexing of 1. Remember you can have more than one storage unit for a set of tape drive (use one for duplication and one for backup direct to tape).
You should also limit the amount of concurrent IO to the disk storage unit. Try a value of 20 concurrent IO and tune from there.
Multi stream backup to disk will be single stream on tape. This is a issue Symantec know and is working on to resolve.
Best Regards
Nicolai
Assumption is the mother of all mess ups.
If this post answered your'e qustion - Please mark as a soloution.
Ok thanks for the info
Ok thanks for the info Nicolai.
Are backups then queued when being backed up to tape?
If I have 2 tape drives is it possible to create 1 storage unit group containing both tape drives?
Let me clarify :-D If you
Let me clarify :-D
If you write 5 stream from e.g. a database backup to disk, all stream will write concurrent. But when the data is staged to tape and you need to restore the data from tape it will be restores as if it was a single stream of data. Netbackup does not have the logic to spread multiple stream to disk to multiple tape drives.
Yes - two tape drive from two storage unit can be put in a storage unit group.
Assumption is the mother of all mess ups.
If this post answered your'e qustion - Please mark as a soloution.
Ok thanks Nicolai. Would that
Ok thanks Nicolai. Would that be the recommended setup to make the best use of both drives in a tape library unit?
Yes I would think so - unless
Yes I would think so - unless there are specific requirements. You don't even need to put the drives in a storage unit group. A single storage unit can point to two drives.
Assumption is the mother of all mess ups.
If this post answered your'e qustion - Please mark as a soloution.
I have selected the tape
I have selected the tape robot when setting up storage unit but it seems that only one of the drives is selected anytime when performing a backup.
This drive is only ever used HP.ULTRIUM5-SCSI.000 even though there are 2 drives available.
Look at the Storage Unit
Look at the Storage Unit config for the TLD0-hcart2 STU - how many concurrent drives?
This is what Nicolai was trying to say over here: https://www-secure.symantec.com/connect/forums/multi-streaming-data-and-multiplexing-disk#comment-7815331
PS: I believe your question about multistreaming and multiplexing to disk has been answered....
Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links
As Marianne says i think the
As Marianne says i think the original question has been answered but let me clarify and cover the drives too ...
When writing to disk the maximum number of streams is governed by the storage unit itself only so the number you set here is dependant on the capability of your backup server (disk speed, memory and network)
The multiplex value in a schedule relates to tape backups only.
When backups are duplicated from disk to tape they run one image at a time and so do not multiplex onto the tape - as a result you do not need to set a multiplex level for tape if using disk staging
Your output shows two tape drives - the first shows UP but i do not see a status for the other one. If it is also UP and does not have a tape stuck in it or anything similar then as long as you tape storage unit is set to have 2 concurrent drives in it both should be used
Hope all of this helps
Authorised Symantec Consultant
Don't forget to give a "Thumbs Up" or mark as "Solution" if someones advice has helped you.
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