Multi Data Stream Backup and Restore

[Dylan_G]

Greeting to all.

I am using NBU 5.1 on unix with a 2x LTO2 drive library.

My question is, if I use multi data stream option to backup my data over 2 drives, will my restore of all data will automatically using both drives at the same time?

example:
NEW STREAM
/
NEW STREAM
/data1
NEW STREAM
/data2
NEW STREAM
/data3

while start backup, i can see backup job on both drives. if I to restore all filesystem, will it utilize both drive as well?

ultimate question: it is known the multi data stream improve backup performance, but what about restore performance?

Thanks in advanced.

[MayurS]

Hi,

There seems to be some confusion.
Mutiple streams will not use Multiple drives.
Check what the other drive is backingup.

and restoration will happen from only one drive and not sumultaneously from two drives.

\Message was edited by:
Mayur Shinde

[Dylan_G]

in this case, how to enable a backup job to run on 2 drives? should it be multiplex enabled also?

[MayurS]

Hi,

There are two Concepts Media Multiplexing and Multiple copies or Inline Copy.

Multiplexing will write backups of multiple clients to the same tape.

Multiple copy/ Inline tape copy will write backup of same client to Multiple Tapes.

What is your requirement ?
You want backups to happen faster ?
Or you want to create two copies of whatever you backup ?Message was edited by:
Mayur Shinde

[MayurS]

how to enable a backup job to run on 2 drives ?
1) You wil have to specify the number of copies that you want to maintain of a backup
This value is set in Global Attributes of master
2) In the policy>schedule>attributes you will have to mention the Number of copies under Multiple Copies,

[Dylan_G]

I want a policy (contains multiple filesystem) to utilize both drives during backup. Also, allow it to use both drives while restoring full backup.

thanks.

[MayurS]

Hi Dude,

allow it to use both drives while restoring full backup. -

This is not possible

Please tell me why you want a policy (contains multiple filesystem) to utilize both drives during backup.
Any specific reason ???

[Dylan_G]

Of coz the reason is to speed up the backup performance.

so it is no way to make a recovery concurrently from multiple drives? even /data1 on tape1 and /data2 on tape2.

[patrickkuah]

correct me if i'm wrong here...

I think it is possible as long as u execute two restoration jobs. The first job from /data1 and the second job from /data2...
NBU will mount the respective tapes as long u have the drives...

patrick

[MayurS]

so it is no way to make a recovery concurrently from multiple drives? even /data1 on tape1 and /data2 on tape2.
---
In this case you will have to initiate two separate restoration jobs..

Patrick - Correct me if i am wrong.

[Stumpr2]

Hello Dylan

Yes you can backup to two drives while using multistreaming as long as you have the max number of jobs per policy set to 2 and the global max jobs per client also set to a value greater than 1

NetBackup will create a separate and unique image for each stream that it backs up. If you want to restore using two drives then you need to initiate 4 independant restore requests
/
/data1
/data2
/data3

be careful when using multistreaming to NOT attempt to multistream the same physical drive or else you will get drive thrashing and it will slow down the overall backup.Message was edited by:
Bob Stump

[MayurS]

be careful when using multistreaming to NOT attempt to multistream the same physical drive or else you will get drive thrashing and it will slow down the overall backup.
-
What is to be done not to multistream to the same physical Tape drive ?

[Stumpr2]

I was referring to the disk drive not the tape drive.
If you have a 200GB physical drive that has been segmented into various mount points then you need to use $NEW_STREAM to group all of the segments sharing the 200GB drive into one stream. If drives D:\ and E:\ are on the same physical drive then the filelist may look something like this:
NEW_STREAM
C:\
NEW_STREAM
D:\
E:\
NEW_STREAM
F:\
NEW_STREAM
G:\

see how I've kept D:\ and E:\ together in the same stream?
I would not want to simply enter ALL_LOCAL_DRIVES in the filelist and enable multistreaming because then the D:\ and E:\ drives may have their I/O thrashed as they may both be trying to be read from at the same time for creating the backup images.Message was edited by:
Bob Stump