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NETBACKUP 6.5.5 using 2 drives simultaneously

Created: 16 Apr 2010 • Updated: 16 Oct 2010 | 3 comments

Hello, I need to know if it is possible to backup a client (which is also a media server, windows 2003 with NBU6.5.5, and that have 2 LTO4 drives attached directly to it) using both drives at the same time for a single policy. I have 50 Tb to backup which is SAN attached to the client (which is a media server). I mean can I direct a policy on 2 drives simultaneously!

Thanks for any ideas.


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J.H Is gone's picture

The only way you can have a backup of one server go to two drives at once is to have 2 jobs running at once..
If you set up the storage unit to have 2 drives and only allow 1 job per drive (meaning no multiplexing) you will then force the backup to use two drives for each job..... but you have to have 2 jobs.

Now to get two jobs you need to do something in your backup selection of your policy.
If you are backing up 2 or more disk C, E, F, then have one stream for each.
If you are backing up 1 disk E then you need to break that disk up into more than one stream.

New Stream
and say anything starting with 0 to 9
New Stream
and say anything starting with a to h
New Stream
and say anything starting with i to z
(your choice as to how to break it up, you just want to make sure that not only cover dir's that are there now, but dirs that may be created latter)

this would give you 3 streams
2 streams will start, one to each drive
and the third stream would wait for one of the other two to finish.

This will help in the way that if a job dies it only restarts what it was working on not the whole drive.
this may hurt  in the fact that you have 2 jobs gathering data and sending to backup at the same time, it may bog down the server, but you will have to analyze that to see if it is an issue.

I don't have to know how to spell....I work on Unix.
NetBackup 7.0.1 - AIX & Windows

J.H Is gone's picture

Do you need 2 drives?   Most servers cannot keep a drive busy with just one drive, and you want to try to keep the drive spinning.

So instead of two drives, you could set up the backup selection as I stated above, but
have the storage group just one tape drive with multiplexing turned on.  Now you have 2 jobs running but are only using one tape.

In the same line... if you are already backing up with a common storage unit that uses multiplexing to the tape drives, you can just use the same storage unit  and just set up the policy to do more then one job.

I don't have to know how to spell....I work on Unix.
NetBackup 7.0.1 - AIX & Windows

mph999's picture

J.H is correct, but in the fact he has come back with a second post he has demonstrated something - This needs planning carefully and  is not really a 5  minute job to do.  Also, I personally don;t think there is enough information.

For example:

1.  What is the data (eg. oracle DB, regular files, large files, very small files
2.  How fast can you read the data off the disk
3.  How are the 2 LTO4 drives connected, that is, how many connections are coming out the back of the server.
4.  How is the data layed out on the disks

If you have say 4 directories 1,2,3,4 but they are on the same physical disks,  attempting to backup more than one area at once will hit performance, as the disks will be maxed out.

If (for example) dir, 1,2 are on separate spindles to 3,4 you could backup 1,2 as one job and 3,4 as another:

New Stream
New Stream

By then reducing the number of jobs allowed to each drive to one, two drives will be used, with data from each drive coming off different disks.

If the SAN can support this throughput, then that is good.

Another question is how fast is it going at the moment.  I presume you are using only one drive.

If this is ging <40MB/s (approx) then you can't even drive one drive fast enough, and would perhaps need to consider multiplexing the data from different disks but just to one drive, to get the average speed up.

50TB is a large amount of data, running to just two drives.  How much time do you have for this to complete.  If this is a "single backup" then you may wish to consider using checkpoints also.


Regards,  Martin
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