Tape drives dedicated for restore in Netbackup 7 using SSO

[krish06]

Hi All,

I have a query regarding tape drives dedicated for restore in Netbackup 7 using SSO.

I have 5 Media servers and 13 tape drives with shared storage option. I want to dedicate one tape drive out of 13 to be used for only restores.

   1. Using "Maximum concurrent write drives" concept in ecah medias server: If one media server goes down, then I need to manually change this setting to make use of the tape drives. And this is as equalent as dedicated tape drives.

   2. Looking for an option to use the  tape drives for a group of media servers.

Please help me here..

Thanks

Krishna

[J_H_Is_gone]

First - NO you cannot dedicate one tape drive for restores - no way to do that - as the media server who did the backup will want to do the restore.

Now you have 13 drives and 5 media servers. 13/5 = is 2.6

So say you create a storage unit for each of the 5 media servers and that storage unit only as 2 drives 2 x 5 is 10  - so say two of them get 3 drives that takes you up to 12 leaving one drive free.

But now you need to do a restore - the media server doing the restore is going to use one of its 2 or 3 drives for the restore - say it is a server with 3 drives in its storage unit and all 3 drives are in use for backups - it is not going to use that 13th drive because it is only allowed to use 3 and all of those are already in use.  The server has to wait for one of the 3 drives to become free.  So you might as well assign that 13th drive to a storage unit as well.

Each storage unit belongs to only 1 media server so there is no sharing of a storage unit to more than one media server.

You can create a storage unit group - this can contain storage units from more than one media server.

You can then set how that storage until will be used by saying use the first storage unit in the group that is not down or out of tapes (so the order you add them to the group matters)

So you have a SG with mediaserverA and mediaserverB

You assign that storage group to your policy that you want to use A, then if A is down it will use media server B, but it does not get A's extra 3 tape drives.

[Zahid_Haseeb]

Hello J would you kindly share your point of view above more please ?

Actually i have 6 Tape Drives attached with my Tape Library and i want to dadicate atleast one Tape Drive with a particular Backup Policy. Whats your suggesstion

[krish06]

Hello J,

Thanks for your update.

So,

Using shared storage option, I will share 13 tape drives to all 5 media servers.( each server will see 13 tape drives). Using "Maximum concurrent write drives" option in media servers, I will choose the option as 2,2,2,3,3 for Medis servers A1 to A5 (so 12 drives at any time can be used for writing) and one drive will be left which will not be available for writing purpose and can be used for restore purpose only.

Will this works? However it do have the some limitation in practical usage. :)

Thanks

Krishna

[J_H_Is_gone]

When you create a storage unit you tell it how many drives can be used at once and that storage unit belongs to a media server.

So if you create a storage unit with 2 drives  ... and you want to do a restore....

The restore will use the same storage unit for the restore - which means the media server is still limited to 2 drives.

Now if you are doing backups and the storage unit has 2 drives, and the media server is using both of those drives for backups.... then you start a restore.... there are no drives available in the storage unit for it to use.  The media server has to wait for one of those drives to become free before it will start the restore.

So you can just go ahead and assign all 13 drives to storage units, because it will not matter that you have one free.  The Media server that did the backups will do the restore and use the same storage unit to do it.

This question has been asked many many times and the answer is always the same - you CANNOT reserve a tape drive to be used by all restores.

[AbdulRasheed]

Hi J,

   Actually the concept of Storage Unit is applicable only for write operations (backup, duplication destination etc.). Read operations does not use the concept of Storage Unit, it simply picks up the medium (tape) and media server from the catalog. You are correct in stating that the same media server which did the backup will be used for restores, but 'not the same storage unit'.

   Thus, if you have a media server with three tape drives and set maximum concurrent write drives to 2, you are effectively reserving a tape drive for restores or read side of duplication jobs. This had been a common practice since NetBackup 3.2 days.

Hi Prasad,

   Do you let end users (non-administrators) restore from their own backups? If yes, you can reserve a drive for restore by reducing the maximum concurrent drives in a storage unit.

   If the restores are done by NetBackup administrators I wouldn't recommend wasting a drive like that. NetBackup has evolved so much over the years. You have the ability to increase the priority of your restore job and then suspend enough jobs to free up a drive. The freed drive will now be used for restores.

[J_H_Is_gone]

I have seen this question asked many many times. and each time it is the same NO you cannot reserve.

I have never seen anybody give that answer before.

So OK, ignore what I said and see if this works for you.