Re-using netbackup tapes

[AQasir]

I am running NBU 6.0 MP6 in my shop and have been running NBU for some time.  Over time some of the configuration (storage unit names, robots, tape drive names, policies....etc) have changed. But throughout all of this the retention levels for my cumulative-incremental, weekly full, and monthly back ups have remained the same (example: RL4 for cumulative incremental, RL5 for weekly full, RL6 for monthly full). I know that NBU has logic built in which helps the software decide which tape it will write to. I believe that backups with different retention levels are not written to the same tape.  I also believe that backup types are not co-mingled, so for example a oracle policy will not write to a windows tape. But what about when a windows policy writes to a scratch tape [the tape is now labeled a windows tape]and then at a later time (after storage unit name has changed due to changes in infrastructure) we attempt to write to the same tape with the same windows policy or even a different windows policy with the same retention level? 

I have tons of old tapes that still have space on them and I want to utilize the space to its fullest but I cant due to some logic that I haven’t understood yet....please help.

[J_H_Is_gone]

welll I think part of that is wrong.

it can tell NB to not mix retention levels on the same tape ( but you can tell it to as well).

I have tapes with both Standard (unix) backups and Windows_NT backups on them so it can mix them just fine.

Have you checked to see if any of the tapes are frozen?

One of the things is who owns the tape.  if a meida server owns the tape, I think only that server will write to it.  So have you retired any media server?

[AQasir]

Thanks for the quick response...Just so that I can understand your response I have some more to add/ask.

NBU provides the ability to co-mingle backups with differing retention levels....You are correct and I do see this option when I go into the host properties of the master server. Under "Media" there is an option for Allow multiple retentions per media. I purposely choose not to allow this.

NBU can be configured so that  different OS's can be written to the same tape (ex: Oracle and WIndows on one tape)...is this controlled via Volume Pools..?  In either case I like the way I have it setup to write an oracle job to the oravle volume pool and a windows job to a windows volume pool.

Finally, how do I find out who owns the tape? Is there a way to get different media servers to write to the same tape (not necessarily at the same time). So for example lets say I had a file server "A" which was also a media server. Server "A" wrote to tape "A1" but a few months later I decommissioned server "A" and now have server "B" which is a media server. Can I get server "B" to write to tape "A1" even though tape "A1" was associated to server "A"?   I think you did hit the nail on the head...I should be asking how do I get different media servers to write to the same tape!

P.s. I have confirmed that my tapes are not full and that they are not frozen.

[J_H_Is_gone]

as far as I know you cannot get two "working" media servers to write to the same tape.

the tape can only be owned by one at a time.

if you go to the gui and media on the left.

in the right hand screen you can add the column of "media owner"

this tells you who made the images on the tape.

if you need to change who owns the tape

bpmedia -movedb -newserver <newhostname> -oldserver <oldhostname>

do that to one and check the gui again to see if it changed ( this is the command I used on 5.3 - I don't think it has changed).

[Dion]

From version 6.5 onwards you can set up Server Groups where you can share media between different hosts.  Another thing, when all the images on a volume and the tape expire, the tape is not owned by any media server.  Only once a tape get assigned with data does it become "owned" by the media server that used the tape.

Cheers

[AQasir]

Hinchcliffe and other contributors,

Thank you for your responses. I performed several corrective steps and am now getting better control over my tape utilization. Thanks for your help.

However I still have TWO things going on in my environment that seem to go againt what we all believe should be....or perhaps I am still overlooking something.

1. FOr the first issue take the following two media as an example:

VMC095 csapuslic-010 WINDOWS 5  12 8/20/2008 1:23:19 AM csapuslic-010 Active MPX 33119749

VMC051 csapuslic-010 WINDOWS 5   1 2/18/2008 9:12:11 PM csapuslic-010 Active MPX 41417599

Here both media have a retention level of 5 and both are active. Both tapes have space left on them and belong to thwe windows volume pool. Both are in the same robot and are owned by the same media server (csapuslic-010). I set the mount count on VMC051 to "1" and the mount count for VMC095 to "10" expecting that VMC051 would be written to since it has a smaller mount count. But instead when I came in this morning I saw that VMC095 was written to. Can anyone explain why...or suggest other things that I should look into.

2. For the second issue take the following three media as an example:

VMC040 csapuslic-010 WINDOWS 4  10 8/10/2008 1:23:19 AM csapuslic-010 Active MPX 200000000

VMC041 csapuslic-010 WINDOWS 4  15 2/17/2008 9:12:11 PM csapuslic-010 Active MPX 150000000

VMC042 csapuslic-010 SCRATCH     200 

Based on the logic that VMC040 and VMC041 are in the same robot, belong to the same retention level and belong to the same media server I expect that tape VMC040 will be the 1st tape to be written to...and in this particular case lets say that it is. Once VMC040 fills up and is marked as full and there is still more data to be backed up I would expect that VMC041 will be used but it isn't. For some reason Netbackup seems to have a preference for the scratch tape to finish the rest of the backup.

However, if I don't have a scratch tape in the robot then the backup correctly goes to VMC041 or any other tape of the same retention level in the same volume group belonging to the media server.

Can anyone confirm this or explain what I need to change in my setup so that thwe backup preference is for another used tape before it goes to the scratch tapes.

[Andy_Welburn]

1) I would've expected the same as yourself on this one!

2) The same happens for us also - whenever NB fills a tape it always seems to prefer to finish it's current round of saves on 'fresh' media if available instead of one that is partially full, as you have discovered - altho' I don't see why.

From 6.5 (I believe) there is a setting on the Volume Pool that allows you to restrict the number of partially full media within that pool. From the Admin Guide:

"...

Does not apply to the None pool, catalog backup pools, or scratch volume pools.
Enter or specify the number of partially full media to allow in the volume pool.
The default value is zero, which does not limit the number of full media that are
allowed in the pool.
NetBackup writes data only to the number of partially full media.
When the number of partially full media is reached, NetBackup queues backup
jobs until media becomes available. If a media becomes full, NetBackup assigns
another media for use if one is available in the pool or in a scratch pool.

..."

[AQasir]

Andy,

Thank you for your response...now I don't feel like a complete failure knowing that others are experiencing the same problems. I had not responded to your message hoping that a symantec guru would chime in an let us know why this is happening and how we can fix the problem. I hate to manage tapes so closely due to this issue !!!

Anyone out there in symantec that can explain this situation a little better ? Anyone out there that can recommend a better way of managing tapes and writing to older tapes before new ones ?