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Partitions should be banned

Created: 03 Dec 2010 • Updated: 03 Dec 2010 • 6 comments
pkh's picture
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The only reason I can think of for using partitions in a tape library is to force BE to write to a particular tape or to a particular set of tapes.  This is a desirable outcome for some organizations.  However, this comes at a price.  When more tapes are needed and there is none in the targeted partition, BE will not be able to get the tapes from another partition even if they are available and the job will fail.  Backup job failures are bad for the organization.  The reasons why this is so are covered in the second paragraph of my article

If the library is not partitioned, then BE can get a tape from another media set and complete the job.

BE will only take a tape from another media set if there are insufficient tapes in the targeted media set.  This could be due to setting the OPP (overwrite protection period) incorrectly so that there is no overwriteable tape available or the data has grown so much that it exceeded the number of tapes allocated to the media set.  Having partitions only worsen the situation by preventing BE from taking tapes from other partitions and thus causing the job to fail.

It is my contention that partitions in a tape library should be banned.  They are hazardous to your backups.  Do you agree or don’t agree?  Take the survey to the right of this blog. 

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Hywel Mallett's picture

I'm not sure about banning them, but my opinion is that they are often used where they are not needed, then people encounter issues they didn't expect, and that issue wouldn't have occurred without the partitions.

I'm sure that they are useful for something, but until I know what that something is, I won't recommend using them!

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CraigV's picture

We use them...reason being, the users get told which tapes to remove from which slots on which days. This makes it easier for them, considering they are not IT staff.

That said, I like organisation...suits me really well, and having partitions means I get the organisation I want. I am able to point out clearly what jobs are targetted to which partitions.

I manage my media well...which means that there is no need NOT to have partitions...there are always tapes available, as my append/OPP is correct.

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Ken Putnam's picture

If used properly they are great, but many who get into trouble have not bothered to train themselves on how to understand or use them.

If you label tapes like  Daily,  Full - Wk 2, Monthly  etc (like one place I worked), then partitions are almost mandatory

If you only use numeric tape labels, and let BackupExec manage what media set each volume belongs to, then partitions are, indeed,  a bit of overkill

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Siddh's picture

We have 7 libraries or organization I fell much comfort with creating partitions and allotting the slot for the particular job.  This helps me in recognize the tape when I am not in office and helping my colleague on call.

As we are using grandfather media policy we have to change the tapes after full backup for sending it to offsite location in this case it’s easier to identify the tape used in full backup. I can easily say this particular slot tape is used for backup.

So I feel there is no meaning to band this thing, it is helpful. Yes creating partitioning is depending on what backup structures you have if not require then don’t do the partition.



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Test your backups to make sure they will get you back up! Because a backup failing is just as bad as failing to backup!

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Colin Weaver's picture

The real issue here is not Partitions - it is that a lot of Backup Exec Operators don't understand the media managerment processes.

I agree the Partitions can cause Backup Failures but it is a toss up between:

-  Knowing that as long as a backup is sucessful then tapes that need off-site storage for a specific job will always be found in a small subset of slots


- Having your job fail because either you did not have enough slots in the patition or you got your media set protection wrong or you didn't insert a tape.

Without partitions, Backup Exec is designed to find an overwritable tape at all costs no matter what slot or what media set it is currently in. With partitions you can control this to force it to specific subsets of slots. The bigger your library the more likely you are to need some form of control like this. Also in the case of a datacenter hosting servers from multiple origanizations you might need this so you can guarantee that any one customer's data only ends up on one set of tapes and does not get mixed up (and possibly cause legal issues)

If we didn't give customers the choice between the two options then I suspect we would end up with a lot of enhancement requests/support cases for whichever option we did not provide.

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Hywel Mallett's picture

I agree entirely. Partitions may be useful for some, but don't think about using them until you've properly understood Backup Exec's media management, and then use them only to supplement the media management process where necessary, not to try and enforce your own.

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