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Backing up dedupe store to tape library: Store is larger than online tape library

Gordon_Fecyk
Level 3

I want to do a disaster recovery backup of my deduplication store. I've done this before when my dedupe store was small enough to back up to tapes in the robotic library, but now the store has grown well beyond the size of the library.

What I want to know is if I can change tapes in the library during the backup operation, or rather, when the server complains that it is out of online tape space. The tape library is not normally locked in software, so I can change tapes while BE is running. What I'd expect is that the backup would be in progress, I'd run out of tape room and get a suitable alert, then I'd swap tapes and do an inventory. Once the inventory is complete, I'd hope the server would see fresh tapes in the library and resume the backup.

The dedupe store volume is just under 20 TB total including free space, and I have a separate 1.5 TB volume configured for VSS to use. The tape library has a max online capacity of 9.7 TB so I'd have to swap tapes once. I'd probably have to swap the first set of tapes back for verification, or just forego verification.

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2 ACCEPTED SOLUTIONS

Accepted Solutions

CraigV
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Hi,

 

1. I hope you're duplicating the dedupe folder to tape, and not backing it up directly? Backing it up directly would see the folder unrestorable.

2. You can configure an import slot. When BE requires more tapes, it's going to prompt you to import more tapes. You can then export used tapes, and import the new set, during which BE will validate whether or not the tape is useable. If it is, the job will continue.

Check the BE 2014 Admin Guide to see how to do this, but it is pretty straight-forward.

Thanks!

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Larry_Fine
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So going back to the problem of backing up something larger than my library's online capacity... my library has eight slots, seven of which normally have tapes and one as a cleaning tape. BE will ask me to add more tapes at some point. Craig V explains that I'd need to export (I'd select "Import after Export") all of my data slots when they're full, at which point BE will prompt me to insert more tapes. I'd then change the tapes, click OK, then inventory them (the tapes don't have bar codes). Once BE sees fresh tapes it would resume my backup.

All correct, except I do not believe that you will need to run the inventory job.  As soon as the backup jobs sees that there is different media in the library (via the iexport/import process), it will check to see if any of the freshly imported tapes are usable to continue the backup.

I hope that sounds correct. I've not had to use export / import before because I've never had to back up something larger than 9 TB at once. Usually I'd just change tapes and re-inventory all slots.

Correct.  When you are doing a "voluntary" export/import, then it is best to do an inventory of a tape without a bar code so that you and BE are in agreement with what is in the library.  But when BE is "media starved", BE becomes more agressive and starts checking unknown media.

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9 REPLIES 9

CraigV
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Hi,

 

1. I hope you're duplicating the dedupe folder to tape, and not backing it up directly? Backing it up directly would see the folder unrestorable.

2. You can configure an import slot. When BE requires more tapes, it's going to prompt you to import more tapes. You can then export used tapes, and import the new set, during which BE will validate whether or not the tape is useable. If it is, the job will continue.

Check the BE 2014 Admin Guide to see how to do this, but it is pretty straight-forward.

Thanks!

Colin_Weaver
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Employee Accredited Certified

I think CraigVs first point relates to that fact that you should not just backup the drive letter of the Dedupllication Storage folder, however you can backup the Deduplication Store via Shadow Copy Components (SCC), however as you say it can grow to be very large.  In theory you can therefore use CraigVs second point which is just have it span across multiple tapes (easiest done with a library)

 

However even though we provide a method to write the deduplication store to tape via SCC, it is not the recommended backup method as the recommended method is to duplicate the backup sets owned by the deduplication store to tape.

Main Pros of duplicating backups sets to tape and not backing up the deduplication store via SCC:

- In the event of a disaster affecting all the servers in the server room, you don't have to get the  deduplication data back and operational before you can start recovering your production servers. Yes you do have to get your Backup Exec Server operational with inventory and catalogs, but once you have done that you can restore from the duplicated sets on tape directly back to production hardware and not have to restore the deduplication data and run furthr inventory (and possiby catalig) operations

- smaller individual sets spread across multiple tapes, meaning if a tape is lost, corrupted or damaged you will still be able to recover from other tapes and get back a large amount of your data. If you lose a tape from a spanned set of a Deduplication Storage folder SCC backup you will NOT be able to recover anything in the Deduplication  Storage folder

- no single job that takes hours to run, so more control over when your tape devcecs are being used. Once the SCC backup of the Deduplication Store starts it will have to remain running until complete, which for a big store could be a long time window

- you only duplicate recent backups and not all your backups in one go like an SCC job against the deduplication Storage folder performs.

 

Main cons of duplicating backups sets to tape and not backing up the deduplication store via SCC:

- duplicate sets are rehydrated so more tape capacity (number of individual tapes) needed

- duplicate sets may be slower than writing the same data directy to tape, because of the rehydration process. (Although the daily time window should still be less than the SCC backup as you only duplicate the recent sets)

- possibly more complicated job setup as may have to have a better understanding of  append and overwrite settings

- if you have lost your deduplication storage folder than any sets from before this loss will have to be restored from tape, which when compared with having the same backup set in deduplication is a slightly slower process (of course you could duplicate the tape based sets back into the deduplication store)

- if you have lost your deduplication storage folder, then either the next backup jobs to a new empty one will have poor deduplication ratios or you will have to seed the data back into the empty folder by duplication back from tape. 

Gordon_Fecyk
Level 3

I didn't mean to scare you with my description... I do dedupe backups using the shadow copy selection per the instructions for disaster recovery of a dedupe store, and I don't try to directly back up the volume the store resides on.

The question was just about backing up something larger than my tape library's online capacity, and it happened to be my dedupe store. As for the length of time, that's why I have a separate volume for shadow copies. I fully anticipate this to take days, but with VSS and the separate volume I hope to continue using the store during that time.

So going back to the problem of backing up something larger than my library's online capacity... my library has eight slots, seven of which normally have tapes and one as a cleaning tape. BE will ask me to add more tapes at some point. Craig V explains that I'd need to export (I'd select "Import after Export") all of my data slots when they're full, at which point BE will prompt me to insert more tapes. I'd then change the tapes, click OK, then inventory them (the tapes don't have bar codes). Once BE sees fresh tapes it would resume my backup.

I hope that sounds correct. I've not had to use export / import before because I've never had to back up something larger than 9 TB at once. Usually I'd just change tapes and re-inventory all slots.

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CraigV
Moderator
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Hi Gordon,


that's essentially how it will work. In my opinion, I never used a dedicated cleaning slot and preferred BE to tell me when a cleaning tape was required. It freed up that extra slot for a backup tape.

Your only other option is to rip and replace the tape drive for something bigger.

Thanks!

 

Larry_Fine
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So going back to the problem of backing up something larger than my library's online capacity... my library has eight slots, seven of which normally have tapes and one as a cleaning tape. BE will ask me to add more tapes at some point. Craig V explains that I'd need to export (I'd select "Import after Export") all of my data slots when they're full, at which point BE will prompt me to insert more tapes. I'd then change the tapes, click OK, then inventory them (the tapes don't have bar codes). Once BE sees fresh tapes it would resume my backup.

All correct, except I do not believe that you will need to run the inventory job.  As soon as the backup jobs sees that there is different media in the library (via the iexport/import process), it will check to see if any of the freshly imported tapes are usable to continue the backup.

I hope that sounds correct. I've not had to use export / import before because I've never had to back up something larger than 9 TB at once. Usually I'd just change tapes and re-inventory all slots.

Correct.  When you are doing a "voluntary" export/import, then it is best to do an inventory of a tape without a bar code so that you and BE are in agreement with what is in the library.  But when BE is "media starved", BE becomes more agressive and starts checking unknown media.

Gordon_Fecyk
Level 3

I thought I'd post an update. Seeing as I haven't done this before and haven't seen a similar question asked, I figured an update would help others.

The export / import behavior is the correct one. When the library became full, I swapped all tapes in the library and did an "Import after export" on all library slots. I thought I'd need to do an inventory before the backup would resume, but the tape device was already in use by the time I got the chance to issue an inventory command. It turned out BE read the "<unknown media>" before attempting to write to it and determined its media label, rather than try to make new media, kind of inventorying the tape first before using it. This must be the 'agressive' behavior Larry Fine described.

This is good. I can do a backup of this monster without needing to buy an additional robotic library. Thanks for the help here.

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CraigV
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...so, is it solved now?

Thanks!

Gordon_Fecyk
Level 3

Is there a way I can credit two people with a solution? I see the "Request split solution" option and I did that, so if you two don't get credit from the site, at least accept thanks for the help.

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CraigV
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That's exactly the selection to make when you want more than 1 person to get the credit. Not sure when/if the admins on the site will approve, but that is the correct option to take!

Thanks!