Conceptionsl information about media pools?

[TommyB]

Hi,

i have been reading the online help about media pools back and forth, but did not find any conceptual information about media pools such as:

- Do I have to use multiple media pools? What would be the advantages?
- How are media pools and media sets related?
- When should I use the "create new media set" switch?
- What are common use cases?

So I'm not looking for "How do I use those features" but rather "What was the rationale of the Veeam developers when adding those features"

thanks
Thomas

[Dima P.]

Hello Thomas,

- Do I have to use multiple media pools? What would be the advantages?

There are two types of media pools: predefined and logical.

Predefined is service pool, used by Veeam B&R to sort media in the library. Here is the list: Free, Unrecognized, Imported, Retired - for the detailed explanation of each pool please refer to the user guide (p.426)

Custom pools are created by user and they are actual target of backup to tape/file to tape job. You can have one media pool for all you backup to tape/file to tape jobs - or create separate media pools. This just provides scalability and granularity of tape job set up, as for example for each media pool you specify different retentions. Also it works perfectly for recognizing media in case of offsite exports.

- How are media pools and media sets related?
- When should I use the "create new media set" switch?

Media set in fact is a bunch of tapes taken from the specified media pool for backup to tape job/file to tape job. If the media pool is the whole storage - media set is a small portion of this storage that should be taken to proceed backup to tape operation. Then you could continue to use this set if any free place left, create a new one - that’s why we provide these options for media set creation, plus scheduled creation of media set which is perfect when tape backups are exported offsite on specific days and you need to create a new media set right after export.

If create a new media set for every backup session option is selected, a new media set will be created for each new backup session. Each backup session will write its backup set starting with a new tape. It fits perfectly when you transfer tape backups offsite right after backup to tape is done.

- What are common use cases?

Backup to tape mostly used to store data offsite. Some users do that on specific days, others may transfer tape with backup as soon as the job is completed - it always up to the user.

Another option with standalone drives to create backup to tape and continuously backup 1-2 important server without exporting tape.

However, do not forget about (3-2-1 rule) - that’s another reason to use backup to tape functionality.

[TommyB]

Hi,

Thanks for the explanations - everything makes more sense now

I'm quite new to virtualized environments and Veeam backup, so I'm trying to find my way from classic backup schemes i used before to something more useful.

In my old conventional infrastructure with physical servers I used to have 10 tapes, Week1.1 - Week1.5 and Week2.1 - Week2.5 plus 12 archive tapes each year.

But now, since the full backup does no longer fit on a single tape (LTO4 800 gb net) I have to re-think my tape backup strategy.

Thomas

[Dima P.]

Thank you!
Your current scenario could be easily set up with Veeam tapes functionality:

For the yearly archiving tapes :
- Set up a job that would create full backups of the important servers once a year (this could be done via scheduling or you could run this job manually once a year)
- Create a Media pool named Yearly Archive, and assign appropriate number of tapes
- Use "Create new backup set for new backup session" media pool option (not necessary, but I would do so)
- Use "Never overwrite data" as retention option
- Set up backup to tape job with "Export when job is completed" option

So when the backup to tape is complete you can take this media offsite or move it to your vault.

For weekly backup to tape :
- Set up a job that would create a backup for the necessary servers. Please note that backup to tape job processes only VBK (full backups) and VIB files (forward increments). Reversed increments (VRB) are skipped form processing. So if you are interested in having multiple restore points you need to set up backup job as Incremental backup
- Create a Media pool named Weekly Backup, and assign appropriate number of tapes
- Use "Do not create, continue using the current media set" media pool option (not necessary, but I would do so).Each subsequent backup session will write its backup set to the existing media set: it will append backup content to the content that was written to tape with a previous backup session. If, however, a backup set is started with a new tape, Veeam B&R will create a new media set for it.
- Use "Protect data for (time interval - possibly 1 week/month)" as retention option

Please note that i would advise to test it in order to see how it scales your production first and then run on a scheduled basis - as each customer has unique infrastructure and some problems/questions may arise.
Cheers!

[TommyB]

Thank you!
For the yearly archiving tapes :
- Set up a job that would create full backups of the important servers once a year (this could be done via scheduling or you could run this job manually once a year)
- Create a Media pool named Yearly Archive, and assign appropriate number of tapes

If I use a schedule, what happens if a tape from a different media pool is in the drive at the time when the backup starts?

If, however, a backup set is started with a new tape, Veeam B&R will create a new media set for it.

"new tape"... does this mean "from free pool"? or "empty tape"?.

[Dima P.]

if a tape from a different media pool is in the drive at the time when the backup starts?

It should be automatically moved to slot in case it is not locked by another job. If it does - the archive job would wait until the running job ends and place the tape from its own media pool. As you can see it is another big plus of using separate media pools for different type of jobs/schedules.

does this mean "from free pool"? or "empty tape"?

Best explanation I ever seen:

When the tape is full and there are other tapes available in the pool, data will be written to them until there are no available tapes in the pool. Then either the oldest tape in the pool will be overwritten or a new tape from the free poll selected (depending on the data protection settings).

[TommyB]

Thanks, this helps a lot.

But you always seem to assume a tape library is used... but I'm using a single, stand-alone HP tape drive.