Forward Incremental to tape

[jfnk1ng]

We have a daily backup job, using Forward Incremental to create a synthetic full each Saturday. We have just set up an associated tape job that runs afterwards to copy the resulting data to tape for offsite.

What we are seeing is that the tape only contains that day's .vib file, which will make restoring a bit of a nightmare. What we would like is for the tape backup to include the current chain (that is the most recent vbk and the subsequent vibs), or just to have a synthetic vbk each day.

The synthetic vbk only seems to be an option if we use forever forward on the backup job, but we want to stick with forward incremental as it gives us a quicker restore from disk. We also considered reverse incremental, but are put off by various blog reports that it would increase the daily backups by 3-4 times.

So, is there any way to keep Forward Incremental but have the chain, or a full backup, go to tape rather than just the .vib?

Thanks

[Dima P.]

Hello Jeremy.

So, is there any way to keep Forward Incremental but have the chain, or a full backup, go to tape rather than just the .vib?

Yes, you can uncheck the incremental backup option in tape job properties and backup only fulls (synthesized fulls for the configured days) to tape.

[jfnk1ng]

Thanks Dmitry

I made that change for last night's backup, but result was that nothing was backed up at all. The job said "No new files to backup per job settings". I guess it must be looking for a full backup, but it couldn't see one. I checked the incremental backup option and ran again, and it backed up the .vib file as before. Is there anything else I should do to get a full backup each day?

In the Full Backup settings I have all weekdays selected for "Specify virtual full backup schedule", but I note this is for "source backup jobs which use a backup mode without periodic full backups". Our source backup job is running Forward Incremental, as per my mail above, so I suspect this setting is ignored (since the Fwd Incremental performs a weekly synthetic full)

Thanks
Jeremy

[veremin]

Basically, you have two options:

* switch to reversed incremental mode and let backup to tape job archive the latest restore point (.vbk) daily
* switch to forward forever incremental mode by disabling periodic synthetic full backup and let backup to tape job synthesize virtual full backup on tapes daily

Thanks.

[jfnk1ng]

Thanks Vladimir

Confirms what I thought/feared/expected. I'll do a bit more testing around Reverse Incremental, to see how badly it affects the backup duration, and then go for one of those two methods

Jeremy

[veremin]

If you're concerned with additional I/O requirements that reversed incremental mode brings, you can switch to forward forever incremental mode instead. It should be less stressful for your target repository.

Absence of periodic full backup (as is in case of forward forever incremental mode) should not bother you, as long as you run periodic health checks along with SureBackup job.

Thanks.

[jfnk1ng]

Thanks. My concern with forever forward is the restore time. At the moment the daily incremental backup takes about and hour on average. If we have say 30 retention points then wouldn't restoring back to last night require that the original full backup and all subsequent incrementals are processed? That would take quite a while wouldn't it?

Obviously the 1 hour is for the entire VM estate and we would likely only be restoring a single server (unless somethings' gone really wrong!), so maybe the time would be less - or would it? I'm not sure how the maths of this works.

Thanks
Jeremy

[Dima P.]

If we have say 30 retention points then wouldn't restoring back to last night require that the original full backup and all subsequent incrementals are processed? That would take quite a while wouldn't it?

With VM restore from tape you have two options. One is to perform staged restore to temporary repository (so called staged restore option). Another option is to perform direct VM restore from tape (without staging the backup in the repository). Both of these restore option will require to sequential read the blocks from tape media, so if you have long incremental chain on tape that may take more time than restoring from a full backup.