Question about Backup Image fragments (One backup id split up in to parts)

[RLeon]

Hi all,

I understand that a backup image (identified by its backup id) could be fragmented and stored on different tapes.
Given the following scenario with two tapes (media ids AB0010 and AB0011) that each contains some backup images:

AB0010:
abc_1025079522
abc_1025079523 (fragment 1)

AB0011:
abc_1025079523 (fragment 2)
abc_1025079523 (fragment 3)
abc_1025079524

The above shows that the image abc_1025079523 is splitted in to 3 fragments.

Now my question is, if I expire everything on AB0010 by using:
bpexpdate -m AB0010 -d 0
(Note: I know that the tape could still be imported to retreive data, but for this thread, let's just focus on the catalog level.)

What happens to abc_1025079523 as a whole?
Will bpexpdate:
1. Skip fragment 1 so that abc_1025079523 survives as a whole, but leaving AB0010 not fully emptied. (fragment 1 still lives in it)
2. Expire all fragments of abc_1025079523, including those on AB0011. The whole abc_1025079523 is gone, but this action "affected" AB0011. (Poor AB0011 was so unlucky :( )
3. Expire just fragment 1 of abc_1025079523. (I don't even know if this is possible, and if so, can files associated with abc_1025079523 be restored with only fragments 2 and 3?)

Thanks!

RLeon

[RLeon]

I guess I have a similar question about importing tapes with fragmented images.

Using the previous example, what would happen if I import the AB0011 tape to a different Netbackup master server?

Will it:

1. Import all 3 abc_1025079523 (fragment 2), abc_1025079523 (fragment 3) and abc_1025079524

2. Import just abc_1025079524

If Netbackup can imports all 3, including the 2 fragments of abc_1025079523, what should I expect to see in the BAR restore interface? For the host abc, will I only see the files associated with fragments 2 and 3 of abc_1025079523? (In other words, I would not see files associated with fragment 1 of abc_1025079523)

Thanks,

RLeon

[mph999]

1. It will only expire what is on the specified mediaid ....

Regarding the import ...

AB0010:
abc_1025079522
abc_1025079523 (fragment 1)

AB0011:
abc_1025079523 (fragment 2)
abc_1025079523 (fragment 3)
abc_1025079524

If you import AB0011

The phase one import job will 'partly' build the header files for both backup ids on the tape.

The phase 2two import job will only complete for image abc_1025079524, it will error with regard to non-consecutive or missing fragments for image abc_1025079523 

Martin

[Mark_Solutions]

I believe that if you expire a tape it expires all images on that tape and removes them from the catalog

As a result the fragment of the image on the other tape will also be expired

So if you expire AB0010 all you will have left is abc_1025079524 on AB0011.

In relation to the imports you need to run a Phase 1 on both tapes to be able to run the Phase 2 for all images as without fragment 1 of an image it will not present that image as being even available for the Phase 2.

So if you just import AB0011 then you will only see abc_1025079524 available to import

[RLeon]

To Martin,

Thanks for your reply.

Can you please elaborate on both answers?

For bpexpdate, if it only expires what is on the specified media id, then wouldn't that mean fragments 2 and 3 are left without their brother? (fragment 1), what does that mean then, in terms of restoring files associated with abc_1025079523 as a whole?

For the import part, it makes sense that an error would show up (because fragment 1 is missing), but wouldn't it make more sense for Netbackup to ask me nicely to insert the media that contains fragment 1, so that it could continue the import of the image? Also, base on your answer, what happens in terms of restoring things from abc_1025079524 as a whole? Will only fragments 2 and 3 of it show up in BAR, or am I totally off with this.

Thanks,

RLeon

[Mark_Solutions]

RLeon

please see my answer above - I believe all of the image would expire (from both tapes) and NetBackup would not give you the option to run the Phase 2 if it did not have all fragments so there should be no failure

[RLeon]

Hi Mark,

Thank you for your input, again!

For the bpexpdate AB0010 question, I understand now that AB0011 will be affected, because a fragment of an image cannot exist alone.

As for importing, am I correct in saying that the only way to fully import abc_1025079523 is to follow the below steps in strict order:
1. Do phase 1 import AB0010 (contains fragment 1 of abc_1025079523)
2. Do phase 1 import AB0011 (contains fragment 2 and 3 of abc_1025079523)
3. Do phase 2 import AB0010 (abc_1025079523 now visible)
4. Do phase 2 import AB0011

If I am correct in the step order, then wouldn't I get some errors in step 3, like "Waiting for fragments 2 and 3 of abc_1025079523"?

RLeon

[Mark_Solutions · Accepted solution]

You are almost there!

1. and 2. are correct.

Phase 2 however is done based on image and not tape media ID

The only images you will see in the catalog import section are the complete ones - or just the one in this case so there will never be a Phase 2 for the other image so there will be nothing to fail

If you did have a fragemnt 1 for an image but no fragment 2 then you may get an error when searching for images to import in the catalog section

[RLeon]

Hm....

So I should first do a phase 1 import for all the tapes I want to import, then after that, I will be able to see a list of eligible images for phase 2 import. (Ineligible images would be those that still don't have all the fragments after I finished phase 1 of all the tapes, and these will be unavailable for import.)

Next, I could just select all the eligible (available) images for phase 2 import, and Netbackup would mount the tapes to drives for reading as it sees fit. E.g., When it needs fragment 2 and 3, it will simple mount the tape that contains them, automatically.

Hope I'm getting it.

Thanks,

RLeon

[mph999]

Hmm, I stand corrected on the question regarding bpexpdate - thanks Mark ...

It is possible to get an error on phase two with missing fragments (that is, not all tapes phase 1 imported). It may be that NBU is smart enough to realise the first fragment is missing, but certainly, if for example, the last few fragments are missing, you will only find out during the phase 2 import.

http://www.symantec.com/docs/TECH163163

eg

Import Phase 1 was a success

But when trying to import an image on Phase 2 the following Messages occur;

INF - Skipping backup id client_1303540857, there is no fragment 1.

INF - Found no images matching the selection criteria that were ready for phase 2 import.

Notice; in this case the Backup-id is client_1303540857

So it will advise about fragment 1, but only during the phase 2.

Martin

[Mark_Solutions]

RLeon - that is correct in your final summary, and as Martin has confirmed if the Phase 1 finds fragment 1  but not all of the fragments for a Phase 2 then you will indeed get a warning about it

The log (results tab) of the Phase 1 will tell you exactly what has been found on each tape

Hope we have helped

[RLeon]

Thank you both for your speedy help. I didn't think I could close the thread this quickly!

Thanks Martin, for the link to the technote, it sums up the topic of this thread quite nicely and it would be a good referece for me.

I flag Mark's post the solution because it was the first post that striked me in my head with the clear picture.

Onces again, thank you both!

RLeon

[mph999]

Super, we got there in the end .... with a minor hiccup on the way ...

This is an excellent technote for the actual process.

http://www.symantec.com/docs/TECH72429

Although it mentions 6.x, it is valid for 7.x

NOTE.  The process of importing BackupExec tapes is different, and there limitations on the images once imported (just incase you are thinging along these lines ...)

Martin

[rizwan84tx]

This is a good post RLeon. Thanks Mark and Martin on detailing the Import process.