fbackup and Oracle databases

[Bernard Igoe]

Hi there,

We are quite new to HP-UX, so forgive my ignorance if this has been asked before.
We are running Oracle on HP-UX 11
We currently use fbackup to back the data areas up after putting the database into backup mode. When fbackup hits a data area that is currently being modified, we get a warning saying that the file was not successfully backed up. Is there any 'tweaks; to fbackup when trying to backup an Oracle instance in this manner

Thanks in advance
Bernie

[Volker Borowski]

Hi,

I have to admit, I never tried this with fbackup. With tar it works fine.
So the question is: is the data on the tape ?
If yes, I would assume it is ok (And as far as I remember it is just a warning and the file is on the tape).

Anyway, the best way would be to test the restore (on a diffrent box)! Do a dbverify and a full export after the recovery. If this goes ok, fbackup is just cautious because it does not know BEGIN BACKUP / END BACKUP.
You should verify your restore procedure in any case.

Volker

[James R. Ferguson]

Hi Bernard:

When 'fbackup' begins backing up a file (any file) it "notes" the file's modification timestamp. Once the file has been fully transferred to tape, a comparison is made to determine if the timestamp has in fact changed. If it has, then the file (on tape) is marked as "bad" and the copy attempted again.

'fbackup' will retry ' maxretries' times before skipping the file. The 'maxretries' value is defined in the 'config' file (see "man 1M fbackup"). The default is five (5). Each retry will be logged. Redirecting the 'v'erbose dialog of 'fbackup' to a file is a great way of seeing this and other messages.

The key consideration for databases, is to have an absolutely quiet, consistent relationsship among all files during the period in which a backup is occuring.

...JRF...

[Magdi KAMAL]

Hi Bernard,

This is a warrning that the file is open but oracle take the control on the db files to have a coherent files for backup.

Go ahead you have a valid backup.

Magdi

[Wodisch]

Hello Bernie,

first, do you run that backups "offline" (when Oracle is
actually shut donw) or "online" (while Oracle is up and
running and still modifies the files)?
You simply MUST instruct Oracle that you intent to do
an online backup by issuing commands like
alter tablespace XXX begin backup;
from "svrmgrl" or "sqlplus" as dba, then use your backup
tool, and then tell Oracle, when it is over with
alter tablespace XXX end backup;
And that you have to repeat for each and every
tablespace you have (replace the "XXX" in the examples
above with their names).

Only then you do backup, else you do "tape-tests"
and you have no guarantee that you will be able to
restore from those backups and restart Oracle!

HTH,
Wodisch

[James R. Ferguson]

Hi Wodisch:

"tape tests" -- very well put, Indeeed, trying to copy files with 'fbackup' that are actively changing is a great way to run down the tape and find that you can't restore a damn thing.

Glad to see you posting again with regularity.

Regards!

...JRF...

[Jeanine Kone]

It sounds like you are attempting to do a hot backup. The method for putting the tablespace in backup mode has already been mentioned. I will just note that if you are truly in backup mode then the file should not be active. Oracle will not write to the file while in backup mode (the redo logs are used instead). If you are getting messages that the file has been modified or is in use, I would be very doubtful that your backpup is a good one.

[Bernard Igoe]

All,

Thanks for the prompt responses, when i figure out how to score the responses, I will. I would like to add that the Oracle tablespaces are put into warm backuo mode via the use of the ALTER TABLESPACE xxx BEGIN BACKUP

Rgds

Bernie

[Simeon Fox]

When an oracle tablespace is in backup mode the associated datafile headers are frozen. Changes to the data still cause the files to be updated and the unix timestamp to change - I have tested this. However, because the file headers were frozen, during recovery this "fuzzy" data is ignored and changes are applied consistently from the oracle redo logs. At least this is my understanding!
You must use "tar" to backup online datafiles since fbackup may reject them for the reasons stated above. Hope this clarifies.

[Roman Dijanosic]

If I would be Bernard Igoe I would give Simeon Fox
10 (hey maybe 9 and give me 10) points.

All others more or less they are wrong in their saying.
Disregard them (sorry J.R. Fegusson... but you can't have
everything right).

This kind of "error" that you get is very tricky to
understand. "Symptom" is "in" UNIX, hey but the reason
why this happen is in Oracle. And it is even one of the
things that it is widely not well "understood"...

All in this link (hope you read it to the end)...

http://www.speakeasy.org/~jwilton/hot-backup.html

Roman D.