Hi -
My DBAs has some serious concerns about running TDPO and I don't
know enough about it to be able to answer their concerns
authoritatively. Any information would be much appreciated.
The subject line was _NOT_ meant to denigrate them -- not at all
(they're clued in DBAs) but meant to get your attention, as I'm
sufficiently desperate. Sorry. :)
Setup:
- TDPO 5.4 (Solaris 10 Update 3 + patches)
- Oracle 10gR2 + patches
- TSM server 5.4 (AIX 5.2 TL 10 + patches)
- Plans to go to TDPO 5.5 + TSM server 5.5 shortly
Their concerns:
1) RMAN doesn't deal with non-transactional DB data loads well.
(i.e. data loaded not through the usual INSERT/UPDATE
methods, but done via sqlldr. This doesn't generate redo logs.)
True or false?
2) RMAN requires a recovery database be created to do recoveries to
(instead of recovering to original database/tablespaces in-place).
True or false? I thought RMAN didn't need an intermediate temp
database and could restore directly 'in-place'.
3) Will RMAN guarantee a good point-in-time view of DB data?
4) Same as #3 above, but what if the DB is currently processing
a large series of INSERTs or UPDATEs or sqlldr run, will RMAN
only send data that was present at the moment of backup start?
5) Does RMAN/TDPO use scale to really large DB setups? Say, tens
or hundreds of terabytes? Or even sub-10 TB?
Anybody using TDPO well with terabytes of Oracle data? (I
think they're hoping for assurances that it really does work
in the real world at that scale.)
6) How does Oracle RMAN know what rows to send for an
incremental backup? Does Oracle maintain a bitmap of some kind
or time-based logging of changed blocks or something? Any
pointers to whitepapers or information on how it works behind
the scenes?
They would prefer to utilize Veritas DB Edition (DBED)
checkpoint feature which is where a script runs to put all tablespaces
in backup mode, brings DB-based filesystems to a consistent state,
generate a checkpoint (snapshot-like) of the filesystem, then brings all
tablespaces back to online mode. The TSM BA client then mounts the most
recent checkpoint R/O then backs it up at the file level.
The problem with the above approach is this essentially results
in what amounts to a full backup every single time it kicks off. That's
just not practical in terms of tape cost as well as the length of
backups.
I see TDPO as the only practical choice for much faster and more
frequent backups (and restores) and is guaranteed for consistent
point-in-time views of DB data. The BA client was also not meant to back
up databases (though it *could* do so if properly quiescied).
My issue? I don't have enough meaty information yet to put
concerns to rest, and I'd really like to make use of TDPO after paying
out $16,000. Any info would be much welcome.
Thanks,
-Dan
