On-line vs Off-line Backups 
Author Message
 On-line vs Off-line Backups

I can't even believe I'm posting this, but I've exhausted all my arguments
for performing on-line backups over off-line backups specifically within a
24 x 7 x 365 operation. Namely,

On-Line Backups

Pro's

1. The database backup will be consistent at the point-in-time that it
started.  Modifications made to the database since the backup was started,
will not be included on the backup media.
2. The system is available 24x7.
3. It can be scheduled to run as required without any manual intervention or
supervision (assuming 1 tape will suffice)

Con's

1. Users may experience slightly slower response times due to hightened
disk/backup activity from that when both servers are solely servicing
requests.  This can be mitigated by scheduling the backup at the quietest
period.

Off-Line Backups

Pro's

1. No issues with users accessing the database.

Con's

2. No user access will be allowed while the database is off-line. The server
will not be available 24 hours/day.
3. Due to the complexity of the enterprise replication process this will be
a manual process requiring the attendance of trained personnel.
4. Potential for considerable synchronization issues with the DB
replication.
5. The off-line backups MUST be performed by Informix. If backups are
performed by NT, recovery via the backups will be to the point in time the
backup was taken rather than allowing roll-forward utilizing the transaction
logs within Informix.
6. If any problems are encountered during the backup (multiple tapes, bad
media, media failure etc.) the system would be down for an un-scheduled
length of time. With on-line backups, the issues could be resolved without
affecting service levels.

Can anyone think of any more ???

Thanks as always

S.



Wed, 18 Jun 1902 08:00:00 GMT
 On-line vs Off-line Backups

That about covers it.
Quote:

> I can't even believe I'm posting this, but I've exhausted all my arguments
> for performing on-line backups over off-line backups specifically within a
> 24 x 7 x 365 operation. Namely,

> On-Line Backups

> Pro's

> 1. The database backup will be consistent at the point-in-time that it
> started.  Modifications made to the database since the backup was started,
> will not be included on the backup media.
> 2. The system is available 24x7.
> 3. It can be scheduled to run as required without any manual intervention or
> supervision (assuming 1 tape will suffice)

> Con's

> 1. Users may experience slightly slower response times due to hightened
> disk/backup activity from that when both servers are solely servicing
> requests.  This can be mitigated by scheduling the backup at the quietest
> period.

> Off-Line Backups

> Pro's

> 1. No issues with users accessing the database.

> Con's

> 2. No user access will be allowed while the database is off-line. The server
> will not be available 24 hours/day.
> 3. Due to the complexity of the enterprise replication process this will be
> a manual process requiring the attendance of trained personnel.
> 4. Potential for considerable synchronization issues with the DB
> replication.
> 5. The off-line backups MUST be performed by Informix. If backups are
> performed by NT, recovery via the backups will be to the point in time the
> backup was taken rather than allowing roll-forward utilizing the transaction
> logs within Informix.
> 6. If any problems are encountered during the backup (multiple tapes, bad
> media, media failure etc.) the system would be down for an un-scheduled
> length of time. With on-line backups, the issues could be resolved without
> affecting service levels.

> Can anyone think of any more ???

> Thanks as always

> S.



Wed, 18 Jun 1902 08:00:00 GMT
 On-line vs Off-line Backups

Quote:

> That about covers it.


> > I can't even believe I'm posting this, but I've exhausted all my arguments
> > for performing on-line backups over off-line backups specifically within a
> > 24 x 7 x 365 operation. Namely,

> > On-Line Backups

> > Pro's

> > 1. The database backup will be consistent at the point-in-time that it
> > started.  Modifications made to the database since the backup was started,
> > will not be included on the backup media.
> > 2. The system is available 24x7.
> > 3. It can be scheduled to run as required without any manual intervention or
> > supervision (assuming 1 tape will suffice)

> > Con's

> > 1. Users may experience slightly slower response times due to hightened
> > disk/backup activity from that when both servers are solely servicing
> > requests.  This can be mitigated by scheduling the backup at the quietest
> > period.

> > Off-Line Backups

> > Pro's

> > 1. No issues with users accessing the database.

> > Con's

> > 2. No user access will be allowed while the database is off-line. The server
> > will not be available 24 hours/day.
> > 3. Due to the complexity of the enterprise replication process this will be
> > a manual process requiring the attendance of trained personnel.
> > 4. Potential for considerable synchronization issues with the DB
> > replication.
> > 5. The off-line backups MUST be performed by Informix. If backups are
> > performed by NT, recovery via the backups will be to the point in time the
> > backup was taken rather than allowing roll-forward utilizing the transaction
> > logs within Informix.
> > 6. If any problems are encountered during the backup (multiple tapes, bad
> > media, media failure etc.) the system would be down for an un-scheduled
> > length of time. With on-line backups, the issues could be resolved without
> > affecting service levels.

> > Can anyone think of any more ???

> > Thanks as always

> > S.

Pardon my lack of understanding here, but why would anyone want to do
off-line backups?  I see that my Oracle DBA has to go through and I
shudder.
--
John Carlson
Informix DBA
WHSmith USA

#include std_disclaimer.h     /* These are my opinions, not my company's
opinion  */



Wed, 18 Jun 1902 08:00:00 GMT
 On-line vs Off-line Backups

Quote:

> I can't even believe I'm posting this, but I've exhausted all my arguments
> for performing on-line backups over off-line backups specifically within a
> 24 x 7 x 365 operation. Namely,

> On-Line Backups

> Pro's

> 1. The database backup will be consistent at the point-in-time that it
> started.  Modifications made to the database since the backup was started,
> will not be included on the backup media.

1a. However, in conjunction with logical log backups, on-line backups will
provide identical restorability as that of off-line backups. (Maybe, you need
to stress this bit).

...

Rudy



Wed, 18 Jun 1902 08:00:00 GMT
 On-line vs Off-line Backups


Quote:
> I can't even believe I'm posting this, but I've exhausted all my arguments
> for performing on-line backups over off-line backups specifically within a
> 24 x 7 x 365 operation. Namely,

> On-Line Backups

> Pro's

> 1. The database backup will be consistent at the point-in-time that it
> started.  Modifications made to the database since the backup was started,
> will not be included on the backup media.
> 2. The system is available 24x7.
> 3. It can be scheduled to run as required without any manual intervention
or
> supervision (assuming 1 tape will suffice)

  The one tape restriction is not NECESSARILY there, if you are either:
  a) using ontape, have multiple drives and want to write tape drive
switching scripts
  or
 b) using OnBar with a storage manager that can access multiple tapes
(either with multiple drives or single drive with autochanger/library)

We are currently using solution (a) and are migrating to (b).  Only
production system is left to migrate.  Works, nicely.

Doug Agnew



Wed, 18 Jun 1902 08:00:00 GMT
 
 [ 5 post ] 

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