AI in Progress 8.3D

[rudra132001]

Hi ,

We need to enable AI on Progress 8.3D database . I have two queries in this regard -

i. The prod databases are shutdown every night for tape backups . Do we need to enable AI after the databases are started up ? Or is it an one time activity

ii. Since the databases are shutdown and started every night , will the AI switch happen automatically at that time .. if so do we need to go for manual switching ?

We have 6 fixed and 1 variable AI extents defined in structure files .

 

[TomBascom]

8.3 is ancient, obsolete and unsupported. So it is a very, very good thing that you are enabling after-imaging.

Enabling AI is a one-time event. Shutting down will switch extents.

In later versions of Progress it is simpler to configure all AI extents as variable because it makes it very easy to switch extents on a schedule without wasting lots of disk space or having lots of etxents. I forget exactly when that feature became feasible but if 8.3 supports it you might want to consider it.

Obviously 8.3 is dramatically overdue for an upgrade.

 

[Casper]

1. No you just activate it once, and it will be activatd until you deactivate it explicitly.
2. Depends on how you take the backup, if you use probkup then the switch is done by probkup. If you use an external tool (like copy ) then you need to manual switch the extents.
   You could try, however, to make your backup plan more reliable and switch and archive AI extents more periodically, you have to script that though.
3. Upgrade!!!

I suppose V8 doesn't have an online backup?

Casper.

 

[Casper]

Shutting down will switch extents.

Is that a version 8 thingy?

Casper.

 

[TomBascom]

Uh, no, that was me having a brain cramp and reading "shutdown" as "probkup".

 

[TomBascom]

One thing to keep in mind regarding the "one time" nature of enabling after-imaging... that is true but when you do a restore from probkup the restored database does NOT remember that after-imaging was enabled. You must re-enable it (after rolling forward).

 

[TomBascom]

As I recall online probkup goes back quite a ways. Maybe even to v6?

 

[rudra132001]

Hi Tom / Casper ,

Thanks for the detailed explanations..that was very helpful ..

I had one more query regarding the backup policy of the database before we enable AI .. I searched in KB and understood that we need to take a full backup of the database before enabling AI .. my question is - do we need to take an offline backup / or will an online backup of the database serve the purpose .

 

[TomBascom]

With OE10 you can do an online backup and online enable ai all in one step.

With version 8 you will need to shutdown.

 

[rudra132001]

Hi Tom ,

I got lil confused here ... we have scheduled online db backups for 8.3D databases in the server and the process has been running fine , we are able to get db backup files .. do we still need to go for an offline backup or will taking an online backup suffice ?

 

[TomBascom]

With v8 you will need an offline backup.

 

[rudra132001]

Thanks Tom ..

Kindly advice on the AI extents .. we plan to have 6 fixed extents and for the moment we are relying on the daily offline backup for the extent switch ..the offline backup is scheduled daily in cron on the server.. we plan to have a script for manual switching but not considering it as of now ..

 

[TomBascom]

I'm not sure if there is a question in that last post?

 

[rudra132001]

Sorry for the confusion .. wanted to check whether can we relay on the probkp backup policy (online/offline) for ai extent switch ?

Also does taking a probkp (online/offline) takes the backup of ai files ?

 

[TomBascom]

Yes. Either form of probkup will switch extents.

No. Probkup does not backup ai files -- that would be pointlessly redundant. Everything in the ai files is already in the backup and they cannot be used with that backup for a roll-forward. (They could possibly be used to roll forward with the previous backup but there is no guarantee that that is the complete set that you would need...)

It is possible that you are slightly confused about how ai works. The 6 extents that you have defined need to be monitored and managed between backups. As they fill up (or on a schedule) the full extents need to be copied to a safe location (preferably a remote location that is in another time-zone). Once a full extent has been saved it can be marked empty and reused. If, for instance, you switch extents every hour each of your 6 extents will be reused 4 times a day. Only the last iteration would be contained in the probkup which wouldn't be of any use at all.

To make your life easy rename the extents as you switch them. Use the sequence# to label them. i.e. cp /ai/dbname.a1 /aisave/dbname.00001; scp /aisave/dbname.00001 farwayserver.

 

[ron]

Let me add my penny's-worth ...

Tom has pointed out that Progress 8.3D is unsupported. Progress has come a long way since 8.3D. PLEASE don't dismiss this issue - it really IS IMPORTANT! You really, really should advance - if not to 10.xx, then at least to 9.1E - which is (just) still supported.

Moving to 9.1E (or later) not only allows you to have Storage Areas (that allow you to have a tidier and more efficient storage environment) - but you gain a function not available in 8.3D - the ability to use " [FONT=&quot]rfutil -C aimage extract[/FONT]" which was introduced in one of the 9.1D minor releases. This allows you to not waste a lot of disc space storing-away your AI files.

You don't have to do an offline backup before starting AI - although the documentation tends to imply that you do. You can start-up the brokers - then execute "mark backed up" - then start AI - then start an online probkup.

The result will be that AI extent xxx.a1 will be "full" - but useless. Just set it to "empty". Extent xxx.a2 will hold all AI notes written after the moment when the probkup started - and in the event of a recovery it is the first extent to be rolled-forward.

Is this a good idea? It depends on your circumstances. You have to understand that if the backup fails for any reason - you don't have a recovery point at all, and all your AI files are useless. So, think about it. If your system is "very quiet" while you are taking the backup then perhaps the risk is small enough to be acceptable. But if your system is "busy" you need to think about it. Note that a backup to disc is less likely to fail and should be faster than a backup to tape.

I wholeheartedly agree with the advice from others that you *MUST* use AI - but you also must go to some trouble to experiment with it and make sure you understand how it all works. If you don't understand it WELL, you are not in a good position to manage AI and be able to properly deal with a recovery.

Ron.