Oracle10g - Database Files on ODS2 or ODS5

[robert70]

Hello,

About to upgrade Oracle9i to Oracle10g on an Alpha running VMS8.3
The Question is this:-

Oracle upgrade notes makes it clear that the Oracle10g System files MUST reside on an ODS5 formatted disk.
However they say that the actual Oracle Data Files can reisde on either an ODS2 or ODS5 disk.
Is there any performance issues selecting either one over the other?

[Hoff]

Premature optimization? You're running Oracle. That's almost certainly going to be the juggernaut-class application here.

There are no salient differences in performance between ODS-2 and ODS-5, and the volume-level differences between the two are trivial, and the host I/O paths are basically the same for both.

The chief considerations include whether you can keep the stuff that expects ODS-2 operational. If you keep to an ODS-2 subset where that matters, that's usually feasible.

As for performance, you're running Oracle. You'll want to pick ODS-5 for its increased compatibility with newer tools, and you'll likely want to look at Oracle performance.

Though as Stonebraker commented an eon or two ago, all file systems stink as database platforms.

[robert70]

thanks Hoff
was thinking of changing our data disks to ODS5 for this upgrade and your answer would seem to back this up

I take it I can simply do a

$ set volume/struture_level=5 dkb100:
$ set volume/struture_level=5 dkb200:
$ set volume/struture_level=5 dkb300:

on the 3 volumes that are currently ODS2
just before I start the upgrade? Obviously after a backup!

[Hoff · Accepted solution]

I probably wouldn't do a specific extra backup here; not if I trusted my standard backups under normal circumstances.

The SET VOLUME /STRUCT=5 command does almost nothing.

At its core, the command changes a single constant within the storage control block; within an ODS-level data structure.

The "reversion" path is via BACKUP, and BACKUP can "downgrade" ODS-5 to ODS-2. That's a tougher nut, as BACKUP has to rename stuff.

[robert70]

All Understood Hoff
Seems nice and stright forward!
thank you very much

[robert70]

cheers