Re: What to keep in ASM?

On 2/26/07, Don Seiler <don_at_seiler.us> wrote:
> On 2/26/07, Alex Gorbachev <gorbyx_at_gmail.com> wrote:
> Does it make any sense to multiplex controlfiles/redo within the same
> disk group? We were only planning on one disk group, so that's
> another reason why I thought it might make sense to multiplex outside
> of ASM. Perhaps with striping it isn't an issue.

If it would be on filesystem - you might protect yourself from human mistake of removing one redo log. About a year ago I remember the case when DBA overwrote one copy of controlfile with small typo in tar command. On the other hand, you won't be protected from "rm -f *". You still can remove files from ASM but it's not that easy and it won't delete file that is in use.

In ASM - I don't see much sense to multiplex redo/controlfiles in the same disk group. You might put another controlfile into your FRA diskgroup, for example (you won't be able to unmount it then). I don't like to rely of FRA availability but every case is different. You do have disk mirroring somewhere anyway. Don't you? Mirroring on SAN or ASM or at least RAID-F in the worst case.

> > In this case I would doubt if you really need ASM at all but that's
> > another story. ;-)
>
> Mainly for the auto management of it. Obviously we've gotten this far
> without it, but I'd like to take advantages of some of the really nice
> features of 10g EE (ASM/ASSM/OMF) to save me a few keystrokes and
> headaches now and then.

ASM has nothing to do with ASSM. You can also use OMF with file system just fine.
Just list the feature that you think you will benefit from when using ASM. Then decide if it's worth the hassle of learning new technology and introduce one more component into your infrastructure. Note that I'm not against ASM -- we do have quite a few customers using it without real problems. Real problems in this case I mean corruptions. Not bad for something so new in Oracle. ;-)

> > As I mentioned, if you have dedicated DG for backup only (not FRA
> > location) than you should be able to unmount it and temporary mount on
> > your development machines subject to SA policies.
>
> Gotcha. Makes a lot more sense than the first time I read it!

Cool. Back to my English course then... ;-)

-- 
Best regards,
Alex Gorbachev

http://www.oracloid.com
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