Re: Q:To ASM or Not to ASM
- From: Niall Litchfield <niall.litchfield@xxxxxxxxx>
- To: AmihayG@xxxxxxxxx
- Date: Wed, 13 Jul 2005 09:46:16 +0100
in line
On 7/12/05, Amihay Gonen <AmihayG@xxxxxxxxx> wrote:
>
> I've some questions on ASM (automatic storage management )
> I've read a lot of materials on this issue , I think ASM is a good
> concept in simplify the installation & maintenance of oracle database.
> I work in R&D in my organization , and we need to decided if to cooperate
> ASM instead of some other LVM.
> I build a small list of advantanges and disadvantages on ASM , and some
> questions . I would like to hear you comments .
> Advantanges:
> 1. Simply configuration and maintenance. (same layout ,with regard to O/S
> type . The only change is the numbers of disk per disk group)
>
Is this different from a competitor LVM?
2. Reduce extra level of LVM (reduce price , same vendor in all the stack
> ).
> 3. Performance (raw device access , striping in extent level )
>
I haven't seen any information that suggests ASM performs any better than
Veritas or any other LVM?
disadvantages:
> 1. New technology . Not wide speared , most IT doesn't have enough
> knowledge in this area.
>
I'd tend to agree
2. Backup & recovery must be done using RMAN .
>
Isn't that an advantage?
3. Single point of failure - If ASM instance is down ( , I'm not sure about
> this point).
>
Correct.
4. You can only keep certain classes of files on ASM so you may well need a
second LVM for all your other data storage anyway.
My questions are :
> 1. Do you think that ASM will be acceptable next year as LVM solution for
> oracle database in big companies ?
>
Yes, though probably large companies will avoid it and run with some other,
existing clusterware lvm software etc.
2. Do you think that ASM can be fine tuned as you can tune in a file base
> level installation ?
>
One of the main selling points is that you forget about tuning the IO
yourself altogether. So no it can't be fine tuned so well. For most people I
rather suspect this is an advantage as well. if you can't tune it you won't
go looking for that extra 2% performance at the cost of an extra 3 days
downtime a year.
--
Niall Litchfield
Oracle DBA
http://www.niall.litchfield.dial.pipex.com
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