Re: Datafile and disk path for ASM
Date: Fri, 12 Oct 2012 18:49:26 +0200
Message-ID: <CALH8A92nO52mFCSOV6zuUH4uYDhBu-DZ_h=h+AD4Cb488OPSqg_at_mail.gmail.com>
Sreejith,
there is no simple mapping DISK <-> datafile.
I try to summarize it a little bit:
Every diskgroup can have many physical disks.
Every disk in a diskgroup is split into equal pieces - Allocation Units (AU)
Every file in a diskgroup is spread evenly across different AUs on all
disks available.
With redundancy it's even more complex.
So generally speaking, your disk sd9 will probably contain pieces of all datafiles within the diskgroup.
You should see a similar utilisation of all disks within the diskgroup.
If you really see only this particular disk with high IOs & queueing, you must figure out your hot block.
Maybe this will help as a starting point:
http://asmsupportguy.blogspot.co.at/2011/06/asm-file-extent-map.html
hth
Martin
On Fri, Oct 12, 2012 at 8:27 AM, Sreejith S Nair < Sreejith.Sreekantan_at_ibsplc.com> wrote:
> Hi List,
> I am sure people may have already thought about this and have a solution,
> I am unable to find that info now !
>
> So we have few 11.2.0.2 databases monitored by EM 12c on a two node RAC.
> We got an alert for one disk sd9 , 98 % busy from Host monitoring
> capabilities of EM.
> I am trying to figure out what all datafiles ( of databases) are in this
> disk.
>
> I got the slice which corresponds to this disk(sd9) from our SA. I checked
> v$asm_disk where I can see the PATH, disk group etc. I can see all
> datafile names from v$asm_alias.
>
> But I could not understand how I will be able to see what all datafiles of
> particular databases are in this disk. Then I will be able to understand
> which all datafile writes/reads are contributing to this.
>
> Thanks in advance.
>
> With Regards,
> Sreejith
>
> --
> Sreejith
> Sr Database Administrator
> sreejithsna.wordpress.com
>
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