Re: diskgroup calculations

From: just_real <jthlcf_at_gmail.com>
Date: Wed, 14 Jan 2009 20:09:23 -0800 (PST)
Message-ID: <003cae16-46a6-4062-b529-b91707a93baa_at_g39g2000pri.googlegroups.com>

On Jan 15, 12:36 pm, Steve Howard <stevedhow..._at_gmail.com> wrote:
> On Jan 14, 8:21 pm, just_real <jth..._at_gmail.com> wrote:
>
>
>
> > On Jan 15, 12:05 pm, Steve Howard <stevedhow..._at_gmail.com> wrote:
>
> > > On Jan 14, 7:56 pm, just_real <jth..._at_gmail.com> wrote:
>
> > > > Hi
>
> > > > I am using this query to display the size of the diskgroups in Oracle
> > > > and manually adding the figures up to get the total size of the
> > > > diskgroup.
>
> > > > select b.instance_name, a.LABEL,a.NAME,a.TOTAL_MB,a.GROUP_NUMBER from
> > > > v
> > > > $asm_disk a, v$asm_client b where a.group_number = b.group_number;
>
> > > > The question I have is:
>
> > > > 1. Is there a better way to work out the calculations of total
> > > > diskgroup size?
>
> > > > 2. The above query only works if the diskgroup is managed by ASM. What
> > > > would I be doing if there is no ASM? What would I have to change in
> > > > the query above?
>
> > > > Thank you.
>
> > > Hi,
>
> > > 1)  select total_mb,free_mb from v$asm_diskgroup;
> > > 2)  I don't understand the question.  What diskgroup is not is ASM?
> > > Do you mean a disk that is a candidate device, but not part of a
> > > diskgroup?  I think there is a column for that (state or status, I
> > > think), but I don't remember the name.  You can filter the correct
> > > column in v$asm_disk and sum the bytes to get the total size of
> > > devices not allocated.
>
> > > In linux, you can also do a...
>
> > > blockdev --getsize /dev/raw/$RAW_DEVICE_NAME
>
> > > HTH,
>
> > > Steve
>
> > Hi Steve
>
> > Thanks for the prompt reply. Sorry for my terminologies - still a newb
> > and just realised that diskgroups = ASM. I think what I was trying to
> > ask was how then would i calculate the size for a non-disk group.
>
> > I will try to paint a scenario - I've got A1, A2 are cluster databases
> > managed by ASM. Using the query that I had above would give me the
> > size of the A diskgroup. But on the same server is B on its own. So I
> > guess how would I calculate the size of the B filesystem? (i hope i am
> > making sense)
>
> > Thanks again
>
> I'm still not following.  Do you mean you have the following raw
> devices, with their ownership (or lack of) by an ASM diskgroup.
>
> /dev/raw/raw1 - GROUP1 (A in your example)
> /dev/raw/raw2 - GROUP1 (A in your example)
> /dev/raw/raw3 - Not part of ASM
> /dev/raw/raw4 - Not part of ASM
> /dev/raw/raw5 - GROUP2 (B in your example)
> /dev/raw/raw6 - GROUP2 (B in your example)
>
> Are GROUP1 and GROUP2 managed by the same ASM instance?  The answer
> should be yes :)  If so, then both diskgroups are fully available to
> any database instance that uses them for storage on that node.
>
> >> But on the same server is B on its own. So I guess how would I calculate the size of the B filesystem?
>
> If you wish to calculate the size of each diskgroup, I would use the v
> $asm_diskgroup view I mentioned earlier.  Also, since you mentioned a
> filesystem, you can have datafiles in both ASM and on a filesystem.
> ASM doesn't have to be used exclusively.
>
> HTH,
>
> Steve

ahhaah thanks for your response steve

I think this is what i was trying to say:

/dev/raw/raw1 - GROUP1 (A1+ in your example)
/dev/raw/raw2 - GROUP1 (A2+ in your example)
/dev/raw/raw5 - B
/dev/raw/raw1 - GROUP2(C1+ in your example)
/dev/raw/raw2 - GROUP2 (C2+ in your example)

hmmmm...does the above make sense? and yeah group 1 and group 2 in your description above are managed by the same ASM as you hinted :), Received on Wed Jan 14 2009 - 22:09:23 CST