RE: > 2 Tb disk under ASM - RHEL 5.3/11.2.0.3

  • From: "Mark W. Farnham" <mwf@xxxxxxxx>
  • To: <gcunningham@xxxxxxxxxxxxxx>, <tim@xxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
  • Date: Tue, 10 Jan 2012 10:48:08 -0500

Tim nailed it that the patch prevents you from adding a disk all the sectors
of which cannot be addressed.

As for the workaround, if I recall correctly your options are to move to
disks with a 4K underlying sector size (as opposed to 512 so ASM can address
a factor of 8 more sectors), or carve up the LUN you are presenting as a
disk into pieces small enough to be addressed. 

Notice that the larger sector size just bumps the address space issue up. As
the available disk sizes get bigger and leap ahead of the addressable sector
size (for lots of good reasons for both spinning and electronically
addressed media) this figures to be something you do have to think about if
you want to use really big pieces of storage assembling your media farm for
ASM to manage.

All the fun stuff about grouping "disks" together in similar units of IO/s
and speed within a diskgroup then apply, but at least with ASM you get to do
that once at the media level. If you have hardware with varying speeds and
geometries, that is a pretty doggone good reason to have more diskgroups,
one each type you're putting data on (in addition to diskgroups you don't
put data on).

In handling this, try to be as BORING as possible in the assemblage of disks
into stripesets so you have a ghost of a chance of understanding how to
minimize interLUN interactions. If you allocate the LUNs reasonably SANELY,
ASM should do a reasonable job of the rest. If you carve the LUNs up in a
HAPHAZARD way, ASM will still do a correct job but the result may be lousy
throughput compared to what is possible because it does not have a way to
know things you present to it interact with each other or are pieces of the
same thing (nor should it, in my opinion).

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of Gerald Cunningham
Sent: Monday, January 09, 2012 10:53 PM
To: tim@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: RE: > 2 Tb disk under ASM - RHEL 5.3/11.2.0.3

Thanks Tim!

I think you are right...


Jerry
________________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx [oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Tim Gorman [tim@xxxxxxxxx]
Sent: Monday, January 09, 2012 7:23 PM
To: Gerald Cunningham; oracle-l@xxxxxxxxxxxxx
Subject: Re:  > 2 Tb disk under ASM - RHEL 5.3/11.2.0.3

Yes, we ran into it under 10.2.0.x. Actually what happened is that 10gR2 ASM
permitted us to create the huge ASM disk (no error message), but then gave
errors after ASM tried to use the space above 2 Tb, several months later,
resulting in corruption which led to a 14 Tb tablespace recovery.
Since the patch in 10gR2 was only supposed to throw the error when you tried
to add a disk larger than 2 Tb, I think you are seeing the correct
post-patch behavior. The patch throws the error -- it still does not permit
you to add a disk larger than 2Tb. I could be wrong, but be sure to look at
the notes in Support with that possible understanding...



-----Original Message-----
From: Gerald Cunningham [mailto:gcunningham@xxxxxxxxxxxxxx]
Sent: Monday, January 9, 2012 04:49 PM
To: 'Gerald Cunningham', oracle-l@xxxxxxxxxxxxx
Subject: RE: > 2 Tb disk under ASM - RHEL 5.3/11.2.0.3

slight correction 2097152 *Mbs*________________________________________From:
oracle-l-bounce@xxxxxxxxxxxxx [oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of
Gerald Cunningham [gcunningham@xxxxxxxxxxxxxx]Sent: Monday, January 09, 2012
6:35 PMTo: oracle-l@xxxxxxxxxxxxxxxxxxxx: > 2 Tb disk under ASM - RHEL
5.3/11.2.0.3All,I'm getting the following error when trying to add a 3 Tb
ASM disk under 11.2.0.3 ASM on REL 5.3:ORA-15099 disk  is larger than the
maximum size of 2097152 bytesLooks like it may be bug 10072750 or
6453944.8...Has anybody run into this? Is there a patch or workaround? The
patch set notes for 11.2.0.3 say this is supposed to be fixed.Thanks very
much for any help,Jerry--//www.freelists.org/webpage/oracle-l--Follow
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