Re: ASM or not to ASM
- From: "Tim Gorman" <tim@xxxxxxxxx>
- To: "Storey, Robert (DCSO)" <RStorey@xxxxxxxxxxxxxxxxxx>, "Oracle L" <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 11 Jul 2011 17:57:15 +0000
I've only rarely administered Oracle on Windows and the last RAC database on
Windows was 8.1.7.4 back in 2000 (I think it was still called "Parallel
Server"), so I have *nothing* to offer you. :-)
My instinct would be to leave well enough alone, but perhaps others on the list
can chime in.
-----Original Message-----
From: Storey, Robert (DCSO) [mailto:RStorey@xxxxxxxxxxxxxxxxxx]
Sent: Monday, July 11, 2011 11:41 AM
To: tim@xxxxxxxxx, 'Oracle L'
Subject: RE: ASM or not to ASM
Sorry, forgot to give you my system setup. I'm moving from 9i 32bit to 11gr2 64
bit. Windows 2008 server. My sysadmin has already carved out a huge chunk of
disk space for me and created my volumes. My limited understanding of ASM was
that (at least from a windows environment) that you setup the physical disks,
then created ASM. Once ASM was running, it took care of where it would store
data, where files would live, etc. As the DBA you didn't deal with storage
concerns other than balancing, and ensuring that you had enough space for
expansion.________________________________From: Tim Gorman
[mailto:tim@xxxxxxxxx]Sent: Mon 7/11/2011 11:55 AMTo: Storey, Robert (DCSO);
Oracle LSubject: Re: ASM or not to ASMRobert,My $0.02...The main thing that is
happening is that stuff which used to "belong" in the realm of "root" and the
Sys Admins are being moved under the realm of DBA. So, there is a huge
political aspect to the adoption of ASM that often overshadows the technical
aspect, and this political "shift of power" from Sys Admin to DBA can be more
of an obstruction than any other aspect of ASM adoption. Not sure what things
are like in your shop, but that is not a trivial concern.It would be inaccurate
to consider ASM to be "extra overhead". Along with that shift of "power" from
SysAdmin to DBA comes the shift in responsibility from "root" to "oracle"
accounts. If you are dealing with LUNs, volume managers, and file-systems, then
from a techical perspective using ASM is the exact equivalent. You still have
LUNs, but instead of a volume manager and a file-system you have ASM. Very very
similar, but running under "oracle" instead of "root". So you can see that the
big shift is human perception and responsibilities amongst the humans -- the
machine is still doing the same things.ASM is simpler to configure optimally
for Oracle than all of the flavors of file-system out there. Maybe you're
already comfortable with that, maybe not? Some folks constantly like to fiddle
with FS block-size, with direct-I/O, wish they could use asynch-I/O, etc. With
ASM, its part of enchilada from the start.Maybe you're using VxFS or some other
file-system with licensing issues; this is one area that Oracle actually saves
you a few bucks.Looking downstream, there are advantages with platform
migration/rehosting that come with ASM; not sure if that's slamming down the
turnpike toward you.Another big selling point with me personally is the ease by
which database files can be moved safely and without downtime from one SAN to
another using ASM; much easier than most other storage options. Run ALTER
DISKGROUP ... ADD DISK ..., ALTER DISKGROUP ... DROP DISK ..., then ALTER
DISKGROUP ... REBALANCE, and done.It's tough to answer with detail without
knowing present configuration, but that's my seat-of-the-pants reaction to your
question. If what you've got has worked well so far, then stick with it, but if
you reflect on things and realize that you're trying to make the square peg of
Oracle fit into the round hole of file-systems, then ASM can make life easier
and remove one more variable to worry about from the whole performance
optimization environment.Hope this helps!Thanks!-Tim -----Original Message-----
From: Storey, Robert (DCSO) [mailto:RStorey@xxxxxxxxxxxxxxxxxx] Sent:
Monday, July 11, 2011 10:30 AM To: 'Oracle L' Subject: ASM or not to ASM
Going through a 11gR2 new features class. First half day is all about ASM and
installing grid infrastructure for a standalone structure, My question is why
would I, on my single server with a single instance, using a SAN for my
storage, bother with ASM? Why do all of this overhead just for a single
instance? -- //www.freelists.org/webpage/oracle-l
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