RE: Oracle's ASSM
- From: "Allen, Brandon" <Brandon.Allen@xxxxxxxxxxx>
- To: <DGoulet@xxxxxxxx>, <niall.litchfield@xxxxxxxxx>
- Date: Tue, 13 Sep 2005 09:44:28 -0700
See comments below:
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]On
Behalf Of Goulet, Dick
Sent: Tuesday, September 13, 2005 7:33 AM
To: niall.litchfield@xxxxxxxxx
Cc: oracle-l@xxxxxxxxxxxxx
Subject: RE: Oracle's ASSM
Oracle is telling us that ASM or OMF whichever you like is a mandatory
part thereof. This poses a number of problems. First of which is damanagement
which wants a change control form every time a data file does an auto extend.
And a number of tablespaces that we don not want extending because we put data
therein that is to be archived off to CDROM, consequently it's necessary for
the process loading these tablespaces to error out every once in a while.
[Allen, Brandon] I don't believe using ASM and/or OMF prevents you from turning
off auto extend on the datafiles. Here is some text from the Oracle online
docs (
<http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96521/omf.htm#1656>
http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96521/omf.htm#1656):
Oracle-Managed Files and Existing Functionality
Using Oracle-managed files does not eliminate any existing functionality.
Existing databases are able to operate as they always have. New files can be
created as managed files while old ones are administered in the old way. Thus,
a database can have a mixture of Oracle-managed and unmanaged files.
By default, an Oracle-managed datafile for a regular tablespace is 100 MB and
is autoextensible with an unlimited maximum size. However, if in your DATAFILE
clause you override these defaults by specifying a SIZE value (and no
AUTOEXTEND clause), then the datafile is not autoextensible.
And from
http://download-west.oracle.com/docs/cd/B19306_01/server.102/b14231/storeman.htm:
Creating Tablespaces in ASM
When ASM creates a datafile for a permanent tablespace (or a tempfile for a
temporary tablespace), the datafile is set to auto-extensible with an unlimited
maximum size and 100 MB default size. You can use the AUTOEXTEND clause to
override this default extensibility and the SIZE clause to override the default
size.
Now I've never been an advocate of anything new that Oracle pops out of the
factory until it's had some filed experience, read that as Not in it's first
version. And I'm very skeptical of not knowing what is in what tablespace,
especially when a hot disk pops up. We've used stripping and raid in the past
with some really undesirable side effects, like mass writes taking forever
[Allen, Brandon] Sounds like maybe you were using RAID5 (striping w/ parity),
which is notoriously poor for write performance. Try RAID10 (striping and
mirroring) instead
and having to add more devices than we have to extend a mount point, and the
resulting device additions to all of our Business Continuation Volumes.
Basically trying that again is a definite no-no around here. True everyone
says disk is cheap, unless you don't have them available.
<http://www.niall.litchfield.dial.pipex.com>
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