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> Privileged/Confidential Information may be contained in this message or attachments hereto. Please advise immediately if you or your employer do not consent to Internet email for messages of this kind. Opinions, conclusions and other information in this message that do not relate to the official business of this company shall be understood as neither given nor endorsed by it.