Mark I totally agree with your logic and in any other environment, hardware mirroring would be a given. However, a few years back, I was involved in a database corruption scenario. An unscheduled outage took down a TSM server. At the time, the database was H/W mirrored with battery backed up cache. A partial page write occurred, that was mirrored to both plexes. When bringing the system back up, TSM deemed the DB to corrupt and a DB restore was required
The advice from IBM at the time, was that you should always use TSM s/w mirroring with MIRRORWRITE Sequential. I have carried on adhering to this through the years, however, I would be interested in hearing if this is no longer the case and the "partial page write" scenario is no longer an issue. Leigh -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of Mark Stapleton Sent: 07 February 2006 14:22 To: ADSM-L@VM.MARIST.EDU Subject: Re: [ADSM-L] Database mirroring, again "ADSM: Dist Stor Manager" <ADSM-L@VM.MARIST.EDU> wrote on 02/06/2006 01:07:08 PM: > I know we've been over this, but times change, and technology changes. > Conventional Wisdom on this list has been that the best disk layout for > your TSM Database is: > > JBOD disks, Raw volumes, mirrored by TSM, with 2 dbvols per physical > volume. One note about conventional wisdom: *always* mirror with hardware when possible. Hardware mirroring is faster and more stable. (Hardware anything--mirroring, compression, encryption, etc.--is almost always faster and more stable.) The only reason TSM ever contained dbvol and logvol mirroring abilities was to accommodate the ADSM server port to Windows, which at the time had no mirroring capabilities. -- Mark Stapleton ([EMAIL PROTECTED]) US Bank Backup and Recovery Management Office 262.790.3190 ------------------------------------------------------------------------ ------ Electronic Privacy Notice. This e-mail, and any attachments, contains information that is, or may be, covered by electronic communications privacy laws, and is also confidential and proprietary in nature. If you are not the intended recipient, please be advised that you are legally prohibited from retaining, using, copying, distributing, or otherwise disclosing this information in any manner. Instead, please reply to the sender that you have received this communication in error, and then immediately delete it. Thank you in advance for your cooperation. ======================================================================== ======