Yet another opinion: If you are running TSM HSM, that requires 24x7 availability. Then you should mirror both DB and logs.
If you are NOT running TSM HSM, a lot of TSM installations can actually afford to have TSM down a couple of hours. SO what I usually do, when I have the DB on a RAID device, is just to mirror the recovery log. That way, if you DO lose the DB due to some type of logical corruption, you can always restore from your last DB backup, and roll forward from the log. So you lose no data, just some time. It's adequate protection, if you can afford the time. (That assumes you run in ROLLFORWARD mode, which you SHOULD be doing, and you are very religious about your DB backups, which you SHOULD be!) -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of Joerg Pohlmann Sent: Thursday, April 07, 2005 10:38 PM To: ADSM-L@VM.MARIST.EDU Subject: Re: Question on SETUP Hi Paul. From bitter experience I have been saved by TSM mirroring on nicely protected disks. I have had complete filesystems clobbered as result of other hardware failures, nothing to do with the disks - have had filesystems damaged on AIX and also Windows. TSM mirroring is such a superb, inexpensive protection against these other failures that I always recommend TSM mirroring. It's also quite inexpensive give todays cost of disk storage, including Shark. And yes, on a Shark I would create four filesystems (/tsmdb1 /tsmdb2 /tsmlog1 /tsmlog2 - Windows an D: E: F: and G: drive) so that the 1s and 2s (or the E: and G: drive) are in different LSSs. And yes, I wear belt and suspenders. Joerg Pohlmann 604-535-0452 Paul Fielding <[EMAIL PROTECTED]> Sent by: "ADSM: Dist Stor Manager" <ADSM-L@VM.MARIST.EDU> 2005-04-06 23:25 Please respond to "ADSM: Dist Stor Manager" To ADSM-L@VM.MARIST.EDU cc Subject Re: Question on SETUP I don't see the value in mirroring the db and logs if they're placed on Shark disk. The purpose of TSM's mirroring is to provide disk redundancy in case of disk failure. However, the Shark provides it for you. Why add the extra overhead of software mirroring when the hardware does a valiant job in the background. The Quck Start recommendation doesn't take into account that your disk is already protected... regards, Paul ----- Original Message ----- From: "Jones, Eric J" <[EMAIL PROTECTED]> To: <ADSM-L@VM.MARIST.EDU> Sent: Wednesday, April 06, 2005 2:56 PM Subject: [ADSM-L] Question on SETUP > Good Afternoon. > I was asked to setup a new TSM server 5.2.2 on a AIX 5.2 server. > My question has to do with setting up the DB, LOG and DISKPOOL. > On our current servers which run the same O/S and TSM version the DB, LOG > and DISKPOOL are mirrored. > On the new system I'm setting up these are all going to reside on a IBM > SAN(SHARK) which is all RAID. > Is there any reason to mirror them since the mirror would be on the same > set of drives(space was already allocated on a LUN)? > I understand it's always good to mirror(protect DB, LOG, DISKPOOL) but in > this case I'd have to mirror to the same set of disk since I was only > allocated a set of space to work. In the TSM class it also recommended > that you mirror for protection. > I'm in the middle of reading the "Quick Start" for the second time and I > see they recommend "Mirror your Database and recovery log for "Server and > storage pool protection". I wanted to make sure there was not a > performance issue or anything else. > > Have a Great Day, > Eric Jones >> * [EMAIL PROTECTED] >> *: 607-751-4133 > Cell : 607-972-7621 >
