This has been discussed before. If TSM mirroring and the error is a tsm error like the application failed, then only the tsm mirror that was being written to is corrupted. When the application comes back up it can detect and handle this. If it was hardware mirror only then the error will be written to all the disks and the application cannot recover from this due to the corrupted data is written to all disks by the hardware.
-- Phillip (901)320-4462 (901)320-4856 FAX -----Original Message----- From: Bernaldo de Quiros, Iban 1 [mailto:[EMAIL PROTECTED] Sent: Tuesday, September 19, 2006 7:52 AM To: ADSM-L@VM.MARIST.EDU Subject: Re: [ADSM-L] Best Practices DISK for DB, LOG, and STGPOOL && JigSaw Puzzle Hi all, Why to use TSM Mirror function for DB and RLOG if this can be supplied by Hardware RAID ¿? Using TSM mirror as far as I know could improve server performance... But is it recommended to have the two phylosophies HW RAID and TSM mirror ¿? Or only one of them... Pro's/Con's or preferences for HW RAID or TSM mirror ¿? Regards, Iban Bernaldo De Quiros Y Marquez Technical Specialist Sun Microsystems, Inc. Serrano Galvache, 56 Madrid 28033 ES Phone +34 91 767 6233 Mobile + 34 659 01 91 12 Email [EMAIL PROTECTED] -----Mensaje original----- De: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] En nombre de Richard Sims Enviado el: jueves, 14 de septiembre de 2006 17:21 Para: ADSM-L@VM.MARIST.EDU Asunto: Re: [ADSM-L] Best Practices DISK for DB, LOG, and STGPOOL && JigSaw Puzzle On Sep 14, 2006, at 10:59 AM, Bernaldo de Quiros, Iban 1 wrote: > Hi Richard, > > There's a lot of great stuff here and good advices !! > > But I have two last questions... > > 1-Will you share the same physical disk with database and storage pool > ¿? Never mix conflicting access-pattern subsystems in storage areas - that can be as bad as tape and disk on the same I/O path. It is essential that your database be as high-performance as possible, so keep it separate. > 2-Will you spread database volumes over the same physical disk or over > different physical disks ¿? Or will you make both ¿? In a non-RAID environment, I would spread over physical disks, to the extent reasonable. If very large disks, you may want a few partitions on the disk; but then try to use 15,000 rpm disks. But I prefer using raw logical volumes and hardware RAID 1+0 (striping and mirroring) for best performance. And beyond that there are sophisticated disk subsystems out there which offer further opportunities. Remember that TSM uses one thread per disk volume, so you gain by having a reasonable number of volumes. Look back in the List archives for information posted from the hard- won experiences of other contributors, as there's lots of good advice in our collective efforts. Richard Sims ********************************************************************* This message and any attachments are solely for the intended recipient. If you are not the intended recipient, disclosure, copying, use or distribution of the information included in this message is prohibited -- Please immediately and permanently delete.