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OK. Weekend is over. Back to reality. We have probably beat this one to death and I suspect that there are more than a few out there that would not mind if this thread was ended. Anyhow, the discussion has been helpful. Rather than trying to respond to this latest round with a bunch of "yes, but's....", I am going to carefully consider all that I have learned, perform a thorough analysis, and then throw a dart. As usually is the case in this business, there is no definitive solution. At about $1,000 per disk drive, the more spindles route is actually less costly than $15,000 for a new tape drive (not to mention the closet full of 3570 tapes we have), but either way there is not much chance of returning the equipment if it does not get us the results we want. Unfortunately, with the economy in its current state, there is a reluctance around here to spend $ on any solution in the short term. Thanks to all that contributed. See you next time. Phil Message: 4 From: Chris Bipes <chris.bipes@cross-check.com> To: "'midrange-l@midrange.com'" <midrange-l@midrange.com> Subject: RE: Reducing downtime for backups Date: Fri, 30 Nov 2001 16:37:48 -0800 Reply-To: midrange-l@midrange.com But as you increase disk arms, i.e. drives, you get higher through put. As your through put goes up, your IOP, CPU and Main ASP Disk load will go up. Now if those do NOT become a bottle neck, you will still see 90+% disk utilization on your secondary ASP BUT your run time will go down. Any body want to back me up on this? And I do not take any offense to you or anyone on this list questioning what I post. Christopher K. Bipes mailto:ChrisB@Cross-Check.com Operations & Network Mgr mailto:Chris_Bipes@Yahoo.com CrossCheck, Inc. http://www.cross-check.com 6119 State Farm Drive Phone: 707 586-0551 x 1102 Rohnert Park CA 94928 Fax: 707 586-1884 -----Original Message----- From: prumschlag@phdinc.com [mailto:prumschlag@phdinc.com] Sent: Friday, November 30, 2001 1:22 PM To: midrange-l@midrange.com Subject: RE: Reducing downtime for backups Chris, Don't take this wrong, but I have trouble swallowing that. I have to go back to basics on this and in my (admittedly simplistic) view it goes like this: CPU - Fast; Disk - Not So Fast, Tape - Really Slow. For this job, the CPU has nothing else to do, so it will always be waiting on the disks, so no matter how many I throw at it the disk busy percentage will always be high. If my lousy memory serves me correctly, IBM invented *SAVF files for the express purpose of reducing downtime for backups. Has tape processing improved so much that one tape drive can record data faster than 6 read/write heads on disk? Or is it possible that the RAID processing on these disks is causing so much thrashing that the whole system is bouncing up and down in the computer room? Phil
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