RE: Reducing downtime for backups

[prumschlag@xxxxxxxxxx]

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