Subject: RE: FLASHCOPY performance to a DS6800 DASD
From: Eric Schadow (eschadow@davisvision.com)
Date: Wed Jul 16 2008 - 10:17:48 EDT
Ed
The flash doesn't actually copy the data that quick. It just starts to copy the data then says ok it's complete as the copy is done on the background. If a track of data on the source volume is changed before it is copied the target then the 6800 keeps track of it automagically.
ESCON to FICON gained you most of the performance gain.
Do you have any I/O stats?
Are you z/vm?
Do you run MDC?
Is CPU pegged during the batch?
-----Original Message-----
From: owner-vse-l@Lehigh.EDU [mailto:owner-vse-l@Lehigh.EDU]On Behalf Of Edward M. Martin
Sent: Wednesday, July 16, 2008 10:00 AM
To: VSE Discussion List
Subject: FLASHCOPY performance to a DS6800 DASD
Hello Everyone,
I need some confirmation. I am just amazed at the performance of the DS6800
I just did the z/VM command FLASHCOPY on a 3390-mod 9 on DS6800 to another 3390-mod 9 volume on the DS6800.
FLASHCOPY 8A2 0 END TO 8A1 0 END SYNCHRONOUS
The command responded instantaneously.
SYNChronous
tells CP to process the command immediately and does not allow you to
enter any other commands until the hardware has accepted all parameters,
all messages from the Enterprise Storage Server (ESS) subsystem have been
processed, and the FLASHCOPY command completes.
Is the DS6800 and the FLASHCOPY really that fast or is there something going on behind the
scenes?
Performance has been pretty unbelievable but the FLASHCOPY was just too fast.
Example Our Batch cycle at night use to take 5-5.5 hours. Started at midnight and
Completeed around 5:30 am.
Old system EMC SYMETRIC 8 gig of cache and 6 ESCON connections.
SWITCH to DS6800.
DS6800 2 gig of cache with 4 FICON connections.
Batch cycle dropped by 1 hour without any other changes. Start at midnight and completes
around 4-4:30 am.
Ed Martin
330-588-4723
ext 40441
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