My 3584 has FC-AL drives through McData ES-1000 switches
to a RS6000 6H1 with the FC 6228 2 Gigabit Adapters.
Tape to tape I get about 115GB /hour and as you mentioned 2.5/1
or slightly better compression - compressing on tape only.
David Longo
>>> nickpc AT US.IBM DOT COM 07/03/02 01:40PM >>>
How much data was actually on the tape? If you got 2:1 compression, at 25%
full, an LTO tape has 50GB of data on it. Over 4 hours that's 12.5GB/hr,
which may not be too bad depending on the connection to the drives. And
if, as I've seen, you get better than 2:1, say 2.5:1, you're looking at
63GB of data, or just over 15GB/hr.
There are a number of factors that can go into the performance. Bandwidth,
from the SCSI bus or SAN, the PCI bus the data is flowing over, the TSM
database (was expiration running at the same time, causing the reclamation
to kick off?), all kinds of things like that can slow down reclamation.
Since you only have two drives, you may want to look at a reclamation pool.
Granted, you'll need some DASD to do it - if you're tapes are holding 200GB
and your reclamation threshold is 60%, you're looking at 80GB of data to
reclaim a tape. But it would keep a drive free for user functions.
Nick Cassimatis
nickpc AT us.ibm DOT com
Today is the tomorrow of yesterday.
Guillaume Gilbert
<guillaume.gilbert@DESJ To: ADSM-L AT
VM.MARIST DOT EDU
ARDINS.COM> cc:
Sent by: "ADSM: Dist Subject: Reclaiminig LTO
Tapes
Stor Manager"
<ADSM-L AT VM.MARIST DOT EDU>
07/03/2002 09:40 AM
Please respond to
"ADSM: Dist Stor
Manager"
Hey there
Maybe its because I'm used to using STK 9840 tapes but yesterday I saw an
LTO tape at 25 % utilisation take almost 4 hours to reclaim, which to me is
awful. How am I
supposed to reclaim my tapes with that kind of performance?. The drives I
use are IBM Ultriums in a 3584 library. With only 2 drives it makes it hard
for users to do
restores...
Are there any options I can change to make this go a bit faster. I know the
start/stop on LTO's isn't good.
Thanks for the help.
Guillaume Gilbert
CGI Canada
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