ADSM-L

Data on 3570 tape

2000-05-11 10:32:05
Subject: Data on 3570 tape
From: "Loon, E.J. van - SPLXM" <Eric-van.Loon AT KLM DOT NL>
Date: Thu, 11 May 2000 16:32:05 +0200
Hi *SM-ers!
I'm currently testing our new TSM server.
During one of my test I discovered that the throughput from disk to tape and
from tape to tape was a little bit disappointing: about 6 Mbytes/sec. The
data rate for a 3570 unit should be 7 Mbytes/sec. sustained and 15
Mbytes/sec with 3:1 compression.
I checked the volume afterwards and I saw something else.
It's a 5 Gb. volume with 1.79 Gb of data on it. TSM reports that the tape
has a utilization of 34.2%. So 1.79 Gb. divided by 34.2 times 100 makes a
tape capacity of about 5.2 Gb.
I know for sure that the data that has been send to TSM is uncompressed
data, so that is why I'm thinking that the tape unit is NOT compressing the
data!
Is unit compression a feature you have to turn on manually? If so, where do
you control this?
Thanks in advance for your reply!
Kindest regards,
Eric van Loon


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