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From: dbfunk@ICAEN.UIOWA.EDU (David B. Funk)
Newsgroups: comp.sys.apollo
Subject: Re: 8mm backup. Time required to back up 2.3 gb
Message-ID: <8812100434.AA00493@umaxc.weeg.uiowa.edu>
Date: 10 Dec 88 04:12:43 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: Iowa Computer Aided Engineering Network, University of Iowa
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WRT posting <423@caldwr.UUCP> from kwongj%caldwr.uucp@ucdavis.ucdavis.edu (James Kwong)

> Could someone please tell me how long it would take the
> Workstation Solution 8mm tape unit to back up 2.3 gbytes.

We find that our W.S. exatape runs at 200 megabytes / hour, average,
using regular wbak on a full backup. We have it connected to an 8MB DN4000.
The exact rate will depend upon the speed of the nodes that the disks
are attached to and the network load.

When we used a CDC Keystone tape drive (MSD6250) we got 120 MB /hour
average, with regular wbak, and 200 MB /hour using W.S. tbs_wbak
in interleaved mode. I would imagine that a 1600 BPI would be comparable
for speed, if you could swap tapes fast enough to keep it busy.

We've not tried W.S. tbs_wbak on the exatape yet, but I would expect
it to be even faster.

Dave Funk
University of Iowa