Dumping over NFS

MFHorn arosen at hawk.ulowell.edu
Wed Apr 20 23:40:41 AEST 1988


Thanks.

This has probably come up before, but are there any ways to speed up [tar]
dumps of remote machines through NFS (besides 'get a faster machine/tape
drive')?  More specifically, I log on to an 11/785 running Ultrix 2.0, and
type "tar c /nfs".  /nfs is a remote partition mounted from a uVax II/GPX
(also running 2.0).  It dumps with no problems to a tu81, but it takes 2
hours for one tape (neither machine had any users at the time).

Sometime this summer we should have NFS on a DG MV/10000 SX (which is why
we'll have to use tar and not dump) with just over 1G of disk and only a
1600 bpi drive (~30+ tapes for a full dump).  We'll want to be able to dump
these disks to the tu81, but at 2 hrs/tape, it'll take almost an entire day.
[Not to mention the slew of disk/diskless workstations that might come in.]

I've tried playing around with the number of block I/O and mount daemons on
each machine; all combinations of each at 1 and 4.  The times were all about
the same.

Is it the Ethernet that makes everything so slow or can we cut this time
down some?  Is it the slow Ultrix tu81 driver or would 4.3 be faster?
One hour per tape would be great if we can get it.

Andy Rosen           | arosen at hawk.ulowell.edu | "I got this guitar and I
ULowell, Box #3031   | ulowell!arosen          |  learned how to make it
Lowell, Ma 01854     |                         |  talk" -Thunder Road
                   RD in '88 - The way it should be



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