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From: wsmith@umn-cs.CS.UMN.EDU (Warren Smith [Randy])
Newsgroups: alt.sys.sun,comp.unix.questions
Subject: Re: Question about dumps on Suns
Keywords: dumps, single user
Message-ID: <17483@umn-cs.CS.UMN.EDU>
Date: 6 Dec 89 22:43:23 GMT
References: <21436@adm.BRL.MIL> <2643@auspex.auspex.com> <10138@stag.math.lsa.umich.edu> <433@lectroid.sw.stratus.com> <18506@bellcore.bellcore.com>
Reply-To: wsmith@umn-cs.cs.umn.edu (Warren Smith [Randy])
Organization: CSci Dept., University of Minnesota, Mpls.
Lines: 36

In article <18506@bellcore.bellcore.com> tr@bellcore.com (tom reingold) writes:
#
#On the subject of "Question about dumps on Suns",
#todd@lectroid.sw.stratus.com (Todd Joseph) writes:
#
#$ I'm performing dumps on a Sun server with an Exabyte 8mm backup system.  
#$ Dumping to an Exabyte takes a long time.  Consequently, performing dumps in 
#$ single-user mode takes the server out of use for a long time.  Does anyone 
#$ have experience with performing dumps in multi-user mode?
#
#It's not "supposed" to be a good thing, since you can lose some files
#while you back them up, but it's the only way I do backups, and I
#haven't had a disproportionate number of problems resulting from it.
#That is to say that the benefit of not taking the system down seems to
#outweigh the inconvenience of the occasional lost file.
#
#Tom Reingold                   |INTERNET:       tr@bellcore.com

I agree whole-heartedly.  A couple of additional notes:
  a) Since you can generally do exabyte dumps unattended you can dump
     the whole system in the wee morning hours.  Not many people are
     manipulating the filesystem at 2am.  Even though we have many
     night owls usage is still low.
  b) Since you can backup the system every day you are almost certain
     to have a copy of a file valid within 2 days.  In practice I can't
     recall ever not finding files that we needed on the tape I looked for
     them on.

If you have some application running in the early morning hours that does
significant filesystem manipulation your mileage may vary...

Randy
-- 
Randy Smith
wsmith@umn-cs.cs.umn.edu
...!rutgers!umn-cs!wsmith