Path: utzoo!attcan!lsuc!maccs!dan
From: dan@maccs.dcss.mcmaster.ca (Dan Trottier)
Newsgroups: comp.arch
Subject: Re: disk allocation strategy
Message-ID: <2663C6C4.22194@maccs.dcss.mcmaster.ca>
Date: 30 May 90 13:12:36 GMT
References: <1990May24.071122.7009@hawkmoon.MN.ORG> <1990May28.232017.9279@indetech.com>
Organization: McMaster University, Hamilton, Ontario, Canada
Lines: 37

In article <1990May28.232017.9279@indetech.com> david@indetech.com (David Kuder) writes:
>In article <1990May24.071122.7009@hawkmoon.MN.ORG> det@hawkmoon.MN.ORG (Derek E. Terveer) writes:
>>One potential problem that i see is how to back up distributed user's
>>directories.  If they are centralized, they can be more easily backed up.
>
>One strategry that has been re-invented in several different forms is
>to copy the data on local disks onto the central servers.  The schemes
>range from doing network file system mounts, to doing backups on the
>individual machines and shipping the tape images over the net to the
>fileserver.  Check out the proceedings of the Large System
>Administration conferences held by Usenix the last several years for
>details.

We back up clients machines from the fileservers via the rdump command.
The difficult part was deciding on how to coordinate the dumps. The
solution was to run everything from one of the servers and use the 
following commands to dump the clients:

# For each host in hosts[x] 
while ( $i <= $#hosts ) 
  # and its corresponding filesystems listed in fs[x]
  foreach j ( $fs[$i] )
    # start up rdump on each system to do the actual dump
    rsh $hosts[$i] ${rdump} ${dhost}\:${dev} $j >>& ${dumplog}.${ext}
  end
  # move on to the next host
  @ i++
end

This is run in the middle of the night and dumps incremental backups to
and exabyte drive. The dump level can be controlled to either maximize
file recovery or minimize tape usage.

-- 
Dan Trottier                                       dan@maccs.dcss.McMaster.CA
Dept of Computer Science                       ...!uunet!utai!utgpu!maccs!dan
McMaster University                                      (416) 525-9140 x3444