Re: Multisystem backup
On Wed, 3 Nov 1999, Marcin Pacyna wrote:
> prompts. Also I think there is a way to use rsync over ssh, just look
> for an SSH FAQ - I think that's where I saw this.
You only need to set the environmental variable RSYNCH_RSH=ssh to make it
work. rsync has proven very reliable and and very flexible. I use it, as
an example, to keep my password files in sync. I have done so for several
months now with no apparent problems using ssh's update mode. Only the
diff in /etc/shadow that is traveling the network when somebody changes
their password.
Rsync is also very nice to use for backing up one partition to another on
the same box. My "most important box" uses rysnc to "clone" of the
primary drive to a backup that otherwise sits idle and unmounted. A
judicious selection of files for rsync to skip and my LILO configuration
lets me boot off the backup ... with the added bonus of the primary drive
sitting there unmounted. A boot floppy provides yet another alternative
to keep the server running.
NFS is a solution to a problem that I do not have providing PPP
connections and domain hosting. I have a small local network and it was a
lot easier to buy a bigger hard drive. Each box has more than enough disk
space to do it's thing. Mounting remote disks to provide a shared
resource was unnecessary. I do not provide shell login access, so users do
not need to mount home directories from another computer either.
I use vixie cron to call tiny bash scripts to test conditions and run
rsync if required. Cron provides permissions and frequency control. Rsync
provides the network link and content control. Ssh provides security. A
typical "Unix toolbox" solution to my requirements. Concurrency is a
demand I do not need to satisfy at this stage. If I did, I would likely go
to a RAID solution. I use ssh to stop and start remote servers. I use
syslogd's remote logging feature to keep an eye on what I want to know
about the other systems.
I don't quite get the implication of "other jobs to finish first" ... what
jobs? On which computer? How many jobs on how many computers? What would
you need to know that could not be scheduled through cron or tested via
a bash script calling ssh?
Your file recovery question also muddles my brain with questions. Has the
other system crashed? Do you have physical access to one or both
computers? Is it available through the network? What exactly are you
trying to recover and is the recovery time critical?
My own concern leans more to be able to bring up a backup webserver on a
different box so I can bring the primary down for maintenance. Being able
to do it dynamically would be a secondary concern. The necessity to keep
log files and arp caches healthy, along with bringing down/up the network
interfaces makes the solution look more risky than the problem. With good
hardware, dpkg/apt to keep system software up to date and linux
reliability, I do not have much demand for that scenario either. I have
physical access to all computers and I can live with the downtime when I
make mistakes.
>
> Marcin P.
>
> On Wed, 3 Nov 1999, Jaysen O'Dell wrote:
>
> > Ok I finally need to build a central backup "server". Looking at
> > utilizing an old p233 w/64Mram, 10bT NIC and an 8GB HD w/ the spud for
> > our deb release. Here are the concerns that I have:
> >
> > 1) Is NFS a good idea? I am nervous about the obvious solution of NFS
> > mount then tar the files. security is the obvious concern but what about
> > locking and access.
> >
> > 2) Is there a solution that will run client side but still wait for
> > other jobs to finish first?
> >
> > 3) What solutions are actually out there that allow recovery of files
> > from other systems?
> >
> > I know this seems really open but I don't want to "lead" responses.
> >
> > TIA
> > --
> > Jaysen
>
>
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Gerard MacNeil, P. Eng macneil@supercity.ns.ca
System Administrator
Supercity Internet Services http://www.supercity.ns.ca
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