Am Mit, 2003-06-25 um 10.48 schrieb Paul Bijnens:
> Heinz-Josef Claes wrote:
> > following scenario: The data from the file and print servers is
> > synchronised in the night via rsyc to some cheap servers with fat disk
> 
> Amanda with client side compression (the default setup for many
> people) can achieve the same effect (although not as efficient
> as rsync, but not that far either).  Amanda spreads out the backup
> over the dumpcycle so that each night it has to do about the same
> amount of work.
> 
> I know, it's a different approach than many (most?) other backup
> schemes, but in reality this work very well.
> 
> The holdingdisk feature of amanda (your "fat disk") is an integral
> part of the system, and makes it possible to start many (slow) backups
> in parallel, and, at the same time, writing to the tapedrive in top speed.
> 
> (Of course your other reasons to use your planned setup with 
> storeBackup, fast/easy restores by users etc are still valid. And
> indeed, rsync can mirror your filesystems even faster.)
> 
The problem of the backup to tape is, that it is not possible to make a
full backup, because the wide area network doesn't have the capacity for
that. This is one reason for using rsync, because rsync has to make only
an "incremental" backup every night. The full backups to tape can then
be made locally from the "fat" servers.
The other reason for using the "fat" servers as mirrors for the night is
as follows: If one of the file and print servers is totally broken (can
not be repared fast), the "fat" server can be used (via WAN) as file 
and print server via redirect until a new file and print server is
installed.
Unfortunately, compression cannot be used because all files on the
servers are encrypted (encryption / decryption is done from the
clients).

> > decision up to know about this. -> So, amanda has a lot of time to do
> > the backup, there are only a few clients (with big storage) to the
> > servers (with the robots) and perhaps we can use less robots because we
> > will not do a daily backup.
> 
> Beware that Amanda works faster/better with many smaller clients than
> with few big clients.  There can be more done in parallel if you have
> more clients.
> 
But it should be ok if the backup is done from local disks or via
Gigabit Ethernet directly to tape!?

> About 6 years ago, I worked in an environment with 8 big servers
> and each had a tape drive dedicated. The backup, with a home made
> script, took about all night on some systems, just completed in time
> before the first people started coming in.
> Then I switched companies, and learned about Amanda.  In my current
> config I do my daily backups with 1 tape drive and I have about 25
> servers (big and small) + 12 MSWin systems to backup.  The total amount
> to backup is 12 times more than before.  And my backup time each night
> takes only 3.5 hours.
> 
> I also have an "archive" run each weekend (only full backups) to
> 2 drives (+ one flush on a third tape on monday morning).
> This takes only 8.5 hours. However, if I had to serialize all
> those backups it would take 42 hours. Amanda makes it possible to
> squeeze those 42 hours in less than 9 hours.
> 
> If someone told me that 6 years ago, I wouldn't believe him.
>