Backup Central

Way back when I had some tape drives. At that time Linux could not
provide compression on tape drives. Especially if you where trying to
write across multiple tapes.

Is this still true?

So if I'm looking at a tape drive that says it is an 80/204GB type, I
should use 80GB for my calculations?

Sent from my iPhone.

On Feb 18, 2008, at 1:01 PM, Tom Allison wrote:

Way back when I had some tape drives. At that time Linux could not
provide compression on tape drives. Especially if you where trying to
write across multiple tapes.

Is this still true?

So if I'm looking at a tape drive that says it is an 80/204GB type, I
should use 80GB for my calculations?

Compression is a hardware issue. It is not done by the OS.

What calculations?


Sent from my iPhone.

Please, this is not the place for complaints. :)

--
Dan Langille -- http://www.langille.org/
dan < at > la...

On Feb 18, 2008 1:01 PM, Tom Allison <tom < at > ta...> wrote:
Way back when I had some tape drives. At that time Linux could not
provide compression on tape drives. Especially if you where trying to
write across multiple tapes.

Is this still true?

So if I'm looking at a tape drive that says it is an 80/204GB type, I
should use 80GB for my calculations?

Linux will provide compression if the hardware supports it. It's just
that the 204 GB number is a highly optimistic number that one will
rarely see in real life. 1.5:1 is more realistic for my data so the
drive for me would be a 120GB drive...

John

Dan Langille wrote:

On Feb 18, 2008, at 1:01 PM, Tom Allison wrote:

Way back when I had some tape drives. At that time Linux could not
provide compression on tape drives. Especially if you where trying to
write across multiple tapes.

Is this still true?

So if I'm looking at a tape drive that says it is an 80/204GB type, I
should use 80GB for my calculations?

Compression is a hardware issue. It is not done by the OS.

What calculations?


So I can expect that whatever is under the hood for Bacula to get me
some compression (I agree with the 1:1.5) for the tape drive.

I'm trying to see how much space I need to back up three macbooks and
three debian servers. Using my own macbook as the worse case situation
I have 20GB in $HOME, 21GB in /opt, and 66GB used in total.

Sorting out junk and stuff that I can reinstall via ports, I have
40-50GB of usable space that I'll eventually need to keep backed up.

As a guess I assumed 1.5 to 2.0 times more space in a backup of said
computer. So this means I should have ~80GB for one macbook. Something
like that.

Those calculations?