Are incremental backups possible/safe?

imagirlgeek · 08-25-2004, 02:20 PM

Hello -

I need to conserve space on my backup drive .... are incremental backups safe, or are full backups my best bet?

If I'm better off using incremental backups, what syntax should I be using?
For full, I'm currently using the command:

tar - czvf /directory/to/backup/to/backup.tgz /directory/to/backup

Any advice would be greatly appreciated! I am sort of under the gun. Thanks!!

Tinkster · 08-25-2004, 03:17 PM

Hi, and welcome to LQ!

The question is not which is better, the questions is
what are you trying to achieve? :)

Cheers,
Tink

imagirlgeek · 08-25-2004, 03:27 PM

Hi Tink,

Thanks ... I'll give some background.

I am at a small company that hosts maybe 6 or 8 client websites and log files ... the log files get very large in time. I have been instructed to do nightly backups of our server, which I place on a secondary backup drive - but there's only room for about 10 .gz files before the disk space is completely used up.

We have a machine here in the office on which I can store archived backups, but I learned pretty quickly that ftp-ing a 2gig file takes several hours! I thought that if I could do a weekly full backup, and then incremental backups for the four other days, that might be more efficient. I'd be able to download the backups more quickly to the "archive" machine and I'd be able to store more on the secondary server.

I hope that makes sense. Thanks!

Tinkster · 08-25-2004, 04:09 PM

Quote:

Originally posted by imagirlgeek
Hi Tink,

Thanks ... I'll give some background.

I am at a small company that hosts maybe 6 or 8 client websites and log files ... the log files get very large in time. I have been instructed to do nightly backups of our server, which I place on a secondary backup drive - but there's only room for about 10 .gz files before the disk space is completely used up.

Are you using logrotate to break the logs down
into chunks of a more manageable size?

Quote:

We have a machine here in the office on which I can store archived backups, but I learned pretty quickly that ftp-ing a 2gig file takes several hours!

What type of server hardware are you writing to,
what kind of connection are we talking here? On a
100MBit full duplex I'm getting a throughput of around
9.7MB/s ... that should make around 4 minutes for 2 Gigs.

Quote:

I thought that if I could do a weekly full backup, and then incremental backups for the four other days, that might be more efficient. I'd be able to download the backups more quickly to the "archive" machine and I'd be able to store more on the secondary server.

I hope that makes sense. Thanks!

Does make sense, question is how fast a disaster-
recovery would be possible. Have you got a clone
of the base installation somewhere on a spare HDD
or something?

Cheers,
Tink

chrism01 · 08-25-2004, 04:11 PM

If you use rsync, it will automatically create or update (ie differences only) the tgt files as appropriate. It also does compression, which will speed things up across the lan, and you can also ask it to use ssh encryption if you eventually decide to send backups out of the office ... or just want them inaccessible to unauthorised people.