Sorry for the length of the email, but it's been a bit difficult to
explain everything... :-)
Hi there,
I'm wondering which is the best backup technique that I can implement
on a Linux-only servers production environment.
I was wondering initially, also under suggestion of some colleagues, to
stick with a cron-scripted solution, since they had the impression that
Amanda would just over complicate everything.
Anyway this would require initial engineering time, like writing cron
scripts that would manage dump and tar utilities together mtx to manage
all the stuff. At this point in time, I'd rather go with a ready-to-go
solution like Amanda, even if initially we still would need some time to
spend on the configuration. Also, this will give us the fancy of
detailed email reports, that are always a good thing.
This is what we have to backup: 4 (four) production servers (2x
application & 2x database) full filesystems dump (/, /var, etc), and
some GFS filesystem stored on an iSCSI SAN, mounted as read-only on the
admin server, where Amanda server will be running.
We will use tape as backup medium, with a Dell PowerVault 124T attached
to the SCSI controller of the admin server. This tape library will be
capable of handling a total size of 6.4TB native uncompressed data with
2 magazines of 8 slots each using LTO-3 Ultrium 400GB cartridges.
While the local filesystems of all the servers would fit on a single
400GB cartridges (leaving most of the space free), I'm wondering how to
manager the backup of the GFS volumes. GFS infact doesn't have a "dump"
tool that dumps the filesystem at fs block level, that means that for
full and incremental backup the only way to go seems to be tar. This
will produce a lot of swapping on disks since tar uses to catalog all
the files before writing them. A less hw intensive tool would be cpio
but this will not handle incremental backups. I've also searched for
utilities dumping LVM2 volumes, or Volume Groups (since our GFS
filesystems are on top of them), but nothing exist. If you have some
suggestions here, or better alternatives, please let me know.
Other than this, I'm trying to figure out which is the best backup plan.
I'd go with a weekly full backup for everything (servers local
filesystems & GFS volumes) and an incremental daily. We will use 2
different tape sets, to export physically tape cartridges from the data
center every week for data safety.
What I'm a bit confused about is how to manage the tape cycles during
the week, and how to handle backup of big size filesystems (in our case
GFS). Actually the filesystem is of around 1TB, but I'm guessing if it
would be better to split it in different mountpoints, each of 400GB.
This would probably give some benefits for the backup, since this is the
exact size of our cartridges.
If I'm not wrong, this is what it should be done:
Monday 00:00 full servers filesystem dump into 1 cartridge; full GFS tar
into multiple tapes OR 1 cartridge for every single 400GB GFS filesystem
Tue-Sun 00:00 incremental dump of servers filesystem; incremental GFS
tar as above
The questions are:
- How many cartridges do I need?
- How cartridges should be rotated during the week?
- Is it possible to use a different set of tape for every week, e.g. two
sets to be rotated weekly using a full backup every monday?
- Is it better to split the GFS filesystem into multiple 400GB volumes
to improve the ease of backup?
Sorry for being stressful.. I would hoped to be more specific...
Kind regards,
Fabio
|
