Re: HD Backup

["Bryan J. Smith" <b.j.smith@ieee.org>]

Ray Holtz <ray@rayholtz.com> wrote:
> Anywho, I’ve got a client on the side up here who wants to
> backup the Linux (Fedora 4) file server I setup for him.
> I’m thinking of doing an external hard drive backup and
just
> writing a script to copy all the file shares to the
external
> HD so he can move that off-site very easily.  What I’m
> looking for here is recommendations of external HD that
> are good brands, breath easily (so it doesn’t overheat),
> is USB2, and not too hefty of a price tag hopefully.

With kernel 2.6, hotplug is now included.  So I highly
recommend you consider a hot-swap SATA drive.  SATA (as well
as SAS, Serial Attached SCSI, which uses the same connectors)
has staggered power/data connectors for complete electrical
transient.  So the only remaining issue is software, which
hotplug in 2.6 handles.

USB and FireWire are real reliability PITAs under Linux,
MacOS X and even Windows XP -- plus USB 2.0 has the
additional requirement that you must plug it into a port that
is connected to an EHCI -- which is typically a _minority_ of
your USB ports.  And even then, they are both significantly
slower than SATA or SAS.

> Currently he has less than 20GB that need to be backed up,
so
> even a ‘small’ 100GB drive would give him a about 5 weeks
of
> backups per drive.

Then consider a 2.5" notebook SATA drive instead of a 3.5". 
They can take an _order_ of _magnitude_ greater shock, and
are designed for non-daily use (whereas commodity 3.5" is
designed for daily upon first use).  A 40GB 2.5" notebook
drive can be had for $60 these days, $90 for SATA.  I really
recommend the SATA version for the staggered pins.

If cost is a concern, you can mount a 2.5" notebook SATA
drive in a 3.5" SATA hotswap bay -- cabling is identical. 
You can also use rubber standoffs to improve shock tolerance.

If you really don't want to go the 2.5" route, then pay the
extra $20-40 for a "near-line, 24x7 rated" version of a
commodity 3.5" drive.  This is the Seagate NL35 (enterprise
version of the Seagate Barracuda ATA 7200.8), Western Digital
Caviar RE/RE2 (enterprise version of the Western Digital
Caviar SE 8/16MB), etc...

> I’m thinking of setting him up with 3 drives, so a
> backup Mon, Wed, and Fri nights.

Yes, don't put all your eggs in 1 basket.

> Also if anyone has any creative ways of writing such a
> script to copy the files, I’d love to hear about that too!

rsync does everything you want, even for local copying.

Also consider a remote "rsync" over "ssh" to a Windows
system, which is backed up.  Using rsync means the only time
you ahve signficant load is the first time it run -- it's
only diffs from then on.  Use "getfacl -R" to preserve both
traditional and POSIX ACLs in a file, which you can then
reapply with "setfacl --restore".

Of course, storing some UNIX special nodes on a Windows
filesystem can be an issue.  So I often use "afio" piped over
"ssh" -- although that means I'm doing full backups, or
incrementals from a date in my scripts (whereas rsync is much
easier).

In an ideal world, you should have a dedicated Linux
near-line server with 4x as much storage as you need to
backup in total on your network (including all Windows
systems), that has several volumes of your last 1-2 weeks of
backup.  You only do diff's from each system during your
backup window, and the local system handles all the "virtual
volume" management of backups.  It should also then have a
tape drive to off-line data for disaster recovery -- 100GB,
20MBps "native" (2x for compression) LTO-1 drives start at
well under $1,000, and the 100/200GB tapes are only $25/each.

> Something simple like Bash Scripting that I can follow,
> and edit when necessary. I’m thinking of something where it
> checks for backups that are older than 4 or 5 weeks,
> deletes those to open up space,

The find "mtime" option will help you there.

> then copies the files and folders it needs.   I’m not
asking
> for anyone to do my work for me, but to point me in the
right
> direction or maybe any resources I can check online to
create
> this.

The find command does a lot of what you need.

Otherwise, I really like afio for a streaming backup program
-- with per-file compression inside of the archive.  It's far
more tolerant of errors than tar/cpio which are compressed
whole.

> Also also, what are anyone’s thoughts on formatting the
> drives with FAT32 so that if need be, the drive and its
files
> can be read by a Windows computer?

Er, um, not ideal.  I'd use UDF (Universal Device Format) if
anything.  NTFS isn't an option because it's not designed for
removable.  FAT32 is too shaky.

If you don't use Ext2/3, be sure to use "getfacl -R" to
preserve all traditional UNIX and POSIX ACLs.  Of course,
this doesn't backup your other Extended Attributes (EAs) like
SELinux, if you are enforcing them.  The latest e2fsdump
supposedly backups up all EAs, but I'll believe it when I see
it (until then, I only trust XFS and its xfsdump -- although
not as of late in Linux because of how XFS' development has
gone, long story).



-- 
Bryan J. Smith     Professional, Technical Annoyance                      b.j.smith@ieee.org      http://thebs413.blogspot.com
----------------------------------------------------
*** Speed doesn't kill, difference in speed does ***

-
To unsubscribe, send email to majordomo@silug.org with
"unsubscribe silug-discuss" in the body.