[Pc_Support] Re: Backup methodology -- centralize for lower TCO

[Bryan J. Smith]

On Mon, 2006-06-26 at 16:39 -0400, Damien McKenna wrote:
> So should I do a daily backup to the local drive and then backup up  
> *that* data file to the tape?

You should always _avoid_ streaming over the network directly to tape.
  http://www.samag.com/documents/sam0509a/0509a_f1.htm  

At a minimum, you should only send _deltas_ to a near-line store, and
then back that up to tape:  
  http://www.samag.com/documents/sam0509a/0509a_f2.htm  

But in reality today, most people only need off-line backups (e.g.,
tape/off-site) every week or so.  At the same time, they still want
nightly near-line backups they can restore from quickly (e.g., disk).
Ironically the storage required for "near-line" is not much more than
"delta/buffer-only", because you're just adding a few more deltas.
  http://www.samag.com/documents/sam0509a/0509a_f3.htm  

You _never_ want the limitations of tape to "hold up" your backups or
prevent them from completing during the window.  At the same time you
recognize that near-line/on-site is not complete without
off-line/off-site.  And you really want to _avoid_ "manual overhead"
that just complicates and costs more -- especially when you can't find
something or things don't happen automatically.

> Or how would it work?  We use BackupExec 10 right now but aren't
> completely adversed to changing to something else, especially as
> our licenses are up for renewal anyway.

Veritas (now Symantec) NetBackup is the "enterprise" complement to their
BackupExec.  You only need 1 server license and then agents as needed
_if_ you use a _centralized_ backup server.

> Right now I'm thinking of an NLE drive in a Firewire enclosure - do  
> you think a Serial-ATA or e-SATA setup would be more reliable?

Er, um, er -- if you don't want to go tape, then at least go with 2.5"
drives.  They can take 10x as much shock as 3.5" drives.  Of course,
they'll cost you $100 for 60GB.

As far as FireWire v. SATA, it really depends.  FireWire is slower and
can have various issues, SATA is solid (and eSATA brackets/cables only
cost $10).  But the opposite is that you can't "plug'n play" eSATA (at
least not without a $100 3Ware 8006-2LP SATA card), so that becomes an
issue.

> We're not looking to spend too much on this so SCSI and SAS are out
> of the question.

First off, SAS is just SATA with SCSI-2.  You can still use SATA drives
on SAS cards.  In fact, many SAS drives fix the "plug'n play" issue of
SATA like 3Ware cards.

Secondly, I'm scratching my head on what you want.  You're already
looking to spend money on various disks, cards, etc... as well as
software licenses.

By the time you keep throwing superstore solutions at the problem,
you'll probably find that you're already spending $1-2K on a half-baked,
unmaintainable or unreliable system of disks, manual tasks, etc... --
not including the manual overhead to implement it.

Which is why ...

> What I'm aiming for is a weekly backup and then daily incremental  
> backups.  I'd like the tape backup to basically be a mirror of the on- 
> disc backup if possible (if it happens at the weekend its pretty much  
> guaranteed to be).

For how many systems are you backing up?

Remember, the more "portable disks" you have flying around the "more
systems to backup," the more manual overhead you have, various
procedures, etc... and lots and lots of room for error.  Plus it's not
really cheap to maintain several disks, let alone deal with their
failure, added vibration and other things flying around.

At some point, _centralizing_ your backup on your network is what you
want.  And if you're not doing that with a combination of disk and tape,
you're leaving holes in your backup strategy.  It doesn't cost much to
implement at all -- and backup should be the one place where you _want_
to spend a few thousand to ensure it is _manageable_!

Build a _dedicated_ backup server:  
- Put lots of disk on it
- Put a single tape drive on it

You can build a quality PCI-X/PCIe single or dual-core Opteron/Xeon with
2GB of RAM for $750 ...
  $200 mainboard
  $150 CPU (single-core, double for dual-core)
  $150 memory (non-ECC, double for ECC)
  $100 Ultra 160 SCSI card
  $150 quality case, PS, DVD-RAM/RW/R drive, various other items
Add $750 for 960GB of usable RAID-5 on a 3Ware Escalade 9550SX-4LP
(RAID-5 is fine, performance-wise, because you're reading from disk for
the tape stream) ...
  $300 3Ware Escalade 9550SX-4LP (PCI-X**)
  $450 (4) WD3200SD Caviar RE 24x7 rated Enterprise 320GB
Finally, add another $750 for a 100/200GB LTO-1 tape drive.

[**NOTE:  3Ware has added a new 9590SX series that is PCIe.  It seems to
be the 9550SX with a PCI-X to PCIe bridge, so it might work just fine.
But I haven't tried it personally.  BTW, the 9550SX products seem to be
the best for 4+ channels now -- the firmware issues all shaken out. ]

Then you basically:  
- Do a full backup of every system you want backed up
- Then delta all systems every night

After that you have full copies of everything.  If your backup software
is "smart," it can maintain those multiple "deltas" (like snapshots) and
let you restore from select points in time -- right from disk, over the
network.

At the same time, you can put whatever you want to tape, directly from
that centralized backup server.  You don't have to slam you network with
traffic.  The _only_ traffic on your network are those _small_,
_incremental_ deltas that occur at night from the servers/workstations
to the backup server.


-- 
Bryan J. Smith           Professional, technical annoyance
mailto:b.j.smith at ieee.org     http://thebs413.blogspot.com
----------------------------------------------------------
The existence of Linux has far more to do with the breakup
of AT&T's monopoly than anything Microsoft has ever done.