[Gllug] Advice on backup options

Rev Simon Rumble simon at rumble.net
Wed Jul 7 14:28:14 UTC 2004

Hi folks.

I do volunteer computer work for a non-profit organisation called
Peaceworkers UK.  (Contact me privately if you're interested in
helping.)  They're looking to upgrade the hard drive on their
(e-smith/SME Server -- www.contribs.org) server and need to upgrade
their (already not particularly great) backup system to match.

Backup is one of those things where experience counts for a lot, and I
don't have much.  You only get one shot at getting it right, so I'd
like to ask your opinion.  1 f34r y0ur l33t b4ckup 5k1ll5

Please comment on the options in the draft below.  Prices are from
scan.co.uk -- if you know cheaper or better options, let me know.  All
suggestions considered.

As with all non-profits, price is VERY critical.  They don't even have
any budget for IT left this year, and will have to dip into other pots
to fund this.



Peaceworkers backup and upgrade options

Peaceworkers require an upgrade to the storage space of the e-smith
server.  I recommend the following, assuming 40 gigabytes is enough
storage space.

40Gb Maxtor Plus 8 ATA-133 (7200rpm, 2MB) £31.63

Extra storage space brings with it the problem of data backup.  In the
commercial sector, tape backups provide the best balance of removable
storage and low media costs.  The problem is that the startup costs
are enormous.  An entry-level tape drive costs in excess of £300.  The
tapes to feed into the drive thereafter, however, are very cheap.

This price is probably out of the range of Peaceworkers' budget,
although it is worth considering as the rock-solid dependable option
that will last for years.

Backup is designed for two different types of data disaster.  The most
common is a hard disk crash, where the finite-lifespan of the moving
disk platter comes to an end, which is unpredictable.  The other is
the business-continuity problems of major disasters fire, flood,
nuclear holocaust etc.

The key features of any data backup system are:

* Off-site: at least one copy of the data must reside in another
  physical location at all times. 
* Verifiable: the backup/restore system must be tested and able to be
  verified that an actual restorable copy is accurately written every
* Restorable: parts of the data can be quickly and easily restored
  from backup in the event of accidental damage (delete, overwrite,
  etc) to individual files.
* Disaster Recovery: the data can be restored using standard,
  off-the-shelf equipment in the case of complete loss of original
  equipment, and the possibility that it may be restored on a
  completely different system and operating system.
* Secure: the data must be secure from external eavesdropping at the
  remote site.
* Complete: ideally, the data is written in its entirety to a single
  unit, rather than spanning several.

Below I have outlined some options and their prices, in descending
order of preference.

External hard drives

Two external hard drives are purchased. On a rotational basis, where
one of the drives is always off-site, a hard drive is brought in and
the data copied.  The hard drives must be at least the same capacity
as the full disk size on the server.

40Gb Freecom Classic SL 3.5" Slim Line USB2 (5400rpm,2MB,11ms) @£65.51
X2 = £131.02
USB2 interface card for server approx. @£10.00

Total approximate cost: £140

Pros: Always one copy of data off-site.  Quick backups.  Backups can
be daily.  Allowance for user forgetting to take drive away.
Cons: Users must be disciplined with rotation.


DVD backups are taken on a periodic basis.  DVD+R DL format allows 8.5
gigabytes, which means about five disks per complete backup.

NEC 2510 OEM Ivory DUAL LAYER DVD-Writer (Dual Layer +R 2.4x, DVD+-
x8, RW+-x4) @£56.11
Media cost = approximately £0.50 each

Pros: Cheap up-front costs.
Cons: Media costs mount quite quickly (one full backup a week =
£130/year). Someone has to feed the disks into the drive.  Daily
backups are not feasible.

External hard drive

A single external hard drive is used for backup, as above, and taken
off-site at the end of the day.

40Gb Freecom Classic SL 3.5" Slim Line USB2 (5400rpm,2MB,11ms) @£65.51
USB2 interface card for server approx. @£10.00

Pros: Cheap and easy.  Backups can be daily.
Cons: Original and backup copies of data are on-site during the day.
No allowance for user forgetting to take the backup drive away.

Backup "swap" with another organisation

Peaceworkers and freesolutions work with another organisation on
another site to backup over the Internet onto that organisation's
system in the early hours of the morning.  Peaceworkers could offer to
host that organisation's backups using the same method in return.

40Gb Maxtor Plus 8 ATA-133 (7200rpm, 2MB) £31.63

Pros: Very cheap.
Cons: Requires trustworthy, knowledgable remote administrators.
Bandwidth limits imposed by ISP (if applicable).  No known
organisation that fits the bill yet.

SAN device in fireproof safe

A network-storage device is located in as seperate a wing of the
building as possible, in a fireproof safe.

Ximeta Portable NetDisk 80Gb £89.30

Pros: Cheap, quick, accessible.
Cons: Not off-site!  Allows for certain types of fires only.  Does not
allow for other types of disaster.

Machine in my home

A low-end scavanged machine is located in my house and backups occur
over the Internet to that machine.

40Gb Maxtor Plus 8 ATA-133 (7200rpm, 2MB) £31.63

Pros: Very cheap.
Cons: Could send my bandwidth over its daily 1 gigabyte limit.  Not
necessarily reliable.

Mirrored hard disk in server

A second, identical hard disk is placed in the machine.  Data is
mirrored across both drives.  This setup is recommended, even with
other backup systems, to account for the most common data disaster of
hard disk failure.

40Gb Maxtor Plus 8 ATA-133 (7200rpm, 2MB) £31.63

Pros: Very cheap.  Allows for instant recovery from hard disk
Cons: "Backup" is in same box as server.  Not a real "backup"

----- End forwarded message -----

Rev Simon Rumble <simon at rumble.net>

 "The ability to quote is a serviceable substitute for wit."
- Somerset Maugham
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