marc@Apple.COM (Mark Dawson) (12/07/89)
Our department is considering purchasing an optical drive for backup (we have between 500-600mb of servers to backup) and to use the various CD products now comming out. What are your experiences using opticals (write-once or the newer read/write)? Do you have any recommendations? Thanks --Mark
herbw@midas.WR.TEK.COM (Herb Weiner) (12/08/89)
I use a WORM drive (Pioneer 600 MB from Corel) with DiskFit (version 1.4).
I use it to back up a 300 MB Hard disk containing approximately 180 MB.
Normally I back up once or twice per week, with a range of 1 MB to 4 MB
of changed files backed up each time.
For my needs, this is the IDEAL backup solution.
Advantages:
1. The Corel WORM Driver allows me to mount my disk (read only) as it
existed at any prior point in time. If my hard disk is ever infected
by a virus, or if I accidentally delete or screw up a file, or ...
I can get back my data, even if I have to go back to last year.
2. It's fast. Only changed data is backed up.
3. It uses cartridges efficiently. Only changed data is backed up.
If, for example, your hard disk holds 200 MB and you change 2 MB
per week, you can hold a year's worth of backup on one side of a
600 MB (300 MB per side) cartridge (200 MB + 50 * 2 MB). However,
the VIRTUAL capacity of the cartridge (for this example) is 10,000 MB!
(50 * 200 MB).
4. It's safe. Because it's write once, I can't accidentally delete files
from my backup. Even a virus can't infect files on my backup (although
it can create a new version of a file and infect the new version.)
Disadvantages:
1. Size of WORM drive must be correctly matched with size of hard disk and
rate of change of files. For example, if my hard disk had 300 MB of
data, a single backup would fill the cartridge, and I would not get
the benefit of advantage #3 above. Note that DiskFit COULD be enhanced
to support WORM drives by requesting a new cartridge (or the other side
of the same cartridge), but DiskFit does not currently (as of version
1.4) support this approach. (In MY opinion -- no flames please --
DiskFit's approach of deleting out of date versions makes it unacceptable
TO ME for backing up to anything OTHER than a WORM.)
2. DiskFit does not generate a report showing what files were backed up,
although you can see their names flash by on the screen. (Note, I use
Disk Duplicate rather than Backup.)
3. The WORM cartridges are somewhat fragile -- you are warned, for example,
not to drop them or subject them to shock. I hope to never discover
HOW sensitive, so I do not know whether this is paranoia or a real
concern.
Herb Weiner (herbw@midas.WR.TEK.COM)