Hot Diggety! Johnson, Milton was rumored to have written:
> I got a call from a rep asking if I was interested in a Sepaton S2100
> VTL (Virtual Tape Library) (www.sepaton.com). It's billed as:
> My questions include where's the down side? What's the catch? If your
> choice is between expanding by purchasing a second 3494 frame or a S2100
> VTL, why choose a 3494 frame?
Keep this rep honest -- ask him/her what the down sides (negatives) are,
what the typical failure modes are, and so forth.
You'll soon know if you're about to drink sugary Kool-Aid or not :-)
Well, simply put, I haven't heard of VTLs as a single source replacement
for tape drives per se. They are pretty good when you can't wait a
single second longer (or 2-3 minutes) for a restore to begin -- compare
disk vs tape restore load-to-ready time.
Lots of places has this kind of rapid restore requirements -- financial
firms (banks, Wall St, etc), hospitals, nuclear power plants, utilities,
and other places where any sort of downtime is extraordinarily bad.
However, I don't think disks yet have the long-term reliability that
tape drives do... well, server class SCSI drives *can* usually last 5
years in brutal 24x7 operation, but drives in general aren't too
tolerant of being underutilized or if it's the cheaper engineered hard
drives (e.g. typical IDE drives), overly utilized.
So the way I see VTLs as being most useful is if you can't wait the 2-3
minutes it takes to load+spool a tape to 'ready to peel data off'; it's
still no replacement for any serious archiving past perhaps 12 months or
so, and still needs another backup source to restore data from in case a
drive goes south and loses the data.
Modern tape drives are pretty zippy, too, at 70 MB/sec, don't forget.
Tapes (not tape drives) also contains far fewer moving parts that can
fail than hard drives which has a motor, PSU, depending on the sub-1mm
air gap (Bernoulli effect), etc.
VTLs has a place, in my honest opinion, but only if you've got the need
and only if it isn't the sole source for backup data. I don't think most
folks has this need; so it just seems like a big push for companies to
make money at your expense, unnecessarily (unless you actually do have a
need and a well-engineered overall setup). After coming off rough
economic times, you can expect lots of these pitches. :-) I've already
gotten two of these so far. :)