| > 8530 - VAXBI bus
> 6310 - XMI bus<------DEMFA my guess?
> 4000 mdl 300 - QBUS
> Apparently there is an FDDI controller for the 6000 platform. Is
> there something for the other two? Network backups over standard
> ethernet is now taking tooooooooooooo long. Going to TF857 on the
The VAX 6300 series is very slow. FDDI will not help much there.
The VAX 4000-300 and 8530 have comparable speed, as I recall.
Given that DEC 5000/200 attains in the ballpark of 20 Mbit/sec over
FDDI for simple file transfers (not with error coding as in BACKUP),
I would think that VAX 4000-300 and 8530 will do no better.
So, if you *could* buy FDDI interfaces for those machines, the
performance boost will be under 100% compared to Ethernet. Perhaps
the money is better spent getting faster CPUs. Or, use DSSI clustering
for really fast backup (if you have VAXcluster licenses for this stuff).
Finally, make sure that the Ethernet is running at peak performance
(no competition with other heavy traffic during the backups).
Moral: CI and DSSI can be fast even for slow CPUs. FDDI is almost as
slow as Ethernet when used on a CPU that has only "2 x Ethernet" power.
If you had a VAX 6440 instead of 8530, then driving FDDI at full speed
is more practical.
|