Intro
The fastest traditional hard drives (regular, fast SCSI-2 narrow) we know of
are the IBM Ultrastar 4GB 3.5" drives. They easily sustain transfer rates of
4.5MB/sec off the inner sectors. They are slightly faster than the Micropolis
and Seagate 4GB products, in that order. 4GB is now the smallest we deal with,
so I don't have any numbers on the smaller drives. I'm positive they're
slower, though.
btw- Seagate has a "two-head" product in the 2GB capacity range which is even
faster – but it's a lot more expensive, especially per GB.
Arrays can be really confusing. Maximum performance can be limited by whatever
SCSI bus you're on, and quite a few companies make products which can almost
pin that. For example, take a wide SCSI bus and two of the aforemetioned
narrow IBM drives and use any of a number of vendors' software to stripe the
drives (technically not RAID but called RAID Level 0 by many) and you can bump
performance up to the 8-9MB/sec range (on a wide bus). Now swap out those
narrow drives and substitute two WIDE Ultrastar drives and you will see between
12 and 15MB/sec SUSTAINED. Burst data transfers from a pair of these drives or
a pair of the 2-head Seagate's or the Seagate Elite-9 (9GB drive) seem to be
clipped at around 17.3 MB/sec leading us to conclude initially that we are
hitting the practical limit of Wide SCSI.
There are additionally a number of hardware-based RAID solutions which have
varying levels of performance and added features at the various levels, most
notably data redundancy or parity. But none of these solutions will
meaningfully outperform two or three software striped drives – at least in our
application, unless you get really fancy (and expensive).
Having said all this – please take note: if the rest of the system (SCSI bus
host adapter, codec, internal cpu bus and memory management system) can't
handle that data rate – screaming storage doesn't do you any good TODAY.
Nonetheless, I have a recommendation that I always give Avid storage customers.
Do not buy a single MB of storage today, unless you absolutely need it. Then
and only then, buy the fastest, largest thing you can. That is the only way,
until our industry matures, that you can maximize the useful life of the
product before the inexorable technology curve trys to obsolete it. And as it
becomes obsolete, it is not reasonable to expect the vendor to somehow take it
back or upgrade it. So protect yourself as much as possible and then just
accept the nature of this fascinating industry.
I hope that helps.