RAID 1 solution for desktop

In article 1129351090.118109@smirk,
wrote:

And WAY more reliable. Yes, I know you have RAID-1. But I like belt
and suspenders. And you'll have less time spent on occasionally
(every few years) replacing disks.

SATA hasn't been in the field very long so it's a counterfeit claim to
say it is more reliable, let alone way more reliable.

Besides, if needed more space eventually, then you'd be replacing the
disks with larger ones every few years anyway.

Look at it this way: The cost of this workstation going down is
probably the salary (or lost productivity?) of the person using it.
At a cost of maybe $150K per year (with overhead and such) for the
user, that's $75 per hour. Compared to that, the extra cost of SCSI
is just a few hours less trouble.

What about the reliability of the whole system? Electronic components
fail and their failure rate is probably the highest of all.

One other related question: The onboard RAID on the MB(Asus P4C800
Deluxe) is the Promise PDC20378 controller chipset. From what I've read
in other forums, this is actually a software RAID controller, no?

I have a similar MB - Asus P5P800. Its onboard RAID is not software - it does
not load the CPU at all.

--
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation

http://www.storagecraft.com

"Bill Todd" wrote in message
news:HKKdnanyQMyZus3enZ2dnUVZ_s6dnZ2d@metrocastcab levision.com...
David Beasley wrote:
Bill Todd wrote:

In that case, you may actually be better off with the newest
high-density 7200 rpm SATA drives.


Oh, how so?

In transfer rate, of course: the context to which I was replying.

The highest-density new SATA drives rival or exceed anything else on the
market in this area, because while they spin more slowly their linear
density is high enough to compensate.

- bill

Bill,

you're way off.

The delivered data rate at outer diameter is 49.5KB/inch on Barracuda and
44.9KB/inch on Atlas
but the Atlas 15K needs more servo spokes, has more relocation space per
track
and has more ecc bits, the actual bit density down on the drive is about the
same.

The translates to a max sustained transfer rate on Atlas 15K II of 97.4
MB/s versus 69.8 MB/s
on Barracuda 7200.
( IOPS for the Atlas is max 401 IO/s versus 84 IO/s for Barracuda)
For a head to head comparison see
http://www.storagereview.com/php/ben...280&devCnt= 2

Thanks
Joe

Joseph Fagan wrote:
"Bill Todd" wrote in message
news:HKKdnanyQMyZus3enZ2dnUVZ_s6dnZ2d@metrocastcab levision.com...

David Beasley wrote:

Bill Todd wrote:


In that case, you may actually be better off with the newest
high-density 7200 rpm SATA drives.


Oh, how so?

In transfer rate, of course: the context to which I was replying.

The highest-density new SATA drives rival or exceed anything else on the
market in this area, because while they spin more slowly their linear
density is high enough to compensate.

- bill


Bill,

you're way off.

The delivered data rate at outer diameter is 49.5KB/inch on Barracuda and
44.9KB/inch on Atlas
but the Atlas 15K needs more servo spokes, has more relocation space per
track
and has more ecc bits, the actual bit density down on the drive is about the
same.

The translates to a max sustained transfer rate on Atlas 15K II of 97.4
MB/s versus 69.8 MB/s
on Barracuda 7200.

So it would seem. Either this relationship has changed over the past
couple of years, or my memory was faulty.

On the other hand, I would like to see rates for the new 160 GB
Barracuda, since it sports 160 GB per platter vs. only 133 GB per
platter for the version tested: if this translates to a higher linear
density (as some of the discussion at Storage Review seems to suggest)
then it could as much as halve the gap with the Atlas (it would still
lag noticeably but by a far less significant amount - and if you needed
more you could probably buy at least a half-dozen of the Barracudas for
the price of one Atlas and get 4x - 5x greater read-streaming
performance thereby, plus RAID-1 protection for free with all the extra
space you'd have, though that would cut your streaming write-performance
improvement to only 2x - 2.5x).

( IOPS for the Atlas is max 401 IO/s versus 84 IO/s for Barracuda)
For a head to head comparison see
http://www.storagereview.com/php/ben...280&devCnt= 2

While IOPS are not relevant to this discussion, it does seem a bit
disingenuous to compare a drive using command queuing against one which
has it disabled (as the Seagate drive does in this test, though why is
not clear). The base (no queuing) scores are what one would expect from
comparing average access times, save that there's something screwy with
the Barracuda's average write access time and its real base score should
probably be a bit over 70 IOPS (I'm guessing that it either had
write-verify enabled or was suffering from environmental vibration,
since it took just about an extra revolution to complete each write).
Had the Seagate drive's queuing facilities been enabled it presumably
would have improved with queue depth at a similar rate to the Maxtor (at
least up to whatever queue depth it supports, which the recent 7200.9
test suggests may be only 32 entries - plenty for real-world use, since
at that level average latency has risen to about 0.3 second; the slight
improvement that it did exhibit was likely due to driver software queue
optimization).

Thanks for introducing me to the Storage Review site: I'd heard about
it but never bothered to take much of a look. Aside from the fact that
they really should have run down that write-access timing problem with
the Barracuda 7200.8 (especially after it failed to reappear in their
7200.9 testing), they seem to provide some useful information.

- bill