Killer SCSI 1 TB fileserver

Bill Broadley bill at math.ucdavis.edu
Wed Oct 24 14:49:14 EDT 2001


On Wed, Oct 24, 2001 at 06:17:25AM -0400, Patrick Geoffray wrote:
> That's very interesting, I was looking yesterday at the 
> InfoStation: looks nice but a little bit expensive. 
> Can you comment your choice for the DS-500 ? How much did 
> you pay for it ?

It's about $1k.  I'd say it's just about perfect, considering I spent
$12k on the disks I wasn't worried about the enclosure price to much.

Does the infostation handle 4 scsi channels?  Does it have a redundant
power supply?  Good airflow?  Cable access?  Good build quality?
Temperature alarms? Fan alarms? Powersupply failure (1 of 2) alarms?
URL?

> > Adaptec 39160 in a 64 bit pci slot of a tyan thunder motherboard.
> > Raid-0 performance: (114 MB/sec write, 130 MB/sec read)
> 
> The CPU load seems very high: this is RAID software only ? 

Yes.  Although since the fileserver has 2 1.2 Ghz athlons in it,
not like there is much else for them to do.  So at 75% of
1 cpu the fileserver is mostly idle, and sustaining a level of
performance I am very happy with.  I guess if I had a magic
raid 5 card that could sustain similar with the cpu's idle
I could use it as a compute node, that wasn't part of my
design though.

> Your experience compared to RAID hardware ? I was unable to find 

Faster, more reliable, easier to manage.  I'd much prefer to have
a cron job that checks /proc/mdstat and use raid add/remove and 
similar then learn the interface of the week for binary tool
collection of the week from the vendor of the week.

My previous software raid-5 server (8 disk scsi) was up for over 400 
days without a single error, dmesg, or complaint of any kind.  It
replaced a much more expensive hardware solution that had 1/4th
the performance (using the same disks).

> a hardware RAID controller able to sustain 100+ MB/s RAID5, 
> but I didn't test a lot of them.

I've found none in anywhere around the same catagory that are able
to come close to the software raid numbers.  If you find something
please post your findings.

> > BTW I did build a 3ware 6800 + 8 EIDE configuration that was a complete
> > failure, numerous crashes, multiple filesystems lost, very unsatifactory
> 
> Idem. Our 6800 + 8 Quantum IDE was finaly replaced by 29160 + 4 IBMs. 
> The 6800 was resetting each 15 secondes under heavy load, and it would 
> take 2-3 secondes to re-initialize. It was a pain.
> The IDE disks have been recycled, and the 6800 is sitting on the floor 
> in a corner. 

Very similar to our experience.

> I wouldn't like to start an inventory thread here, but I cannot 
> find a U160 disk that is clearly the best choice, the best ratio 
> cost/perf. IBM's UltraStar looks fine, but Seagate and Fujitsu 
> are in the same playground. Do the people on the list have a 
> prefered Champion ? If so which one ?

Seagate makes the only 1" high 73 GB scsi disk that I know of.  IBM
announced similar but AFAIK they aren't shipping.  Most 73's at 1.6"
and won't fit in the hotswap carriers.

--
Bill Broadley
Institute of Theoretical Dynamics
University of California, Davis

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