On Fri, 26 Jan 2007, Anton B. Rang wrote:
> > > How badly can you mess up a JBOD?
> >
> > Two words: vibration, cooling.
>
> Three more: power, signal quality.
>
> I've seen even individual drive cases with bad enough signal quality to cause
> bit errors.
Yes - me too. I was a early adopter of Fibre Channel, and the first FC
enclosure I had the misfortune to purchase, had really terrible signal
quality and noise issues. It took me awhile to figure out if it was the
beta drivers, brand new FC HBA, copper wiring, Seagate disk drives or ....
The breakthrough came when I got a simple FC interface board (from
Seagate[0]) that had a 3ft FC (copper) cable and could be plugged directly
into a FC disk drive. At that point I knew that everything was solid,
from computer system to the disk drive, and because the same drive would
not perform in the FC enclosure - it was obvious where the problem lay.
Looking inside the enclosure, it was wired, point-to-point, with cables
and connectors that closely resemble the cable/connector you see that
carries the digital audio from a CD-ROM to a PC motherboard. It was
pretty obvious that the company who built this enclosure (they manufacture
a bunch of disk drive enclosures - many as OEM products) did'nt realize
that they were now dealing with microwave signals and needed RF (Radio
Frequency) expertize in order to design a solid FC enclosure.
[0] it was intended for disk drive trouble-shooting/testing etc and is
still very useful if you "play" with FC disk drives.
Regards,
Al Hopper Logical Approach Inc, Plano, TX. [EMAIL PROTECTED]
Voice: 972.379.2133 Fax: 972.379.2134 Timezone: US CDT
OpenSolaris.Org Community Advisory Board (CAB) Member - Apr 2005
OpenSolaris Governing Board (OGB) Member - Feb 2006
_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
