Andrew Lentvorski wrote: > Yes, and one controller and cable per disk is a *good* thing. > > For example, a hot swap failure won't take down the entire chain. A > terminator failure won't take down the entire chain. A cable ground > fault won't fry multiple drives.
That is a very good point which I had not considered before. I am pretty sure I have seen a device error take down a whole chain. I also very much like the fact that the small serial ATA cables decrease airflow blackage much less than the ribbon cables. And when wiring up two drives on an PATA ribbon cable it always seemed like I had to put an awkward twist in the cable to make the connectors line up right. Very annoying. The decreased airflow blockage is very important in a 1u case. I saw a case in our datacenter the other day that had a ribbon cable laying flat up against the front of the intake vents of a 1u case. I should probably have something done about that. > Try here for starters: > http://www.sata-io.org/docs/SATA%20Enterprise%20WP.pdf Very interesting. Serial-attached SCSI. I hadn't heard of that before but it makes sense. Why didn't we go to these serial technologies sooner? I am guessing the signal processing capabilities did not exist. > Also, serial-attached SCSI seems to be the development path of the > future. So, SCSI is going to lose drive to drive. The enterprise folks > don't seem to be bothered too much by that. Personally, I agree with > them. I would rather see the drive to drive transfers handled by my > controller card rather than stuck into the drive. That way I get the > best performance my *card* supports rather than being stuck with the > worst performance of all of my drives. Indeed. At MP3 I was looking for a way to do direct drive to disk backups over fibrechannel SAN but nobody supported it and still don't afaik. >> Are these for comparable hardware? Another one of the web-pages >> asserted that (Enterprise-class? Server-class?) SCSI drives have >> stronger arms and better motors and suchlike, to better handle >> server-class loads. > > That is true. SCSI drives need stronger motors for 15K RPM drives and > they up the seek servos to match. I have heard for years that SCSI drives get the platters and drive heads that QA'd higher or some such thing. I have always wondered if that was true. I am skeptical. But even if SCSI is more reliable it can't be by that much and my plan is to use the saved money (SATA saves lots of SCSI) and buy more hot spares. -- Tracy R Reed http://copilotconsulting.com 1-877-MY-COPILOT -- [email protected] http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
