Doug Ambrisko wrote:
Kip Macy writes:
|
| The interface is not the same - can one buy an adapter?
True that technically the interface is not the same. The SAS connector
spans the power supply and data port. SATA has separate data and
power. However, the mechanical spacing is the same except the SAS
drive does not have the gap to fit a separate power cable and separate
data cable. I've stuck several SATA drives in a SAS backplane
enclosure and Adaptec fan out cable. The mechanical interface
precludes a SAS driver plugged into a SATA controller but the
converse is not true.
The bridge between the two connectors on SAS holds the pins for the
second data channel that SAS supports. At a pure electrical and
signaling level, the primary channel on SAS is compatible with the
single channel on SATA. But for many technical and non-technical
reasons, it's possible to plug a SATA disk into a SAS
connector/controller, but not the other way around.
Do you have a SATA drive to try? I've even mixed a SAS and SATA
drives on the same controller at the same time. I know a few
people using SATA on a SAS controller since SAS drives are harder
to come by.
One of the promises of SAS was that you could combine the benefit of SAS
infrastructure (multipathing, channel bonding, and out-of-the-box
connectivity) with the cost effectiveness of SATA. Of course, that
already existed with Fibre Channel, so the migration to SAS hasn't been
as swift as many had hoped.
Now Dell doesn't recommend mixing types but I've done it to
do some testing.
Even though SATA and SAS are compatible at an electrical level,
there is quite a bit of magic involved in making a SAS controller
talk to a SATA disk. My guess is that Dell doesn't want you
adding too many magic variables to the mix on such new technology.
There is no adapter needed :-)
I wish there was a SCSI drive to SAS interface like PATA drive to
SATA. Unfortunately my PATA adapter is not compliant and won't
just work with a SAS cable :-(
I suppose that a PATA drive should work on a SAS controller if a SATA
converter is used. It's also possible to put a Chevy Nova drive train
into an Audi, given enough effort with a welding torch. I just wouldn't
recommend it.
Scott
_______________________________________________
cvs-all@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/cvs-all
To unsubscribe, send any mail to "[EMAIL PROTECTED]"
