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sas - SCSI vs SATA? Is SCSI "actually" better?





Well, I was talking with a guy about servers the other day. I was a
bit shocked whenever I asked him if there was any significant difference between SCSI
and SATA and why he always uses SCSI. (note, I'm not sure if by SCSI he meant
SAS)



He told me that SCSI is always faster and
that the drives are always more reliable.. I mean, this seems like a bold statement.



He told me something about how SCSI will always
be faster than SATA because the OS sends the SCSI (controller?) a request to get a file
and it will build the file inside of the SCSI controller, instead of searching all over
the disk.. which I do not understand how that would work, so I figure it is
BS.



SAS and SATA currently have equivalent data
rate speeds..




Is there
any true backing for his reasoning that SCSI is always faster and more reliable than
SATA?


itemprop="text">
class="normal">Answer



For SATA,
you need to be careful about using a consumer drive if you are building a RAID
array.



Some power saving features and in the
case of Western Digital, some of their SATA drives have a "deep recovery" process when
an error is detected. These can cause a SATA RAID member to be dropped or marked as
failed if it is unresponsive beyond the timeout
period.



When a SATA RAID5 volume with huge
drives drops a member, it is not uncommon for the rebuild to take several hours. During
this time, performance will be
abysmal.



Western Digital -
difference between Desktop edition and RAID (Enterprise) edition hard
drives?

href="http://wdc.custhelp.com/cgi-bin/wdc.cfg/php/enduser/std_adp.php?p_faqid=1397"
rel="nofollow
noreferrer">http://wdc.custhelp.com/cgi-bin/wdc.cfg/php/enduser/std_adp.php?p_faqid=1397



href="http://en.wikipedia.org/wiki/Time-Limited_Error_Recovery" rel="nofollow
noreferrer">http://en.wikipedia.org/wiki/Time-Limited_Error_Recovery


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