[NTLUG:Discuss] SCSI performance question

[Daniel Hauck]

Daniel Hauck さんは書きました:
> Leroy Tennison さんは書きました:
>> Robert Parkhurst wrote:
>>> I've used SCSI a lot, but mostly in the "lower-end" area (external CD/DVD
>>> SCSI drives, external SCSI hard drive or even a small SCSI external disk
>>> pack).  I'm curious though how SCSI would perform if you had a lot of large
>>> disk arrays attached off a single SCSI bus/adapter?
>>>
>>> Specifically, say I had an LSI SCSI adapter (Ultra-320, PCI-e (x8)) that
>>> could have 32 SCSI devices attached to it.  And I attached 31x16TB external
>>> SCSI enclosures (like the JetStor SCSI unit or something) off that one
>>> adapter and then used Linux to make an LVM striped volume over all of them
>>> and formatted it with something like ReiserFS or XFS.  Would I see a
>>> (noticeable) performance hit on it?
>>>
>>> And if so, what's a good "recommended" max for attaching storage like that
>>> to a single SCSI controller?
>>>
>>>
>>>
>>>
>>> Thanks in advance!
>>>
>>>
>>> Robert
>>> _______________________________________________
>>> http://www.ntlug.org/mailman/listinfo/discuss
>>>
>> This is almost impossible to answer because performance is affected by
>> too many variables: what are the capabilities of the SCSI controller
>> (caching and how much? is the firmware efficient? how many channels?
>> other performance characteristics), the SCSI drives (all the common hard
>> drive performance characteristics), how is it configured (RAID?  If so,
>> which level?) and what your application is (mainly read-only, lots of
>> writing, lots of deletions after writing, a database).  Further
>> complicating matters is the fact that it's not just individual issues
>> but combinations of them (matching the configuration and the hardware to
>> the application).
>>
> 
> Well I think since you are living just over 3 months into the future,
> you can tell us what the ultimate solution to the problem was.
> 
> Oh, by the way, you are aware that your system's clock is set wrong yes?
> 
> _______________________________________________
> http://www.ntlug.org/mailman/listinfo/discuss
> 
Whoops!  I had my email sorted by date/time of the email and not by
date/time of arrival.  That happened long ago.  Nevermind!  (And here I
thought I was being clever)