Martin Nilsson wrote:
Artem Kuchin wrote:
Marc G. Fournier <[EMAIL PROTECTED]> wrote:
For the last 6 month i really think that if you don't need something
high-end scsi then you should go for SATA.
Fair enough if you don't need high-end yoy shuld go lowend. But read on..
There are test on sites such as
Tom's hardware guide and ixbt.com. They show then on sequrncial read
there is no difference between scsi and sata.
That is a well known fact. It is also a totally useless parameter for
server use.
Acatuallty, modern hdds use the same mechanics for sata and scsi
> versions of them. The brains
This is simply not true. There were a couple of drives about 10yrs ago
where this was true eg. Quantum Lightning which were available in both
IDE and SCSI
Todays SCSI drives have _nothing_ in common with SATA/ATA drives.
However, when it comes to random read/writesscsi wins because of
> command queueing.
And faster accesstime and higher rotational speed (lower latency) you
simply can't compare a 7200rpm drive to a 15000rpm drive no matter
what interface it has.
Recently SATA with NCQ became widly available. Test show that some of
those
SATA disks with NCW ***WIN*** over scsi 320.
To use NCQ drive, controller and OS needs to support it, only a few
controllers supports NCQ and FreeBSD have no support at all!
this brings up a very interesting question. for anyone who has read up
on the SATA-II (or SATA-IO, as it has been renamed...) standard... not
all SATA-II harddrives have to support NCQ, nor do they have to have the
3Gb/s transfer rate. now does this also mean that motherboards which
have SATA-II compliant chips don't have to support those features
either? how do you know you're actually getting these features? i
think perhaps the standard has been a little messed up since they
didn't force a set of standards to be included in a "SATA-II" drive...
The test envolve artificialy randomread/write tests as well as
> real application benchmarking. I din't rememeber where
excatly i saw the tests on those site, but you could search.
The tests on tomshardware are windows single user centric, they never
test server workloads, their audience are kids who plays games...
So, my opinion, workstation never needs SCSI and every server MUST be
on mirror or RAID5 and there you should use SATA with NCQ drivers
unless,
your applicaton is really weird and needs something extremely speedy.
Then, however,
you could go for RAID 0+1 and get perfomance that SCSI will never get
you.
Want something cheap with lots of space? SATA
Want something that works and is fast? SCSI
Using SATA for databases and mailservers is going to give you bad
performance.
Regards,
Martin
also, if anyone has read the reviews at anandtech.com there has been
lots of evidence that shows that, on certain operations, NCQ actually
performs worse in real world tests. with the Maxtor DiamondMax 10,
Seagate 7200.8 and several other NCQ drives, the NCQ caused lag in
certain disk operations. NCQ, at least for now, is highly over-rated.
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