Q on sata disks

serge <serge_mtu.TakeThisOut@mtu-net.ru> wrote:
> I wonder if sata disks realy perform well?

SATA hard disks tend, in real-world situations (which often bear
vanishingly little relationship to benchmarks), to be bottlenecked by
physical I/O, same as PATA and SCSI ones. Of course, newer SATA drives
will tend to have better raw speed specs, but then, so will newer models
of the other types. This is no accident: Often, the same drive
mechanism will be sold as both ATA and SCSI depending only on the
interface board snapped onto each individual unit.

> Does the latest 2.6 kernel have full support for sata?

About as full as is available with anything else -- but there are
always new, as-yet-unsupported chipsets. My information page:

"Serial ATA" on http://linuxmafia.com/kb/Hardware/

In comp.os.linux.hardware serge <serge_mtu.DeleteThis@mtu-net.ru>:
> I wonder if sata disks realy perform well?
> I'd like to have a look upon Hdparm -t,

/dev/sda:
Timing buffered disk reads: 164 MB in 3.00 seconds = 54.59 MB/sec

Hdparm doesn't tell much, if doing real I/O on some cheapo IDE
stuff, you'll mention soon, what a good SATA/SCSI controller can
do for you.

> The disk model and the card

tw_cli info c0 p0 model
/c0/p0 Model = ST380013AS [Seagate]

tw_cli info c0 model
/c0 Model = 8006-2LP [3ware]

> Does the latest 2.6 kernel have full support for sata?

For the above 3ware controller, yep.

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serge wrote:

> I wonder if sata disks realy perform well?
> I'd like to have a look upon Hdparm -t,

# hdparm -t /dev/sda

/dev/sda:
Timing buffered disk reads: 166 MB in 3.02 seconds = 55.01 MB/sec

> The disk model and the card

Samsung SP1614C, Silicon Image SiI 3112

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Markku Kolkka
markku.kolkka.TakeThisOut@iki.fi

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you wrote:

*Often, the same drive
mechanism will be sold as both ATA and SCSI depending only on the
interface board snapped onto each individual unit.*

which one?

thank you



"Rick Moen" <rick RemoveThis @linuxmafia.com> ÓÏÏÂÝÉÌ/ÓÏÏÂÝÉÌÁ × ÎÏ×ÏÓÔÑÈ ÓÌÅÄÕÀÝÅÅ:
news:4105a$4337576e$c690c3ba$20217@TSOFT.COM...
> serge <serge_mtu RemoveThis @mtu-net.ru> wrote:
>> I wonder if sata disks realy perform well?
>
> SATA hard disks tend, in real-world situations (which often bear
> vanishingly little relationship to benchmarks), to be bottlenecked by
> physical I/O, same as PATA and SCSI ones. Of course, newer SATA drives
> will tend to have better raw speed specs, but then, so will newer models
> of the other types. This is no accident: Often, the same drive
> mechanism will be sold as both ATA and SCSI depending only on the
> interface board snapped onto each individual unit.
>
>> Does the latest 2.6 kernel have full support for sata?
>
> About as full as is available with anything else -- but there are
> always new, as-yet-unsupported chipsets. My information page:
>
> "Serial ATA" on http://linuxmafia.com/kb/Hardware/
>

serge <serge_mtu DeleteThis @mtu-net.ru> wrote:

> *Often, the same drive mechanism will be sold as both ATA and SCSI
> depending only on the interface board snapped onto each individual
> unit.*
>
> which one?

<sigh>

I'd have to spend time researching the current offerings from hard drive
vendors, to research your question. It has been the case with many
offerings in the past: I don't have notes about exact model numbers.

If you want to go find such pairings, they are often indicated by one of
the pair having drive model suffix "A" or "AT" (for ATA), and the other "S"
(for SCSI).

Rick Moen wrote:
> serge <serge_mtu DeleteThis @mtu-net.ru> wrote:
>
>
>>*Often, the same drive mechanism will be sold as both ATA and SCSI
>>depending only on the interface board snapped onto each individual
>>unit.*
>>
>>which one?
>
>
> <sigh>
>
> I'd have to spend time researching the current offerings from hard drive
> vendors, to research your question. It has been the case with many
> offerings in the past: I don't have notes about exact model numbers.
>
> If you want to go find such pairings, they are often indicated by one of
> the pair having drive model suffix "A" or "AT" (for ATA), and the other "S"
> (for SCSI).

While it *used* to be true that some drives were sold as both SCSI and
ATA, that doesn't seem to be the case any more. ATA and SATA disks spin
at 7200 RPM while SCSI disks spin at 10000 or 15000 RPM. (At least I
can't find any manufacturer still making 7200 RPM SCSI disks.) Clearly
they're not using the same mechanisms.

The Western Digital Raptors are the only SATA disks that spin at 10000
RPM (AFAIK, that's still true). But WD doesn't sell SCSI drives at all,
so it would seem highly unlikely that their 10000 RPM SATA disks share
anything with 10000 RPM SCSI disks.

John-Paul Stewart <jpstewart.TakeThisOut@binaryfoundry.ca> wrote:

> While it *used* to be true that some drives were sold as both SCSI and
> ATA, that doesn't seem to be the case any more. ATA and SATA disks spin
> at 7200 RPM while SCSI disks spin at 10000 or 15000 RPM. (At least I
> can't find any manufacturer still making 7200 RPM SCSI disks.) Clearly
> they're not using the same mechanisms.

At a glance...

Seagate Nearline NL35-series come with both SATA and Serial-Attached
SCSI-compatible Fiber Channel interfaces. (Admittedly, that's a bit
exotic. ;-> )

Maxtor have indeed divided their enterprise line into MaXLine 5400/7200
RPM ATA and Atlas 10K/15K SCSI / SAS.

WDC have indeed gone 100% SATA/PATA.

Hitachi (ne IBM) Ultrastar has gone 100% U320 and FC.
Deskstar/Travelstar/Endurastar is now all SATA/PATA.

Fujitsu follows the distinction you mention of SCSI starting at 10kRPM.

Samsung appears to be making only PATA/PATA any more, topping out at
7200RPM.


Basically, you're absolutely right. It _used_ to be the case that drive
chassises were sometimes built with either interface, but continuing
market segmentation seems to have put an end to that.

In article <dh6r9c$aeq$1@gavrilo.mtu.ru>,
"serge" <serge_mtu.RemoveThis@mtu-net.ru> wrote:

> I wonder if sata disks realy perform well?
> I'd like to have a look upon Hdparm -t,
> The disk model and the card
>
> Does the latest 2.6 kernel have full support for sata?
>
> Thank you


This is in a Windows context but in Anandtech's review of dual core
processors he pointed out that NCQ which some versions of SATA support
has a strong impact on intense multitasking tests:

See:
http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2389&p=8

for Seagate's take on NCQ:
http://www.seagate.com/products/interface/sata/benchmark.html

I am a Linux newbie so have nothing to offer in this context.

Roland

Joe Doe <None.DeleteThis@mail.utexas.edu> wrote:

> This is in a Windows context but in Anandtech's review of dual core
> processors he pointed out that NCQ which some versions of SATA support
> has a strong impact on intense multitasking tests:

Indeed it would.

> I am a Linux newbie so have nothing to offer in this context.

I can fill in: If you run one of the drivers from Jeff Garzik's libata
collection, it turns out that you might have preliminary NCQ support,
depending. See his pages for per-chipset details:

http://linux.yyz.us/sata/software-status.html#tcq