SATA link up 1.5 Gbps

> If you need so many disk drives
~
we were talking theoretically here based on the Math of throughput on each
devide
~
> If you need SATA controller with more than two SATA connectors, you have a
plenty of them. Adaptec, AOC (3ware), LSI and some others are producing
those controllers (usually SAS/SATA), and they are working perfectly.
~
I was actually asking for SATA controller cards based on the PCI-Express
interface
~
I saw quite a few at newegg.com under:
~
> Computer Hardware > Hard Drives > Controllers / RAID Cards
~
However they were all either RAID cards or were designed for SAS external
ports
~
In the same way they have plain 4 port PCI Ultra ATA 133 IDE controller
cards, I wonder why is it they don't have 8 port PCI-Express to SATA II
ones
~
regards
lbrtchx

Previously Albretch Mueller <lbrtchx@gmail.com> wrote:
[...]
> I was actually asking for SATA controller cards based on the PCI-Express
> interface
> ~
> I saw quite a few at newegg.com under:
> ~
> > Computer Hardware > Hard Drives > Controllers / RAID Cards
> ~
> However they were all either RAID cards or were designed for SAS external
> ports
> ~
> In the same way they have plain 4 port PCI Ultra ATA 133 IDE controller
> cards, I wonder why is it they don't have 8 port PCI-Express to SATA II
> ones

My guess would be that not enough people understand software RAID at
the moment and hence the market is currently too small to create
the PCI-E versions fast. In addition, many mainboards have a lot
of SATA connectors today, that you can use for software RAID.
Getting a board with 8 SATA interfaces that are fast enough to
build 8 disk RAID arrays in software should be unproblematic.

As to RAID controllers: It is expensive, but if you really want, you
can typically configure all disks as "pass trough", "raw" or
"unraided" and use them as ordinary controllers. You still need the
correct drivers.

As for SAS controllers, they can deal with SATA disks as well, but
need an adapter (different connector).

Arno

Hi!

Arno Wagner wrote:
> Previously Igor Batinic <_ime_._prezime_@email.htnet.hr> wrote:
>
>> Why? 2.0 16x?
>
>> If you need so many disk drives, first of all, you'll never mount them
>> in only one desktop (or even server) case. On the other hand, so many
>> disk drives will be in RAID arrays, not standalone. Also, it is almost
>> impossible to imagine system who needs to write simultaneously on 20
>> different drives. In those cases SAN, NAS or DAS systems will be much
>> preffered solution.
>
> Sorry, I have had an * disk and a 4 disk RAID array (software RAID)
> in one server. Thet is not the reason PCI-E 16x is inappropriate.
> The reason is that it has far, far too much bandwidth for 8 disks.

Actually, I really don't see the reason why to use PCIe 16x. Most server
systems and also HBA adapters are not using PCIe 16x simply because -
it's not needed. )

>> If you need SATA controller with more than two SATA connectors, you have
>> a plenty of them. Adaptec, AOC (3ware), LSI and some others are
>> producing those controllers (usually SAS/SATA), and they are working
>> perfectly.
>
> True. Just look a bit. Make sure your disks do not saturate
> the bus. For example, getting a PCI 4 port SATA controller
> would be a bad idea for hardware RAID, as 4 modern disks
> can saturate even an 270MB/s 66MHz PIC slot.

That's normal. The only problem is using PCI bus for such a purpose.

Best regards,

Iggy

Arno Wagner wrote in news:6bunoiF3dme79U1@mid.individual.net
> Previously Albretch Mueller <lbrtchx@gmail.com> wrote:
> > Arno Wagner wrote:
> > > I think it does, but it matters very little. You will not get any
> > > perceptable speed-up over 1.5GB. The one advantage at this time
> > > is better compatibility, and with WDs shoddy SATA protocol
> > > implementation, this may be an issue.
> > >
> > > Arno
> > ~
> > Hmm! Arno, you say "it matters very little. You will not get any
> > perceptable speed-up over 1.5GB" without saying why ;-)

> Why would you get a speed-up? This is the interface speed, not the
> drive speed.

> Drive speed is much lower.

Only slightly, Babblebot.

>
> > ~
> > Which combination of (Motherboard + I/O subsystem + BIOS + (?)) will let
> > you have your cake and eat it too?
>
> None.
>
> > ~
> > Also, which manufacturers have more useful SATA, S.M.A.R.T, TLRE, . . .
> > implementations so that you may better predict when drives are about to
> > fail and possibly the physical reasons why
>
> You need to interpret yourself for that. Basically they are all
> usable. Seagate makes pretty bad drives at the moment. WD has
> compatibility issues in the Interface. Maxtor still sucks.
> Get Samsung or Hitachi.
>
> > ~ I am thinking of implementing RAID 5 using a Linux (or BSD)
> > software-based RAID any good best practices out there?
>
> Get a controller that is PCI-E attacjed, to acvoid the bus
> bottleneck. Can be a board/chipset -integrated one. Make sure
> to moditor the array (mdadm) and the SMART status of the disks
> (smartd, look for pending secors and reallocated sectors in
> particulsr) and make sure error notificatin by both tools work.
>
> Arno