mikem891@hotmail.com wrote:
> I want to add 4 WD caviar black 1TB 3 Gb/s SATA hard-drives in RAID 10
> in my system, but I do not want to use firmware/driver-based/fake/
> hostRAID so I won't use my motherboard's RAID capability (ASUS P6T
> deluxe V2 in RAID 5) and use hardware RAID instead. I'm planning to
> buy an adaptec RAID controller card.
>
> At first I wanted the Adaptec RAID 1420SA because it supports SATA II,
> but then I saw that it was using hostRAID so it's not a true hardware
> raid.
>
> Then I was looking at the Adaptec RAID 2405 card which is perfect for
> me, but It's not SATA II. I know that SATA II is a misnomer, but I
> found it really hard to know what exactly it means for adaptec. doest
> SATA II = SATA 3 Gb/s? Because on the 2405 specifications it doesn't
> support SATA II but there's 3 Gb/s transfer rate per ports. So does
> the 2405 will support my WD caviar black HDs at there full capacity or
> should I look for a SATA II card? I find it really confusing because
> no one seems to have the same definition for SATA II. And on adaptec's
> site I do not find any SATA II product that fits my needs (price &
> compatibilities) except the 2405.
>
> Any comments and advises will be greatly appreciated. even if it means
> buying another product than adaptec's cards.
>
> Thanks in advance
The two currently available SATA rates are 1.5Gb/sec and 3Gb/sec. The
advert here for the 2405 says 3Gb/sec, so it goes fast.
http://www.adaptec.com/en-US/support...raid/SAS-2405/
The reason I cannot use your terminology, is because of
FAQ pages like the following. This is the definition of when a
standards body is "epic fail". See how they're making
it easy to name and describe their technology ?
http://www.sata-io.org/6gbnamingguidelines.asp
So the only term that makes sense, is to refer
to the speed. 6Gb/sec interfaces aren't here yet,
so there is no point talking about them. 1.5Gb/sec
and 3Gb/sec interfaces are the current production
technologies.
To get the transfer rate in bytes/sec, divide by 10 - this
is due to the coding method, which sends 8 bits of data
via 10 bits on the cable (8b10b). So 3Gb/sec transfers
300MB/sec of data. The fastest SATA drive, is somewhere
in the 120MB/sec range (limited by head to platter interface),
so the main benefit from 300MB/sec, is "burst to cache"
on the controller board of each drive.
Before you buy your "black" drives, I recommend reading
the product description for the RE3. The RE3 spends less
time trying to read a defective sector, before responding
to the host (RAID controller). This can prevent the
RAID controller declaring the drive as not responding
and consequently making the array status degraded. I looked
in the Adaptec documentation, but I don't see a mechanism
to change how long the Adaptec waits, before declaring
a problem.
See TLER - I don't know how much difference this feature
actually makes. The performance level of Black and RE3
is different, so seek a benchmark before making your
purchase decision.
http://www.westerndigital.com/en/pro...sp?driveid=503
Benchmarks
http://www.xbitlabs.com/articles/sto..._20.html#sect0
Here is some more reading material, in case you decide to
go to four drive RAID0 at some point (4TB array size).
Your plan to build a 2TB RAID10 using four 1TB drives,
just comfortably fits with the convenience of "basic
disk" type. Going above 2TB, means changing a few
things. One of the Areca controllers I was reading
about, has a solution for that (fakes large sector
size). There is nothing to worry about, as far as
I know, with your current plan.
"Reviewing Storage Limits"
http://technet.microsoft.com/en-us/l.../cc773268.aspx
"Using GPT Drives" (GUID partition table versus MBR type)
http://www.microsoft.com/whdc/device...PT-on-x64.mspx
Paul