RAID - SATA & SATA II confusion

[mikem891]

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

 

[Paul]

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_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/products/products.asp?driveid=503

Benchmarks
http://www.xbitlabs.com/articles/storage/display/1tb-14hdd-roundup_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/library/cc773268.aspx

"Using GPT Drives" (GUID partition table versus MBR type)
http://www.microsoft.com/whdc/device/storage/GPT-on-x64.mspx

Paul

 

[mikem891]

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_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/products/products.asp?driveid=503

Benchmarkshttp://www.xbitlabs.com/articles/storage/display/1tb-14hdd-roundup_20...

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/library/cc773268.aspx

"Using GPT Drives" (GUID partition table versus MBR type)http://www.microsoft.com/whdc/device/storage/GPT-on-x64.mspx

    Paul- Hide quoted text -

- Show quoted text -

Thanks a lot, it was really useful and instructive. I will definively
take a closer look at the RE3 drives, I thought that the entreprise
drives were more expensive, and I saw some comments about problems
with adaptec RAID controllers and non-entreprise grade drives like you
said, but I didn't see any comments about the caviar black serie.

I still don't understand why adaptec use the term Serial ATA II for
some of there controllers if we shouldn't use it. Or maybe Serial ATA
II and SATA II doesn't mean the same thing, but I saw on many sites
that it does... and shouldn't be used. for example:
http://www.adaptec.com/en-US/products/Controllers/Hardware/sata/value/AAR-2820SA/

I also didn't see any problems with my ASUS P6T Deluxe V2 motherboard
& the 2405, but if someone knows a known problem please let me know.

Thanks again

 

[Paul]

Thanks a lot, it was really useful and instructive. I will definively
take a closer look at the RE3 drives, I thought that the entreprise
drives were more expensive, and I saw some comments about problems
with adaptec RAID controllers and non-entreprise grade drives like you
said, but I didn't see any comments about the caviar black serie.

I still don't understand why adaptec use the term Serial ATA II for
some of there controllers if we shouldn't use it. Or maybe Serial ATA
II and SATA II doesn't mean the same thing, but I saw on many sites
that it does... and shouldn't be used. for example:
http://www.adaptec.com/en-US/products/Controllers/Hardware/sata/value/AAR-2820SA/

I also didn't see any problems with my ASUS P6T Deluxe V2 motherboard
& the 2405, but if someone knows a known problem please let me know.

Thanks again

I expect the Adaptec marketing staff have a lot of trouble balancing
the suggestions on that FAQ page, with the ability to convince
customers they're getting the right product. And marketing dribble
is not the place for them to be putting in long winded explanations
about terminology. The result will be some adverts with non-compliant
terminology, and other adverts which are downright confusing.

Paul

 

[mikem891]

I expect the Adaptec marketing staff have a lot of trouble balancing
the suggestions on that FAQ page, with the ability to convince
customers they're getting the right product. And marketing dribble
is not the place for them to be putting in long winded explanations
about terminology. The result will be some adverts with non-compliant
terminology, and other adverts which are downright confusing.

    Paul- Hide quoted text -

- Show quoted text -

I just have a last question concerning the drives firmware versions.
The last time I built a RAID 0 array I was lucky and received 2 HD
with the same firmware. I once saw that for maximum performance and to
prevent problems we should always use drives of the same firmware
version when building a RAID array. Is it true? It makes sense to me.
But this time, since I will use 4 drives I have not many chances to
receive all HD with the same firmware. Can it really cause me some
problems, I guess I could flash the firmware on some of them, but I
also saw that HD companies (like seagate, I don't know for WD) don't
let anybody access to the firmware updates, so I'm afraid this
solution could not be possible. Anyone had experienced this situation?
I wonder if I could ask the online store (tigerdirect, cnix,etc..) if
they can send me exactly the same HDs, but I doupt so...

Thanks again