Intel SASWT4I SAS/SATA Controller Question

[joehopf]

Hey there!

I want to assemble a cheap storage sytem based on the Norco RPC-4020 Case.

When searching for controllers I found this one:

Intel® RAID Controller SASWT4I
http://www.intel.com/Assets/PDF/prodbrief/RAID_SASWT4I_prodbrief.pdf

This is a quote form the Spec Sheet:

Scalability. Supports up to 122 physical devices in SAS mode which is ideal 
for employing JBODs (Just a Bunch Of Disks) or up to 14 devices in RAID 
0, 1, 1E/10E mode through direct connect device attachment or through 
expander backplane support.

Does that mean I can attatch 14 SATA drives directly to the controller using SFF-8087 - 4x SATA breakout cables?

That would be nice because then I can choose a mainboard that has 6 Onboard SATA and i can connect all 20 bays while only spending 155$ on the controller and like another 100$ on cables.

Would that work? And why is it 14 and not 16 when there are 4 Ports?

I am really confused about all the breakout/fanout/(edge-)expanding/multiplying/channel stuff...

 

[Nelius]

It clearly states in the spec sheet, that you only get 4 x SATA ports on that card. If you want to connect more than that, you need to use a SAS expander.

 

[joehopf]

Sorry but I still dont get it.

I read in the spec "SAS or SATA Storage".

Which means there should be SAS "plugs"? Because I can plug a SATA drive into a SAS plug but not the other way round?

And what is the differences between the 122 and the 14 drives they sate? If only 4 are supported without expanding hardware whats the difference between those two numbers?

And on another Vendors site they state:

Connectivity
Host interface PCIe
Ports quantity 14
Interface SAS & SATA
Connector(s) 4xSATA & 1 SAS

Well and afaik on one PORT there can be one drive or with multipliers up to 15 SATA drives or with expanders up to >65k sas devices.

 

[treadstone]

The Intel SASWT4I is a rebranded LSI SAS3041E adapter.

http://www.lsi.com/storage_home/products_home/host_bus_adapters/sas_hbas/lsisas3041er/

Features
- 3Gb/s per port
- (4) internal SATA x1 connectors
- Integrated RAID 0, 1, and 1E
- 4-lane 2.5Gb/s PCI Express
- MD-2 small form-factor design
- Connects to both SAS and SATA HDDs and tape drives
- Allows more than 122 total end-point devices
- Fusion-MPT architecture providing more than 140,000 I/Os per second
- Supports all major operating systems

This controller has 4 SATA ports and hence will only directly support 4 drives via SATA cables. If you intend on using more than 4 drives, you would have to use a reverse SATA to SFF-8087 breakout cable to connect to a SAS expander which in turn can connect to more drives.

I think you would be better off looking at a different controller. There are other alternatives in the same price range that give you at least 8 SAS/SATA ports via 2 SFF-8087 connectors.

 

[joehopf]

okay. now i get it. thanks!
still don't know where they take the number 14 from but your explanation clearifies my confusion!