SATA drives via external SAS cable question

[imanz]

Hello everyone, any insight on this would be highly appreciated...

My current system components when all is working:
8 x 3TB WE Red
Intel Atom C2750 on a Supermicro motherboard (A1SAi-2750F)
32GB memory
IBM M1015 SAS controller

So my goal was to add an additional 4 drives to this system but I had recently (4 months ago) moved this system into a new case which I quite like so I thought I would get a SAS enclosure and convert one of the internal SFF-8087 connections on my M1015 to an external one. I ended up purchasing the following components:
Silverstone TS431S mini sas enclosure - http://www.silverstonetek.com/product.php?pid=423&area=en
An SFF-8087 to SFF-8088 bracket adapter (very much like this http://www.amazon.com/dp/B00EMTCEI6/?tag=ozlp-20 )
A 1m SFF-8087 to SFF-8087 cable to connect that bracket to the IBM 1015 internal port
And lastly a SFF-8088 to SFF-8088 to connect the back of the NAS to the back of that enclosure... The issue is that regardless of how I have attempted to configure this setup both FreeNAS and the SAS controller configuration utility (during the boot process) do not see any of the drives I have tried putting in the enclosure.

Now I haven't bought the drives that I will use in the enclosure but I had two western digital RED drives laying around (SATA drives) and those are the ones I used in the enclosure.

My concern here is that it seems that SATA has a cable length of 1M while SAS is much higher. I was under the impression however that the connection is counted as point to point, so the distance from the IBM M1015 controller in the server all the way to the termination of the SFF-8088 on the SAS enclosure would be considered SAS and only the actual drive connection is SATA? Or is the entire link dropped to SATA due to the drives? Could this be causing my issue as I am using a total of 3M of cabling which is obviously over the maximum for SATA.

If my issue is the cable length does anyone have any ideas on how to make this work without having to buy SAS drives? Biggest issue I have come across is finding .5M SAS cables.. Any suggestion is appreciated!

 

[Ericloewe]

My concern here is that it seems that SATA has a cable length of 1M while SAS is much higher. I was under the impression however that the connection is counted as point to point, so the distance from the IBM M1015 controller in the server all the way to the termination of the SFF-8088 on the SAS enclosure would be considered SAS and only the actual drive connection is SATA?

So, the electrical part just magically turns into SATA once it passes through a gender changer?

Or is the entire link dropped to SATA due to the drives?

It's SATA signalling from the drive to the first SAS device.

Could this be causing my issue as I am using a total of 3M of cabling which is obviously over the maximum for SATA.

Definitely.

If my issue is the cable length does anyone have any ideas on how to make this work without having to buy SAS drives?

Add an expander in the external chassis. The link to the expander will be SAS, and thus operate over longer distances. The expander will then speak SATA with the drives.

 

[jgreco]

So, the electrical part just magically turns into SATA once it passes through a gender changer?

Now now @Ericloewe be nice.

But exactly what Ericloewe says, you're trying to run SATA over 3M. Won't work.

Kinda surprised it doesn't even see the drives, I'd kinda expect it to "work" but not actually WORK.

Your other option might be to see if you can find SAS drives that are in the price range. A SAS expander is usually a bit pricey and for only four drives it might be cheaper to fix the drives than fix the SAS/SATA.

 

[imanz]

So, the electrical part just magically turns into SATA once it passes through a gender changer?


It's SATA signalling from the drive to the first SAS device.


Definitely.


Add an expander in the external chassis. The link to the expander will be SAS, and thus operate over longer distances. The expander will then speak SATA with the drives.

Just as an update, I removed all the components and set it all up without fully installing all the parts inside the case. Rebooted the NAS and everything works perfectly.. I inspected the PCIE bracket that converts from 8087 to 8088 inside the NAS and it seems like it was soldered by a blind person. Will definetly be getting that replaced atleast. At this point I am not exactly sure what is going on. Also, I was hoping I did not need a SAS expander for just 4 drives as the silverstone case is specifically advertised to work with SAS/SATA drives and is not sold as just a 'case'. For the cost of the enclosure I can simply build my own with a SAS expander..

 

[Ericloewe]

Just as an update, I removed all the components and set it all up without fully installing all the parts inside the case. Rebooted the NAS and everything works perfectly.. I inspected the PCIE bracket that converts from 8087 to 8088 inside the NAS and it seems like it was soldered by a blind person. Will definetly be getting that replaced atleast. At this point I am not exactly sure what is going on. Also, I was hoping I did not need a SAS expander for just 4 drives as the silverstone case is specifically advertised to work with SAS/SATA drives and is not sold as just a 'case'. For the cost of the enclosure I can simply build my own with a SAS expander..

Well, that certainly doesn't help. Keep in mind, though, that flakiness is expected if you do run SATA signalling for over 1m, particularly outside of the shielded confines of the system's chassis.

That chassis should work reasonably enough with SAS drives, but it's almost unusable (within spec) with SATA drives.

 

[AVB]

I think the least expensive solution would be to buy a different HBA that has 1 internal and 1 external connection and sell the HBA you have to recoup some of the price. That way you'd only have 1 cable to worry about and should be able to keep it at 1M or less. Just a thought.

 

[Ericloewe]

I think the least expensive solution would be to buy a different HBA that has 1 internal and 1 external connection and sell the HBA you have to recoup some of the price. That way you'd only have 1 cable to worry about and should be able to keep it at 1M or less. Just a thought.

It's still a bit tricky, to be honest. 1m is awfully restrictive.

 

[AVB]

I've not had any problem with 1M esata wires and I had 3 of them going at one point. Down to 1 now but stiil its been in use for at least 4 years. I guess it comes down to how far away he needs to have that 4 drive case.

 

[jgreco]

I've not had any problem with 1M esata wires and I had 3 of them going at one point. Down to 1 now but stiil its been in use for at least 4 years. I guess it comes down to how far away he needs to have that 4 drive case.

Well, sure, there's a little extra margin in the "1M" number. But that's not "2M" or "3M" or even "1.5M".