BUILD SAS 1 Backplane Question

[RemyZ]

I just ordered a Supermicro 825TQ 2U case off Ebay for a decent price. Was originally going to go for a 815TQ 1U case but decided against it since this case gives me flexibility and got a better price.
It comes with support for 8 Sata/SAS Drives by using the BPN-SAS-825TQ Backplane. This backplane is based off SAS1. I have read other people using this case fine but needed further clarification.

I understand that I won't ever saturate SATA III speeds with a regular 7200 RPM Drive but can saturate the speeds with a SSD Drive.

Since this backplane is based on Sata 1, Do I have to worry about saturating the backplane by using all 8x 7200 RPM Drives or with SSD Drives


If so what options do I have for swapping this backplane out for a more up to date one ?
( Looked on Website and no upgrade options for the specific case I bought )
The vendors link for specs doesnt say much
http://www.supermicro.com/manuals/other/BPN-SAS-825TQ.pdf

 

[Arwen]

It may be worse than speed. Reading around here, it appears that SAS 1 expanders are
limited to 2TB disks. SAS 2 fixed that. But don't quote me, I can't find the reference right
now.

 

[RemyZ]

Daaaamn Do you know of any SAS2/3 Backplanes that i can swap for ??

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[Ericloewe]

Since this backplane is based on Sata 1

Nope. SAS1 does 3Gb/s.

Theoretically, I would expect the backplanes to be compatible. I'd start by looking at chassis that have an SAS2 backplane. Figure out the models. Then see if they're compatible with your chassis.

It may be worse than speed. Reading around here, it appears that SAS 1 expanders are
limited to 2TB disks. SAS 2 fixed that.

I dunno, are the expanders limited as well? The HBAs definitely are, but that has to be some limitation in an internal LBA buffer or something. I don't see how an expander could be cost-downed in that way, since it only has to route commands and translate SATA and SAS. Of course, they might have artificially limited them.

 

[RemyZ]

Looking at BPN-SAS3-827TQ which may fit but idk

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[Ericloewe]

I would go with an SAS2 backplane.

In fact, unless you're going to add external drive chassis, I'd skip the expander backplanes and just get a plain, simple backplane with two SFF-8087 connectors. There's definitely a model available for your chassis and it should do SAS2 signalling. A standard 8-port HBA could directly drive all eight drives.

 

[Fuganater]

That backplane is a 'TQ' model which means it is not an expander. You have to use a breakout cable and each drive has it own SATA connection. Everything I read about it says it is SATA III.

 

[RemyZ]

Clueless. Help me understand so the TQ Model is not an expander and i can jus plug sata drives to the ports on the backplane and it will work or i need to get extra cabling??

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[Fuganater]

Clueless. Help me understand so the TQ Model is not an expander and i can jus plug sata drives to the ports on the backplane and it will work or i need to get extra cabling??

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So you could use the onboard SATA ports on your mobo or get a HBA (LSI 9211-8i) and use a SFF-8087 to SATA breakout cable. Then connect it to each port on the backplane. 8 bay = 8 ports.

To explain and expander in simplest terms, it is 1 cable for all drives. If it does not have an expander, like the TQ model does not, each drive requires a cable. There are other types out there but for you, this statement should clear up any confusion.

 

[RemyZ]

oh ok that clears it up. So for this motherboard
(Supermicro X11SSH-F) that has 8 onboard sata ports i can jus plug into backplane and then use individual cabling to each drive on the other side ? With this there should be no 2tb limitation or speed limitation?

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[Ericloewe]

oh ok that clears it up. So for this motherboard
(Supermicro X11SSH-F) that has 8 onboard sata ports i can jus plug into backplane and then use individual cabling to each drive on the other side ? With this there should be no 2tb limitation or speed limitation?

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Right, but SAS devices will not work.

 

[RemyZ]

Thanks for clearing that up for me. I freaked out after I ordered it and noticed the SAS1 backplane but all is well now.

 

[RemyZ]

Reading is fundamental lol
Here is a link that gave me a visual of the backplane since I don't have the case yet
https://www.thomas-krenn.com/en/wiki/BPN-SAS-825TQ_SAS/SATA_Backplane
Upon further reading it is SAS2/SATA6GB

 

[RemyZ]

I ended buying a 2x reverse breakout cables, hba lsu 8211 8i and 2x molex to 4x sata power connectors. Thnx for all the help

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[jgreco]

I dunno, are the expanders limited as well? The HBAs definitely are, but that has to be some limitation in an internal LBA buffer or something. I don't see how an expander could be cost-downed in that way, since it only has to route commands and translate SATA and SAS. Of course, they might have artificially limited them.

It's important to remember that the expander is a programmable device. I've heard reports that the more recent firmware for the 3Gbps expanders may allow >2.2TB drives, but it's pretty certain that older versions do not.