BPN-SAS2-846EL1

[pgh5278]

This guy has several of these for sale, some sold, selling BPN or BPN with power distributor / cables etc

Supermicro Backplane Expander BPN-SAS2-846EL1 with 6Gb/s SAS2 for 24 Hard Drives

 

[PGlover]

How would you connect 24 drives? What breakout cables would I need?

 

[james23]

defiantly a decent price on the 24bay sas2 expander, as the sas1 846el1 s are going for ~120$.
A note to anyone looking though: the auction this seller has with the expander + PDB (power distributor, the thing the actual power supplies slide INTO), the PDB is a 2U type (as its for the 36 bay, 1400w 4U chassis, not the more common 4U 24 bay 846 chassis.) on the 36 bay its a 2u PDB as the MB is raised up 2U to make room for the additional 12 x HDD bays in the rear.

So if you are thinking of taking a fully bare 24 bay 4U 846 and putting this PDB in it, it will *not* fit / not work.

 

[james23]

How would you connect 24 drives? What breakout cables would I need?

its an expander board, so if your HBA / Raid-Card supports this LSI expander chip (most do) then you only need to run a single SFF-8087 from HBA to the expander to access all 24x bays. (the normal cable, you often see SFF-8087 to 4x sata fan outs, here you need a "sff8087 to sff8087")

 

[PGlover]

its an expander board, so if your HBA / Raid-Card supports this LSI expander chip (most do) then you only need to run a single SFF-8087 from HBA to the expander to access all 24x bays. (the normal cable, you often see SFF-8087 to 4x sata fan outs, here you need a "sff8087 to sff8087")

So how many HBA/RAID cards would I need to connect all 24 ports?

 

[pgh5278]

So how many HBA/RAID cards would I need to connect all 24 ports?

one

 

[james23]

So how many HBA/RAID cards would I need to connect all 24 ports?

You ever notice how LSI or Adaptec will sell a 4 port a 8 port and a 16 port raid card but when you read the specs for each they all say they support up to 255 drives. This is what that 255 is referring to (this being an expander or and expander backplane to enable up to 255 drives).

So a 4 port raid card connected to this will have 24 drives to use. There is a bandwidth trade off though as you are only using 1 X 8087 cable / 1 X 8087 port on the raid card your max theoretical is 4 X SATA 1,2,3. (It's sata2 in this case). Whereas if you had a 16 or 24 PORT raid card , your drives would each have full SATA speed (not limited to 4x max)... However in my experience this 4x SATA bandwidth limit doesn't really come into play on raid cards as the cards processor can rarely saturate 4x anyway.

Another example : I have a Adaptec 8405 (4 port raid card but SATA3 or sas3 or SATA 12.0 ) going to a 36 port Intel sata3 expander. So the 4 port raid card can see up to 36 drives but it's max theoretical bandwidth to access those 36 drives is 4x 1200 Mb/s (4 X sata3) so about 4800 Mb/s.

Realistically I see 2-3000 Mb/s max.

 

[Havs]

So how many HBA/RAID cards would I need to connect all 24 ports?

one

To expand on that, you only need one SFF-8087 connector. So, as an example, you'd only need an LSI-9260-4i vs an 8i, since the 8i has two 8087's. It might save you a small bit of money purchasing a card if you know you're going down the Supermicro 24 bay server route. Bandwidth shouldn't be an issue; the SFF-8087 has four lanes. Interfacing with this backplane, each lane will carry up to 6 Gb/s. That'll give each drive in a 24 drive enclosure ~125 MB/s if all 24 drives were working at 100%, which they likely won't be.

 

[rnavarro]

defiantly a decent price on the 24bay sas2 expander, as the sas1 846el1 s are going for ~120$.
A note to anyone looking though: the auction this seller has with the expander + PDB (power distributor, the thing the actual power supplies slide INTO), the PDB is a 2U type (as its for the 36 bay, 1400w 4U chassis, not the more common 4U 24 bay 846 chassis.) on the 36 bay its a 2u PDB as the MB is raised up 2U to make room for the additional 12 x HDD bays in the rear.

So if you are thinking of taking a fully bare 24 bay 4U 846 and putting this PDB in it, it will *not* fit / not work.

--Edit--

Looks like you were talking about a bare chassis with no mobo or standard PSU connections.

My chassis is populated with the standard molex connectors should I should be able to use this if I'm understanding things properly.


Wow thanks much james23!

I was right about to pull the trigger, but I have an 846....*phew*

 

[james23]

I know this all can be a bit confusing until you actually work with the parts in your hand so let me try to clear up a bit:

If you currently have a 846 , 4u , 24bay CHASSIS WITH a PDB and you have 1 or 2 power supplies - then all you need is a back-plane (ie: BPN-SAS1-846EL1 is a back-plane and expander).

Attached is a picture ive marked of a PDB (BLUE circle) and a PowerSupply (green circle , click thumb to enlarge).

The power supply slides INTO the chasis and connects/plugs into the PDB (an 846 4u chassis can accept one or two power supplies, but only has ONE PDB)

PDB= Power Distribution Board




Let me know if you have any ?

 

[Fritz]

I bought a package from wholesale_treasures. They shipped it "Direct Signature Required" which caused me major grief. I managed to be here for the 3rd and final delivery attempt but it cost me. I emailed them and let them know how I felt. They apologized and refunded me 15%. I'd say they handled it pretty well. Had I known it was coming sig required I could have planned for it.

 

[frogtech]

I've also been caused some grief before by direct signature. USPS is one of the worst offenders for requiring a signature since they come so early for me. Getting to the po to pick up is nearly impossible.

 

[TechTrend]

you only need to run a single SFF-8087 from HBA to the expander to access all 24x bays

'lsiutil' indeed shows only 4 channels when connecting an LSI 2008 (PERC H310) to a BPN-SAS2-846EL1. Yet many pre-configured systems on eBay come with two SFF-8087 cables connected to the backplane. Is there a use for the second port, e.g. can it be enabled to get 8 channels and a higher total throughput?

 

[frogtech]

Did you really have to necro this thread to ask that? The technical white page for this backplane on google will tell you everything you need to know.

 

[TechTrend]

Did you really have to necro this thread to ask that? The technical white page for this backplane on google will tell you everything you need to know.

I did review the BPN-SAS2-846EL1 documentation before posting. My post attempts to find a reason why many pre-configured systems with a single backplane use a second SFF-8087 cable when only one appears to be required. The backplane documentation does not answer that question and has no technical info on the LSI component options or registers. LSIUTIL allows configuration of many LSI component options. If some systems use the J2 connector on single backplane systems, a possible explanation is that the LSI SAS2 expander has options beyond the preconfigured alternatives listed on the backplane documentation. Of course, another possible explanation is that the cable was populated by error. But neither your response nor the documentation are of any help in determining this.

As to whether my post should be on a new thread or not, that is a matter of preference. Reading multiple discussions on the same topic in a single thread is convenient. IMO backplane options and cabling does not tend to be granular enough to justify a large number of topics. Other members can certainly disagree, but there are precedents implying that is not an absolute rule. There are threads here running over 6 months with close to 2,000 posts that some members evidently find useful.

 

[Fritz]

I bought 4 SM 846 bare chassis last year and all 4 of them came with 2 cables. I too was wondering about this and after consulting the manual I just pulled the extras out and threw them in a drawer. I have no idea why they all came with 2.

 

[Arthur Krewat]

That second cable is either to pass back to the RAID controller and provide two paths to each SAS drive (if the RAID controller can handle it) or a passthrough to an external SAS connector for daisy-chaining.

I've been researching these Supermicro 846's for a while now, trying to decide if I want to bother to replace my dual-MD1000/R710 Dell setup.