Dell 6TDVN SAS Expander

Discussion in 'RAID Controllers and Host Bus Adapters' started by Dave Corder, Dec 23, 2018.

  1. Dave Corder

    Dave Corder Member

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    HI all,

    I stumbled across a seller on eBay selling Dell 6TDVN SAS expanders for around $20. These are pulls from something (though I haven't been able to figure out what yet). They have three SFF-8088 external SAS ports and six SFF-8087 internal SAS ports.

    I took a gamble and bought one, hoping maybe I could use it in place of some HP SAS expanders which don't support SATA3 speeds. When I got it, I pulled off the heatsink to find an LSI SAS2X36 expander chip. So far so good. It turns out that the power connector is a standard P4 12v CPU connector. I plugged it into a Dell H310 (flashed to LSI IT firmware 20.00.07.00) in a spare PC with a SFF-8087 to SFF-8087 cable and booted an Ubuntu Live CD. I was able to see the expander on the SCSI bus with 'lsscsi' and able to poke around its setup a little bit with a copy of xflash I found online (I recall the firmware was reported as version "00.50.00.00".

    Happy with the test results so far, I went ahead and ordered 2 more. Then things started to get strange. The next day, I repeated the same connection test with the same cards and cables and I got nothing. No links detected, no sign of the card in the SAS topology at all. Since then I've tried all the expanders, a couple different cables, and a different HBA (a Dell H200, also with IT firmware flashed to it) and I keep getting the same results.

    I have a SFF-8087 to SFF-8088 cable arriving tomorrow, just in case for some reason the expander cards became picky about what ports are used for uplinks and downlinks (even though the SAS2X36 isn't supposed to care).

    Does anyone else have any experience with these SAS expanders or any suggestions on what I can try to make sure they work (short of replacing the HP expanders in my DASes and praying that they work properly)?
     
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  2. Philmatic

    Philmatic Member

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    I’m hoping there are others who have experience. I too found a killer deal on this SAS expander on eBay ($22 shipped) so I just ordered it. I also bought a HP SAS Expander just in case for my second and third DAS build.

    Worse case is that I’m out $22, but I really really dig the three external connections, I could use this as the main SAS switch across both of my DAS’ connecting to my fully loaded RPC-4224 and still have a spare connector for a third DAS.
     
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  3. Philmatic

    Philmatic Member

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    Anyone able to mount this in a standard ATX case without resorting to any MacGuyvering?
     
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  4. BLinux

    BLinux Well-Known Member

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    @Dave Corder @Philmatic I don't know that much about this SAS expander, but I would be very cautious about plugging that power cable into the board. 12V doesn't "feel" like the correct voltage to drive something like the LSI SAS2X36 chip, I would have expected 3.3V or 5V. Dell some times does some really weird things with their power cables just to mess with people; I know some of their older motherboards had a standard ATX power connector, but they would deliberately swap 2 or 4 pins, and if you plugged in a standard ATX power connection from a regular PSU, it would fry the board. So, just because it fits, doesn't mean it will work.

    I would search to see if you can find more detail specifications on what voltage should be on those 4-pins.

    Again, I know nothing about this particular expander, so maybe everything i'm saying doesn't matter. But I would just be cautious.
     
    #4
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  5. Philmatic

    Philmatic Member

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    @Dave Corder I'm having the same issue as you, it powers up just fine and the LED turns on, but no matter what combination of external or internal ports I use. I cannot see any disks past the expander, I can't see the expander itself either (I understand it's a passive device with no drivers, but it should still be detected in MegaRAID Storage Manager).

    Seems like a bust, oh well. It would have been a fantastic device to build JBOD units with, the 3 external ports would allow for daisy-chaining or dual-linking.
     
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  6. Dave Corder

    Dave Corder Member

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    @Philmatic I've been in touch with someone on the FreeNAS forums who uses one of these successfully and, basically, he says it just works for him most of the time, but sometimes on reboot he has to unplug and power drain everything and reconnect before things will be recognized (when connected to his M1015 card).

    I just got back from vacation and it may be a while before I have some more time to tinker with the expander, but I'll provide more updates as I have them.
     
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  7. Philmatic

    Philmatic Member

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    Interesting. I’ll try mine again tonight.
     
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  8. Philmatic

    Philmatic Member

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    No dice. Tried several P4 connectors, each one lights up the Expander, but no matter what port I connect it to, extrernal or internal and no matter which numbered port I try, I cannot get either my HP SAS Expander's external port to see it (And anything attached to it) or my 9201-16e's external ports to see it.

    Shame, it would have been a dream to put in my Norco DS-24D with 6 SFF-8088 ports, I would have gotten 2 -3 and made myself a little switch out of the unit.
     
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  9. ari2asem

    ari2asem Member

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    guys, maybe is this expander dead because of 12volt 4pin atx connector?

    i have rackable se3016 16 bay unit with 4pin atx, this 4pin has power connection suiteable for molex 4pin, e.g. 5v and 12v power lines.

    have you tried with this 5v and 12v lines on a new dell expander?
     
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  10. Tiberizzle

    Tiberizzle New Member

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    I stumbled across these recently on eBay and shortly afterwards located this thread while researching them.

    I believe these are the SAS expander internal to the EMM of the MD1280.

    [​IMG]

    It is the only Dell storage chassis I have been able to locate with a similar spacing of the external SAS connections.

    This chipset LSI SAS2X36 is a SAS switch which supports multipath connection to chained SAS expander, disk, or controllers with no restriction as to what connects to which port unless using custom firmware.

    The chassis is arranged as 6 x 14 disk carriers in 2 shelves, and the EMM are specified to be redundant, with 3 external ports that would leave 24 ports internal per expander, or 12 ports to each shelf. I would then guess those are arranged as 4 ports to each drive carrier of that shelf, which would have an internal expander and allow the fully redundant operation specified for the EMMs. The drive carrier internal expander, assuming they are also LSI SAS2x36 and support dual port SAS, would require 2x14 ports which would leave exactly 2x4 ports for redundant connection to the EMMs. I haven't been able to locate a picture of the innards of an EMM, drive carrier or the chassis to confirm the theory.

    Of note, the specifications for this chassis explicitly state:

    On the underside picture of the item it is clear that not all pins of the 4-pin power connector are connected to the power/ground planes:

    [​IMG]

    The routing of pin 4 appears consistent with it supplying an auxiliary voltage, probably the 5V standby power referred to in the documentation.

    I also have the Chenbro LSI SAS2x36-based expander and it does consume Molex 12V+5V. Interestingly, the Intel implementations of this chip appear to consume 3.3V and 12V at the board level.

    There are references on the silk screen of the Dell part to test points for 1.0V, 1.8V, and 3.3V, so I assume the standby power is either not applied to the SAS chipset, 5V is close enough, or is converted first.

    I've purchased 4 of them and will let you know how it goes.
     
    #10
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  11. Dave Corder

    Dave Corder Member

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    The 12V/5V sounds slightly promising. Thanks for the research, Tiberizzle. I've been wondering where these modules actually came from. Please keep us posted!
     
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  12. Tiberizzle

    Tiberizzle New Member

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    Unfortunately yours is probably toast if that theory is true. At least the replacement will be cheap, eh? ;)
     
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  13. Philmatic

    Philmatic Member

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    Ooooh, thanks for the update! Let us know, mine still lights up so I don’t think it’s dead.
     
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  14. Tiberizzle

    Tiberizzle New Member

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    So I did a little more visual analysis of the board layout to try to find an identifiable interface or chip that I could reference to a voltage specification to confirm the pinout.

    I noticed pin 4 of the power connector goes directly to what should be pin 2 VCC on the black connector labeled serial debug (it should specifically be GND/VCC/TX/RX in that order) and 3.3 or 5V are common for that type of interface. Pin 1 and pin 2 are most likely at the same voltage level as they both have vias next to them from the bottom layer whereas pin 3 does not. Pin 3 can't be ground as +12V on 5V and +12V on GND would result in no net voltage and no lights and probably a short to ground via any other connections. Pin 3 appears to have blind vias under the connector from some angles and surface layer and/or upper inner layer routing would be consistent with +12V supply for the MOSFET H-bridge directly below the power connector.

    So, I am concluding the full pinout is most likely GND/GND/12V/5V in that order.

    The grounds should be trivial to confirm non-destructively by testing for continuity between the two pins and e.g. the solder mask of the screw holes if anyone who already has theirs and a multimeter wants to check, confirming both pins have continuity to ground would pretty much guarantee this pinout is correct.

    Also I found this:

    [​IMG]

    I wonder what you could possibly connect to with a 6 inch SATA cable, perhaps the midplane connector breakout board internal to the EMM? :p
     
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    Last edited: Mar 25, 2019
  15. Tiberizzle

    Tiberizzle New Member

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    Jeez that was hard to find. Apparently the MD1280 was called the Compellent SC280 previously. It was also available from Sea Micro, Xyratex, and Open Storage Solutions as the SP-2584. Crazy.

    [​IMG]

    Being such a niche item I think it provides an unusually transparent view into the wild world of e-cycling. Several sellers trying to move the Dell chassis at anywhere from $4000 - $40,000, a handful seem to have their hands on the EMMs without knowing what it even is, and a few more are just ripping out the boards and either listing as new (lol) and holding out for hundreds of dollars or chucking them up as used for $20 a pop, heh.
     
    #15
    Last edited: Mar 25, 2019
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  16. Tiberizzle

    Tiberizzle New Member

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    I confirmed continuity between pins 1-2-GND and continuity between pin 3 and one of the power MOSFET terminals, and pin 4 must be 5V from earlier analysis, so the power connector is definitely GND/GND/12V/5V as stated earlier.

    I have not powered one on yet and probably won't bother until I order some chassis and have an idea for mounting and I/O shield but I'm sure that's the correct pinout at this poibnt
     
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  17. ari2asem

    ari2asem Member

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    so, that was also my suggestion. because i have a sgi rackable jbod unit. the sas-card of rackable has 4pin eps layout. but pin or power layout is same as molex, ground, 12v, 5v, ground.
    the ppl here who connected this dell expander to eps 12v, have fried their expander. because eps 12v has 2 times 12v

    take a look at this topic about sgi rackable unit, and my modifications.
    pay attention of P4 atx connector. i connected y-splitter of 4 pin molex to power up chenbro expander.


    Interesting cheap JBODs available
     
    #17
    Last edited: Mar 30, 2019
  18. Dave Corder

    Dave Corder Member

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    Thanks for doing the legwork, Tiberizzle. I have some pins and connectors on the way and hopefully I can find some time in the next couple of weeks to give it a try with one of my expanders. I also just ordered another one, just in case all three of the ones I have are fried.
     
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  19. mattp

    mattp New Member

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    I really appreciate the legwork as well, Tibrizzle. I went ahead and got one and re-pinned a molex splitter and did GND, GND, 12V, 5V and now have a working expander! I specifically sought this one out to replace my old HP expander in my franken-jbod as I have a ton of old SATA drives and the HP would get really wonky with them, but another SAS2X36 based expander handles it fine. With that, I see the Dell 6TDVN is listed as having 0500 firmware whereas my supermicro BPN-SAS2-EL1's chip is listed as 0717. Does anyone know if the firmware can be updated on these?
     
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  20. Philmatic

    Philmatic Member

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    Say whaaaaaaaaaaat? Now this thread is getting interesting!
     
    #20
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