SAS2/SAT3 Expander for Supermicro 836 chassis available on eBay

Discussion in 'For Sale/ For Trade/ Want to Buy' started by dba, Mar 11, 2012.

  1. dba

    dba Moderator

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    It's not my listing, but someone might appreciate the tip:

    eBay item 400281097623 is for a Supermicro 3U backplane (with the SAS2/SATA3 expander) for a Supermicro 836 chassis. It's $391 with free shipping, which is way too high for a used item, but it's a "make offer" sale and might be available for a reasonable price.
     
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    Last edited: Mar 13, 2012
  2. Patrick

    Patrick Administrator
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    That is basically the new price. Anyone looking at this I would suggest 2 as the first digit.
     
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  3. mobilenvidia

    mobilenvidia Moderator

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    Looking at the picture it's the single SAS Expander Chip model
    SuperMicro also make the dual SAS expander chip version
    More likely single expander backplane offer start with a 1, dual expander start with a 2

    For those even remotely interested:

    Single Expander chip only support cascading, one port from the SAS controller connected to the expander can control all 16 drives
    Your normal every day expander.

    Dual Expander chip has cascading and failover.
    If both expander input ports are used, should one port fail the other port can take over, can be used on a single dual port controller
    BUT if you connect a sas controller to each input then if one controller fails the other will take over all the drives.
     
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  4. dba

    dba Moderator

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    Have you tried a SAS dual expander with single-ported SATA drives? I know exactly how they work with SAS drives but can't find any information about using them with SATA drives. Can you utilize both channels at the same time and do you get failover?

     
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  5. mobilenvidia

    mobilenvidia Moderator

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    I would think they work the same with SATA as with SAS.

    Fallover works when either one port on the SAS controller fails OR if one controller fails if 2 controllers are connected to the expander.
    From Supermicro's explanation of how their expander backplanes work, all ports on the expander are available to either port
    But am not sure if this is at the same time or only if there is a fallover and one controller or input port fails.

    Grab your self any SM case PDF that ends in E26 ie SC836-E26 that comes with the 28 port dual chip expander
    Scroll on down to near the end and here the expander is explained
     
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  6. cactus

    cactus Moderator

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    The SAS 836EL(1 or 2) manual says only SAS drives are supported. For the dual expander, I would expect you need dual port sas HDDs to take advantage of the redundancy. If both expanders were tied to the same port on the HDD side, I dont see how the drive would be addressed. From my understanding the expander acts like a switch and keeps hardware IDs, there is some cool name for them that I cant remember, but it is analogous to a MAC address, and the port it is seen on. It also seems silly to have a single point of failure, HDDs interface controller, if you are putting so much subsystem into redundancy.
     
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  7. mobilenvidia

    mobilenvidia Moderator

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    It's a complicated bucket of bolts this 2x expander chip backplane.

    How would the motherboard cope with 2 SAS controller hooked up to 2x expander chips (1 to each port) that can then see the same drives.
    OR the 2nd SAS controller with the 2nd expander chip off sees no drives until there is a failure on the other port the 2nd expander chip turns on treating the backplane as hot swappable, drives are back online with same SAS address ?

     
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    Last edited: Mar 15, 2012
  8. PigLover

    PigLover Moderator

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    OK, I'll concede on the 9260 since I only had it in my hands to play with for a day or so, but you still need to eat at least half your words...and stop posting that the 9240 (and its OEM brothers like the 9240) does not do passthrough.
     
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  9. mobilenvidia

    mobilenvidia Moderator

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    Not quite sure how this ended up over here.

    I'll eat the lable in my hat, but that is all.
    The LSI9240 (IBM M1015 in default mode) does JBOD, you say this is passthrough.
    JBOD can only be achieved by making sure its set on the controller.
    Drives not set to JBOD (ie even unconfigured good) = not seen by OS

    LSI9211 based cards, no need for JBOD as long as drive is 'Unconfigured Good' the OS can see it
    This to me is proper passthrough.
     
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