BPN-SAS2-826EL1 - $36

Discussion in 'Great Deals' started by forroden, May 12, 2018.

  1. forroden

    forroden Active Member

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    Just in case any of you happen to have some old CSE-826s you want to retrofit into this decade and don't mind only having SAS2 I found this on eBay today:
    SuperMicro BPN-SAS2-826EL1 12 Bay SAS/SATA Expander Backplane

    There are plenty of A and TQ options available for similar prices (well not A so often) but this is by far the cheapest SAS2 backplane I've seen for these boxes in the last 6 months.

    Oh, and it's got best offer available.
     
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  2. BLinux

    BLinux cat lover server enthusiast

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    wow, that's free shipping and taking BO too... nice deal!

    although, for $40, I would prefer the 826A backplane:

    SuperMicro BPN-SAS-826A 2U SAS / SATA Hard Drive Backplane | eBay

    I like the "A" backplanes as they turn on the LED for SATA drives too, while the SAS2-826EL1 doesn't turn on LED for SATA drives; only for SAS drives.
     
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  3. forroden

    forroden Active Member

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    Yeah I agree, I do prefer the A frames as well, but I ran out of PCIe slots on a box and this is cheaper than most expanders.
     
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  4. Cybertron

    Cybertron Member

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    So I recently purchased this, and am somewhat new to supermicro servers.... Can anyone tell me which backplane would be better? I have the one in the OP, but the A frame one mentioned... would that be better? My intention is freenas + some vm's

    2U Supermicro X9DRD-7LN4F-JBOD 12 + 2 Bay Server 1 E5-2620 V2 | eBay

    And the RAID controller i'm using for external drives: Adaptec 78165
     
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  5. darkconz

    darkconz Member

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    SAS2 expander. If you are running spinners, it does not make much difference. However, if you are running all flash then the A frame is preferred.


    Sent from my iPhone using Tapatalk
     
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  6. BLinux

    BLinux cat lover server enthusiast

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    I have one of those machines too, and it's nice that you can control 12x HDD with a single SFF-8087 connection. With 4x SAS2 lanes, that's 24Gbps total bandwidth which is quite adequate for many use cases. The 826A backplane would require 3x SFF-8087 connections to manage 12x HDD so it requires more SAS hardware (HBA, RAID, etc.). However, it gives you direct point-to-point connections to each hard drive instead of through a SAS expander; theoretically this should give you more performance capacity if your setup (HDD/SSD and SAS controller) can make use of it. With the fastest HDD maxing out around 200~220MB/sec, 12x gives you 2640MB/sec or about 20.6Gbps so that is still below the 24Gbps of the SAS2 expander backplane. So, it would be very hard to take advantage of the 826A unless you are using SSDs. Other advantages of the 826A backplane are:

    - since it is direct connection, your link speed only depends on the end-points. Use a 12Gbps (SAS3) SSD and HBA/RAID controller, and you will link at 12Gbps. With the SAS2 expander, you are limited to SAS2 (6Gbps) speeds. this gives you an upgrade path later on should that matter (mostly if you are using SSDs).

    - the "A" backplanes LEDs light up when the hard drives spin up and flicker when there is activity. this makes it very obvious the hard drive is working. with the SAS2 expander backplanes, when using a SATA drive, the LED does not light up, but flickers when there is activity ; this can give the false sense that the HDD isn't working until you see activity on the drive. Using SAS HDDs, the LED lights up when it powers on the HDD, and flickers when there is activity; so the behavior is different based on SATA vs SAS HDD you are using. I've also heard, but haven't verified myself, that with some SATA SSDs, the LED behavior differs too.
     
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  7. Cybertron

    Cybertron Member

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    Thanks guys, thats what I needed to know. All my drives connected directly to the chassis will be spinners, 8TB WD Reds chucked from last years crazy round of cheap drives. So I should be fine there. My add-in card will be for drives in another 16 bay chenbro chassis, externally connected, and will be direct connected so i can place flash drives there, but likely not something i will do for some time. My pockets are deep enough for a flash array just yet.
     
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