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most affordable 24pt SAS2 Expander cards? (w/cables, not chassis/backplane)

Discussion in 'FreeBSD and FreeNAS' started by Twice_Shy, Feb 15, 2017.

  1. Twice_Shy

    Twice_Shy Member

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    I'm specifically looking for an SAS2 Expander for SnapRAID right now - but the plan is in the future to reuse the same hardware under FreeNAS ZFS in the future so i'm asking here, since it sounds like anything under linux should work fine for snapRAID anyway. I'm hoping if it has BSD support it also has linux support and if I understand Expanders it shouldn't even matter on the software/OS at all.

    I am looking for SAS2 Expanders - I looked through the Buying Guides here, and they talk about good HBA's and such, but I didn't see a mention of what Expanders to use. I dont mind Expanders which require PCI or PCIe slots for power, or even slaving some old motherboard to provide power for it if needed as long as the per-port cost is substantially lower. (and prefer the more available PCIe x1 by now of course, or/and wonder if one of those bitcoin risers x1 to x16 could be used for cards that seem to want to sit in an x4 or x8 slot - I assumed there was the same power feed to all cards regardless of lanes afterall) Of course something that stands alone is more flexible/not needing a motherboard to power it.

    I don't need full hot swap chassis with built in cordless backplane whatever - i'm fine connecting cables in existing cases for now. Just need the Expander which will let me hook up drives in ATX cases and i'm happy.

    I see on ebay 24 port SAS expanders as low as $50 - it's not clear if they are SAS1 or SAS2 but I assume SAS1, though some claim 6gbps speed - so i'm not sure if that's the only thing to search for as a term. I don't know whether there are any concern with brands - should an HP or Dell SAS Expander work perfectly fine in anything else? (my assumption is they need no drivers so should) Any to avoid/known problems? Any widely known as reliable?
     
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  2. i386

    i386 Active Member

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    That's becuase many use server chassis where the expander is on the backplane and not an add on card.

    For more information about the sas2 HP expander read this thread HP SAS Expander Wiki

    Personally I would use one of the Intel expander (with an LSI chip) add on cards becuase they can use pcie or molex 4pin for power.
     
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  3. Twice_Shy

    Twice_Shy Member

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    Yes, i'm aware most are built into backplanes. The used chassis+backplanes are costing more than i'd like and i'd rather use my own chassis for now to include 5.25 opticals and such too.

    Most of the cards I see on ebay seem to be SAS1 HP Expander cards. I was wondering if an SAS1 expander can be used with an SAS2 HBA just with the limits of SAS1 speed - or if it would also share the problem with 2TB hard drives and such. I could still saturate 1gigE for now and upgrade when prices come down later. (or it could go in my backup system since I dont have the money to build two 'full speed' systems right now if something were to happen to the main one, and just swap over drive cables if there's a problem)

    Which Intel Expander would I search for? I also see some maker called Chenbro/wondering if anyone besides Intel or HP is worth considering.
     
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    Last edited: Feb 15, 2017
  4. rubylaser

    rubylaser Active Member

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  5. i386

    i386 Active Member

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    Expanders are "active", my guess is that they share the same problems.

    My recommendation is the Intel RES2SV240.

    Chenbro uses LSI expander chips (LSI SASIIX28/SASIIX36).
     
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  6. Tom5051

    Tom5051 Member

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    You don't mention what RAID controller you intend to hook the expander up to.
    Expanders will only work when connected to a RAID controller that supports expanders.
    Since you're talking about snapraid, makes me wonder if you are talking about software raid. In which case an expander will not work, you'd need a sata add-in card with lots of ports.

    The 24 port sas expander will only support 16 drives, the 36 port will only support 24 drives.
    The other ports are for connecting to the controller and daisy chaining to another sas expander.
     
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  7. i386

    i386 Active Member

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    SAS HBAs support expanders.
     
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  8. Tom5051

    Tom5051 Member

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    Not all of them do actually and quite a few brands are fussy with the brand of expander.
    OP makes no mention of HBA so what is your point exactly?
     
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  9. Aestr

    Aestr Active Member

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    If he needs a lot of ports for software RAID as mentioned there are many SAS HBAs that will work just fine with an expander. Whether it's better to use multiple HBAs vs one and an expander comes down to price, free pci-e slots and performance requirements.

    The 24 port Intel expander mentioned above that is always very popular due to availability and price supports 20 drives not 16.


    Sent from my iPhone using Tapatalk
     
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  10. markarr

    markarr Active Member

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    and most of those brands can be reflashed to the base LSI firmware which will work with both the intel and chenbro expanders. The point he was trying to make is that an sas hba in IT mode with an expander can do the same thing as a SATA cards in software raid. There are very few manufacturers of SAS chips so if you have the chip from the same generation and manufacturer it will work (fw flash may be needed).

    I would also recommend the intel expander, I had it behind a reflashed ibm 1015 and had no issues using both ZFS and snapRAID.
     
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  11. rubylaser

    rubylaser Active Member

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  12. whitey

    whitey Moderator

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    LSI HBA (2008/2308/3008 variant) paired w/ a Intel RES2SV240 is what you want for a 'big ole box of JBOD/sw raid' setup.
     
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  13. Twice_Shy

    Twice_Shy Member

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    I'm working backwards, first choose the most affordable Expander, and then choose the most affordable HBA card to go with it, since if the HBA doesn't support Expanders I wouldn't be getting it in the first place. :) Same reason i'm willing to go with PCIe or even PCI Expanders (tho the latter probably dont exist in 6Gb but i'd use one if it was out there for lower $) - I just need to hook a bunch of drives up for cheap. I finally abandoned the SATA Port Multiplier idea entirely when it became apparent i'm going to START with at least 14 drives hooked up by merging several servers into one virtualized server.

    I WOULD like something (in either Expander or HBA) which happens to have an external port handy for an Ultrium LTO drive, I assume I could run an internal cable out through some adapter but if it were built in for even more convenience that's a plus.
     
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  14. Twice_Shy

    Twice_Shy Member

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    Wow! I dont suppose these can work with Expanders as well do they? I'm not against 2 or 3 HBA's, but part of my increasing like for the Expander idea is having the server mobo separate from the drive tower so if there's ever a problem I just swap one cable to the backup mobo unit. However I can grow into that without doing it instantly.

    If nothing else i'm not against adding a second card if I need slightly over 24 drives but not enough for a whole 'nother Expander.

    What are the ups and downs of this specific card? $40 seems very cheap for a 6Gb HBA. I would like to experiment with both SnapRAID and FreeNAS ZFS, I might alternately put a spare card in another PC/even if I have one good card recommendation for the main system, I might put SAS cards in other systems even if just to plug in and use my Ultrium drive directly at other times. (or I might suggest the card for a friend who wants to use the LTO drive as a loaner on occasion)

    EDIT: Also searching I stumbled across this article How-to Flash Dell Perc H310 with IT Firmware To Change Queue Depth from 25 to 600 - ESX Virtualization which is probably already known but I guess that Dell is an LSI chip and can be given enhanced abilities with a flash? What are the advantages/disadvantages of this card vs the Intel or HP cards?
     
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    Last edited: Mar 3, 2017
  15. Terry Kennedy

    Terry Kennedy Well-Known Member

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    They probably do, at least with Dell expanders. For example, the Dell R510 / NX3100 are a 12-bay storage chassis which use a PERC H700 (higher-end card of an older generation), which only has 8 SAS ports (on a pair of SFF-8087 connectors).
    If you are using SATA drives I suggest additional controller ports instead of a SAS expander. SAS expanders do the SAS / SATA conversion for attached SATA drives, which hides things from the controller (and thus from the host OS). It is also very hard to find updates for expander firmware, so you're likely stuck with whatever it comes with.
    There are 2 kinds of LSI OEM controller cards - cards which are 100% the reference design, or which are actually the generic card with a "bumper sticker" that says HP, etc. These may have slightly different firmware, but the hardware is exactly the same. These should perform just like the generic card when flashed to generic firmware.

    The second type are cards which have been customized by the OEM. There won't be a generic card that is exactly the same (if there was, they'd just use that instead of designing a custom card). While these cards use generic LSI chips and can be flashed with generic firmware, some things will either work differently or not at all. For example, the "Dell 6Gbps External SAS HBA" has a pair of dual-color (amber/green) LEDs, one for each external port. The generic firmware doesn't know about these, so they are always amber. The Dell firmware uses off: no device connected, amber: at least 1 but less than 4 lanes connected, green: 4 lanes connected. The various Dell internal SAS controllers have support for the Dell SAS backplanes as well as alerts to the front panel LCD. None of that is available when those are flashed to generic firmware (and you may not care, if you're using the card in a non-Dell system anyway). I have heard about (but don't have first-hand experience) that the port numbering changes on one model of HP card depending on what firmware is flashed. This is (IIRC) a 4i4e card, so this can be particularly annoying.
     
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  16. TType85

    TType85 Active Member

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    FWIW: If you can mount it in your chassis (I have a p4000m) I was able to do a BO of $80 for this RES2CV240 Intel RES2CV240 SG27402 RAID Expander 6 Gb/s SAS/SATA NEW BOARD ONLY, NO ACC. | eBay I already have cables and standoffs are not an issue so this is cheap to help clean up the cables. I have the 2x8 2.5" and 1x4 3.5" HDD mounts in my P4000m case so that is a lot of cables running to the H310 HBA's and motherboard.
     
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  17. Twice_Shy

    Twice_Shy Member

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    I was under the impression the Expanders "just worked" but apparently there are potential compatibility issues as well, at least for full functionality. (wondering how much that functionality matters/most concerned about every drive being accessible is all)



    BO/bulk order, so you are reselling something?

    I'm still in the research and not ready to buy (realizing I still dont fully understand what I thought I did) but hopefully soon when I understand better what the different alternatives are I will be willing to commit.

    FWIW whether multiple HBA's or SAS Expanders i'm still interested in learning the ins and outs of doing it both ways. Expanders seems the best way to connect 17-48 drives still (don't see many motherboards that can take multiple HBA's except the dual x16 SLI/crossfire type boards and even those are an extra cost) and possibly just 9+ at all due to cable neatness. Everything is still open as an option (from using PCIe expander cards, Molex powered separate Expanders, and a single monolithic case with server mobo, drives, and 3x HBA's) with my main goal still being minimum overhead cost per drive in the total aggregate sense since i'm mostly pretty well set on what i'm needing to build by this point.

    Pretty much designing around 16-32 drives (which itself doesnt map up easily to only one 24port expander) and preferably having the drives separate from the server, so that if the box dies I can just attach the backup cold swap server to the existing drive chassis (not hot swap though - am able to power down if a drive dies for now but that's okay) with 1-2 cables and call it done. Also makes hardware upgrades easier.

    However that is just the first box - I will be building more than one setup for others (some less demanding maybe 8 drives, others possibly more) whether they do an identical setup to mine, or whether there is a clear point where it makes more sense to go Expander over multiple HBA likely based on # of drives and total system cost en totale. Third to a half of a petabyte is likely going online under my watch but more likely to be distributed between multiple systems instead of a single monolith at this point and some of that is reusing older drives so it's more connections than you'd need for brand new setups with fresh 10tb drives.

    EDIT: One important point worth adding, i'm looking for Expanders which wont only work with one card/I wasn't aware they had individual firmware update issues but now that I know that, i'll want something that can work with more than one HBA for instance (if that is an issue), which works best cross-platform, and similar. I'm still struggling to understand what is different about each of the Expander options right now (let alone HBA's).
     
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    Last edited: Mar 12, 2017
  18. RyC

    RyC Active Member

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    BO is best offer, kalleyomalley is known for accepting a best offer price well under what it's listed for on eBay
     
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  19. Twice_Shy

    Twice_Shy Member

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    So is $80 about the 'real' going rate for them or has anyone scored any for less? :) Or offered less and been refused? Or got less in the past but refused now?

    That board may be my first choice due to being molex powered so I could mount it in a separate drives case without any motherboard. Cost per port $80 for the expander vs $40 for that Dell HBA makes the Expander cheaper per port again. (also makes me wonder could I use the Intel expander just fine with that Dell HBA?)

    What are the downsides of either? This seems to have mostly narrowed my choices pretty well... i'm hoping these could work for all situations (linux, BSD, windows) and I might just buy several of each for setting up several server boxes and drive cases. Any other viable alternatives for either? Going once... going twice...
     
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  20. TType85

    TType85 Active Member

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    I usually go around 1/2 what that seller has listed I got a reasonably quick reply to my offer. You may be able to go lower. I have purchased a good amount from them so YMMV. I will be using the expander with a H310 flashed to the LSI firmware. The PCIe version of the expander worked fine with a H310.

     
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