# Supermicro 24 drive chassis - how to build ZFS server?



## Goose997 (Oct 22, 2015)

Good evening

After a long hiatus, I am back on the forum.  Actually, with my ZFS storage server running without problems for years I only needed to browse every now and then.  However, I finally decided to take the leap again and build a proper server (still to be used at home) but with enough hard disks so that I have expansion flexibility.

I am interested in building a server using a 4U Supermicro chassis with space for 24 HDD.  I want to use off the shelf SATA disks.

I was thinking of http://www.supermicro.com/products/chassis/4U/846/SC846E26-R1200.cfm?parts=SHOW  as basis.  My goal is to have minimum extra wiring, I assume this is the chassis that has a backplane that kind of makes it "plug and play".

What else do I need?  I am thinking of a cheap Supermicro motherboard that supports ECC memory, at least up to 32GB.  Do I need still controller cards, or an HBA etc.?  

I have built many high end PC's in my life, but never used server hardware, so this will be all new to me.  Any help (or links) to a parts list / website of a similar build will be very helpful.

Thanks in advance!


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## User23 (Oct 23, 2015)

Start reading the manual for BPN-SAS2-846EL(2) backplane. http://www.supermicro.com/manuals/other/bpn-sas2-846el.pdf
It is a SAS backplane with expander chips which (should) have to be compatible/tested with the HBA and drives you may want to use for ZFS.


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## pboehmer (Oct 23, 2015)

We just built a server using the Supermicro SuperServer 6047R-E1R36N which has the BPN-SAS2-846EL (front) and BPN-SAS2-826EL (rear) backplanes attached to a Supermicro AOC-SAS2LP-H8iR card (included, uses the mfi driver) and we are very happy with it.  Just supply CPU(s), RAM, and drives.


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## Goose997 (Oct 23, 2015)

Dear User23, pboehmer

Thanks for the comments and guidance.  I will do some further reading on the hardware you suggested.


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## phoenix (Oct 23, 2015)

Goose997 said:


> Good evening
> 
> After a long hiatus, I am back on the forum.  Actually, with my ZFS storage server running without problems for years I only needed to browse every now and then.  However, I finally decided to take the leap again and build a proper server (still to be used at home) but with enough hard disks so that I have expansion flexibility.
> 
> ...



We use this with great results.  You don't want the E1/E2 versions, though.  Those use SAS expanders that put 8-12 drives behind a single SAS channel from the HBA.  And the E2 version includes fail-over ports for multi-homing the chassis to multiple HBAs.  There's another version that supports multi-lane connectors, but gives you 1 SATA channel per drive bay.

The chassis comes with a backplane that uses multi-lane (SFF-8087) connectors to minimise the number of cables needed.  You plug a multi-lane cable into the HBA, and plug the other end into the backplane, and that gives you access to 4 drive bays.

We use various versions of this chassis with LSI 9211-8i adapters for ZFS, and 3Ware 9750SE RAID controllers for XFS.

You'll probably want to pick up a pair of SSDs, connect them to the motherboard SATA ports, use them in a separate ZFS pool for the OS install.  That way you can use all 24 SATA drives for a data pool.  If you get big enough SSDs, you can even use the extra space for L2ARC.  There's enough space between the top of the chassis and the drive bays to store the SSDs (a little two-sided tape can be used to secure them if needed).


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## ondra_knezour (Oct 24, 2015)

phoenix said:


> You'll probably want to pick up a pair of SSDs [...] There's enough space between the top of the chassis and the drive bays to store the SSDs (a little two-sided tape can be used to secure them if needed).



Most of the Supermicro chassis I came across had internal option to mount one or more additional non hot-swap drives, usually with some optional bracket. This one have it too, but it is not easy to get this information when you are in position of a prospective customer who just started gathering information about possible purchase. You have to dig into manual for all possible items, because their web is one of the worst I have to use regarding information availability/presentation.

So here you go

```
Position           SC846B Models                Non "B" Models
Position A        One fixed 3.5" HDD          One fixed 3.5" HDD
                       Two fixed 2.5" HDDs        Two fixed 2.5" HDDs
Position B        Two hot-swap 2.5" HDDs  One fixed 3.5" HDD
                       One fixed 2.5" HDD          One fixed 2.5" HDD
                       One DVD drive                 One DVD drive

For 3.5" drives, use the mounting tray, MCP-220-84601-0N.
For fixed 2.5" drives, use the mounting tray, MCP-220-00051-0N,
and attach to MCP-220-84601-0N.
Note: SC846B does not support 3.5" HDD tray in position B.
```
See the chassis manual, page 4-19.

Side note: If someone knows how we can use tables here, PM me a link please.


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## Terry_Kennedy (Oct 31, 2015)

User23 said:


> Start reading the manual for BPN-SAS2-846EL(2) backplane. http://www.supermicro.com/manuals/other/bpn-sas2-846el.pdf
> It is a SAS backplane with expander chips which (should) have to be compatible/tested with the HBA and drives you may want to use for ZFS.


SATA drives on SAS expanders can be problematic (it moves the translation of SAS<->SATA off the controller to a place the operating system can't "see" it). This generally only becomes noticeable when a drive experiences an error. The last thing you want is everything on that expander to drop offline due to funky error recovery.

My rule of thumb is that SATA drives only go on SATA controllers or on SAS controllers without expanders. SAS drives go on SAS controllers, with or without expanders.


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