Hi Everyone, 

So I'm used to building desktop pcs and have been for over 20 years, my Unraid setup built in a PC tower enclosure has run out of bays so I'm futureproofing and have bought this 24 bay rack mount enclosure. Logic Case LC-4680-24B-WH 4U Rackmount Storage Chassis https://www.servercase.co.uk/shop/server-cases/rackmount/4u-chassis/logic-case-lc-4680-24b-wh-4u-rackmount-storage-chassis---24x-35-sata-hot-swap---680mm-depth-lc-4680-24b-wh/

Rank mount enclosures and having to connect to back planes is all new to me and frankly I've been researching and reading and have just confused myself even more, I am not sure if I need LSI, HBA, extenders or a combo of those and other stuff and don't even get me started on fully understanding host/target forward or reverse breakout for the SFF-8643 connectors on the backplane!!!

My existing server is SilverStone SST-RV02B-EW which has 5 bays which I extending to 9 bays by using a Syba SI-PEX40064 SATA III 4 Port PCI-e x1 Controller Card taking 4 drives from a StarTech.com 3.5in Trayless Hot Swap SATA Mobile Rack Backplane - 4 Drive Removable Drive Enclosure. 

My Motherboard is ASUSTeK COMPUTER INC. PRIME B360-PLUS which has 6 SATA slots but as I'm using 2 NVME slots for a cache pool which disables 1 sata port.

The mobo has plenty of PCIE slots and don't have anything apart from the existing controller card connected which won't be going to the new server.

 

So hopefully that is all the saliant info now this is where i need help, to my monkey brain it seems like the easiest solution is to by a LSI 9305-24i controller and plug all 24  drives into that ignoring the mobo sata ports, but is that creating a bottleneck or is it over kill or just plain stupid ????

 

Please help me, would I be better with multiple controller cards or one card and an extender or any other options that I know I won't know

 

Also SAS cabling, am I correct in thinking the SFF-8643 ports on the backplane are the target and so please also advise with you solution if I would need forward or reverse cables is applicable.

 

I'm excited to move my server to the new enclosure and shouldn't have any problems with anything else but this controller/LSI/HBA/Extender solution is some kind of mental block!!

 

Thank you in advance to anyone that can help and If i've left something out that is needed to configure the solution let me know

 

The easiest solution is a 9305-24i and 6 SFF 6843 to SFF 6843 cables. The 6843 connection is also used for PCIe these days, but googling I don't find any cables like that, so there shouldn't be an issue there.

 

Next easiest, almost any HBA with a SAS extender. A SAS extender connects to the HBA with a cable, and the rest of the connections are to the case. Depending on the HBA and extender, you'll need SFF-8087 to SFF-8087 to the extender, and SFF-8087 to SFF-8643 to the case, or SFF-8643 to SFF-8643 for all of it, so 7 cables. Although almost any HBA would work, something like a 9300-8i or 9400 with an Adaptec AEC 82885T extender for example. This extender can be put in a slot for power, or attached anywhere and powered with a molex, like the case. The older ones with SFF 8087 I wouldn't buy anymore, because they might eventually stop working with newer computers.

 

Next, future proofing, a 9600-24i. These use a SFF-8654 connection, and you'd need SFF-8654 8i to SFF-8643 cables. These are also used for PCIe, so you have to make sure to get the ones for SAS/SATA, if you connect the wrong ones, your drives won't be found.

 

Most difficult: A mix of SFF-8643 cables to SATA for the mainboard (reverse breakout cables, see here why. SAS cables are bi-directional), plus HBA's or HBA+SAS extender. This is troublesome because if you want to use M.2 some of the SATA ports don't work, plus if you buy SAS drives in the future and plug them in the wrong position, they won't work. Easily fixable if you plug them in a HBA or extender slot, but may make you think the drive is broken.

 

What I did, was go for a 24 port HBA, reason being, if the motherboard fails, I can replace the motherboard, if the HBA fails, I replace the HBA, if the case fails, I replace the case, if the UBS fails, yep, replace the USB, so I don't have to worry about multiple things at the same time (like get a new part, do the cables fit, how many sata ports do I need on the motherboard, etc).

 

As for performance, it doesn't really matter with hard drives, they usually get up to 200MB/s at most, which means that with most newer controllers being PCIe 3 x8 at a bandwidth of about 8GB/s you can connect 40  drives before things start to slow down. If you connect an extender (assuming SAS 3, so 12gb/s) with one cable, it is 4x12=48gbit or 6GB, so about 30 drives.

 

Something to keep in mind, if you want to connect 24 drives, you'll need 6 molex connectors. There are adapters where you can connect one molex to 2-6 so you don't need that many, but that is not recommended, especially since the case already has adapters, and things might melt. Also most power-supplies don't come with that many,  so this is an issue. At the time, seasonic sold separate cables, so I got one of their modular supplies, with a 3xmolex cable and purchased another one from them. If you already have one cable, you can also consider buying a supply of the same brand, usually the cables have the same pinout, but you can measure it with a multimeter if you aren't sure.

 

The most difficult things with a server like this if you're not used to them is potentially more sharp edges, and not knowing if you connected the cables properly, because they can be quite stiff, but on the other hand. you can force a SFF-6843 the wrong way. For the controller, there is a little indentation on the outside of the port, and the cable-side with the lock/lip on it should face that. Most cases should have the lock/lip of the cable to the top.

Thank you Wody, this is amazingly useful and I'll be re-reading this several times over the coming weeks as I look to buy parts and swap over H/W. I do have a Seasonic FOCUS Plus Platinum 550W (80+Platinum, ATX 12V) currently in my SilverStone server which is modular and so adding extra molex shouldn't be an issue. After running a seasonic calculator for the rack I know that at full capacity this PSU is borderline able to handle all 24 drives and a GPU....but after the rebuild I'll probably only be up to 11/12 drives it might be a while till I need to upgrade the PSU....debating weather this is foolish and I should just upgrade now!!

14 hours ago, coldzero2006 said:

debating weather this is foolish and I should just upgrade now!!

If you don't need the full capacity, you could upgrade now. But there is something weird with the case, the pictures don't show any fans, and the description says 3x120, but the case use hotswap-fans, with plastic housings for the fans that you can plug and unplug, and those housings arem't visible either. Also the exhaust fans aren't listed, usually the ones they put in are pretty bad, so getting some isn't a big issue, but still.