What controller / expander differences?

[achalmersman]

Sorry I'm a newb even though I've been using unRaid several years.  I'm transfering my server from a stormtroooer CM case to a Norco 4224.  Currently all 5 drives are connected to the motherboard but since I only have 6 onboard SATA connectors I'm going to need a controller or 2 for the other 5 backplanes.  I see controllers and I see expanders.  What is the best performing most cost effective option for me?  Can unRaid use just expander cards or do they have to be hooked to a controller?

 

I have 2 pci slots, 2 pci-e x1 slots, and 2 pci-e x16 slots.  Obviously I would rather leave a x16 slot open in case I ever want to run a video card in the future.  Also, all my drives are equal to or greater than 3 TB

 

Help a newb out.  What should I buy.  Thanks guys

[garycase]

First, a controller provides actual SATA ports.    A port expander allows you to use one SATA port to connect multiple drives.    Note that this means the bandwidth of that single SATA port is being split among all of the attached drives -- so the performance will be degraded for any operation that uses multiple drives on the same expander port (e.g. parity sync/checks and drive rebuilds).

 

Second, you don't want to use PCI controllers, due to the PCI bus bandwidth restrictions, so you're limited to the PCIe slots.  If you want to preserve an x16 slot for a video card, that means you can use one x16 slot and the two x1 slots.

 

The best approach that won't restrict your bandwidth would be to buy a 16-port card for the x16 slot, and a 2-port card for an x1 slot ... this would give you a total of 24 ports (matching the case's capabilities).    A second 2-port card would give you a couple extra ports if you want a port for pre-clearing and perhaps an internal SSD.    You could also use 4-port cards on the x1 slots, but that would be bandwidth limited if you used all 4 drives at once.

 

[achalmersman]

Thanks for the help!  Would something like this be advisable for the 16 port card? 

 

http://www.newegg.com/Product/Product.aspx?Item=16-124-076

 

I can do more searching now that I know I need a controller and not just an expander.  Thanks for any and all help! Andrew

 

[JorgeB]

That controller is pcie 4x, it will limit your max parity check / sync speed to ~100MB/s, while not bad you decide if it's acceptable for you.

[garycase]

As Johnnie noted, the card will impose some bandwidth limits during parity checks (and syncs) and drive rebuilds, since it's a 4-lane card.    It IS a v2 card, so 4 lanes will give you 2GB/s of bandwidth ... but that's only 125MB/s each if you have 16 active drives (and you'll get somewhat less than that theoretical max in actual use).

 

Nevertheless, it's a nice card for the money -- most PCIe v2 x8 cards that support 16 drives cost well over twice as much.  I did find this card for not a lot more than's PCIe v2 x8:  http://www.newegg.com/Product/Product.aspx?Item=N82E16816118142

 

This would eliminate any bandwidth bottleneck for attached drives [unless you use a lot of SSDs].

 

 

 

[achalmersman]

Awesome.  Thanks for the info guys!

 

So could a person use an expander card in a pci slot for power and use a sata 3 port on the motherboard?  8 drives to 1 sata 3 would be 700 mb/sec right? Or am I thinking about it wrong and that isn't done?  Just trying to learn.

 

I'll probably start by purchasing that card in your link.  I assume it's known to work with UnRaid?  I can look in the wiki

[garycase]

Awesome.  Thanks for the info guys!

 

So could a person use an expander card in a pci slot for power and use a sata 3 port on the motherboard?  8 drives to 1 sata 3 would be 700 mb/sec right? Or am I thinking about it wrong and that isn't done?  Just trying to learn.

 

I'll probably start by purchasing that card in your link.  I assume it's known to work with UnRaid?  I can look in the wiki

 

You don't need ANY card for power => you connect the power connections to the power supply.  You may need a few power splitter cables -- but none of these have anything to do with the controllers or any of the motherboard slots.

 

[dikkiedirk]

Awesome.  Thanks for the info guys!

 

So could a person use an expander card in a pci slot for power and use a sata 3 port on the motherboard?  8 drives to 1 sata 3 would be 700 mb/sec right? Or am I thinking about it wrong and that isn't done?  Just trying to learn.

 

I'll probably start by purchasing that card in your link.  I assume it's known to work with UnRaid?  I can look in the wiki

 

Might try to get an Areca 16 port card of ebay.

 

http://www.ebay.de/itm/Areca-16-PORT-PCI-E-SATA-II-Controller-Card-2GB-Mem-Battery-ARC-1261-ARC1261D1-/181949404290?hash=item2a5d079482:g:2bEAAOSwBahVBzBy

 

or similar.

[achalmersman]

Well I bought that controller garycase linked.  Man that thing is awesome.  I don't have it loaded up like you guys yet though.  But I just plugged it in and everything worked.  Absolutley no configuration. UnRaid saw the drives. 

 

Man these norco 4224 fans are noisy monsters but man do they move some air! Ran a 4TB parity hottest drive got to 28°C.  Ran parity check on 5 drives, and a preclear on a 6th.  Parity averaged 114 MB/s (it was 140 ish when I watched before going to bed) and the preclear is running 156 MB/s and the disk temp is 22° after 15 hours.  I might look into less or quieter fans as obviously it's overkill.  But it's going in the basement so maybe I don't care.

 

Thanks for the help guys! Your awesome

[garycase]

Looks nice.  As for the fans .... many folks replace the fans with quieter fans, but as you've noted the temps are maintained VERY well with the stock drives, so if it's going in a room where the noise isn't a factor (e.g. basement) you may want to just leave them alone.    If you've ever been in a server room you've probably noticed that the fans are LOUD ... that's because they choose cooler drives in the tradeoff between drive temps and noise.