First Hardware RAID build - advice?

[Chris Ratledge]

Greetings all.

I'm planning to update my RAID from the current 4-disc software 0 in my MacPro to a RAID 5 with dedicated controller (for now) and I have a few questions, hopefully those here can reflect their experiences, here's what I'm planning (tentatively)

•*RAID 5 consisting of 8 1TB discs, 4 inside 5.1 MacPro with MaxUpgrade's kit in use for SAS connectivity {MaxConnect link} , and 4 more in a rackmount SAS chassis, possibly OWC's new 'trayless' unit, ({Mercury Rack Pro link} or another similar chassis.
•*Areca RAID controller ARC-1880ix-12 is what I'm leaning towards at this time, {NewEgg product link}

I don't have the cash or demand really for a bitchin' system with an expansion chassis and a 16-drive RAID, but I do want to know, since I've never had this many discs to play around with before, if I can create an 8 disc RAID 5 Array for storage, can I also use another one of the Mercury units as JBOD client Drives, connected to the same Areca controller via another external connection? This would free up my eSATA interface for ingest through a RED Station. Obviously I want to figure this kind of stuff out before I pony up the dough.

I would have to get an adapter to run more than one external chassis connection if the above JBOD client drive connection is possible, which takes up a valuable PCIe bracket space in the back of a MacPro already crowded with a Rocket card, eSATA HP Raid card, and GT120. I could lose the SDI output of the Rocket for this sake and just run a DVI from my Rocket to my preview monitor, (doesn't include audio, does it?) but then I'm totally out of space before I have to start making big holes in the MacPro's chassis. (which is probably inevitable anyway, as I'm thinking of hacking the handles for rack-mounting)

Lastly, what would be the recommended PCIe compromise. I don't have the option to do 4k preview with the monitors at my disposal, so i'm leaning towards putting the Rocket in one of the 4x slots, but I don't know if that would be worse than putting either the 8x RAID controller or the GT120 in one of the 4x slots. Anybody experimented with this to see what kind of hit you take on Transcode speed? (I'll try this myself on my system as well just to see, but anyone else's input is worth asking)

Thanks.

 

[Alexander Ibrahim]

Put your video card in your fastest slot... unless you are building a server.

A single PCIe 2.0 lane is 500MB/s.

The 2009 Mac Pro and later have 2 x16 slots and 2 x4 slots.

http://support.apple.com/kb/HT2838

So the slowest slot is a 2000MB/s slot.

So... every slot in your Mac Pro will outperform an 8 SATA drive RAID 5.

As far as the RAID set up goes... if you are pinched for cash check out Drobo. $800 gets you a 5 bay external box with eSATA, FW800, USB3.

It will saturate that eSATA 3 link, which is pretty good for a 5 drive array.

It's cheap its easy and will leave your internal drive bays free for whatever.

 

[Chris Ratledge]

Thanks Alexander, clarification on the slots helps, but I'll still do some testing on my own to see any difference that may exist in practice for my own.

I've thought about and ruled out the Drobo. It's use (or any other eSATA RAID box )would then take away the effectiveness of using the eSATA interface on my machine for RED station ingest. That's why I'm wondering about doing a JBOD chassis the way I'm asking about, connected to the same RAID controller as an 8-drive RAID 5

 

[Alexander Ibrahim]

I've thought about and ruled out the Drobo. It's use (or any other eSATA RAID box )would then take away the effectiveness of using the eSATA interface on my machine for RED station ingest.

You may want to go SAS for other reasons- but that particular reason makes no sense.

Are you using one of those SATA to eSATA bridges to use your internal SATA port as eSATA?

Perhaps you have an older/cheaper 1 port eSATA card?

Maybe you don't know about eSATA port multiplication (aka PM)? That's a feature that allows you to access up to 5 SATA drives using 1 eSATA port. Not all cards and enclosures support PM

I strongly urge you to look at cards like the Firmtek 2ME4-E which has 4 eSATA ports, and port multiplication. All 4 ports will run at full speed in any PCIe x4 slot. Using port multiplication you can hang up to 20 drives (in four enclosures) off these cards.

I'm considering a newish G-Tech card... but I haven't read many reviews on it. Its a lot like the Firmtech, but it supports RAID. Handy if you want to make a RAID of RAIDs.

http://www.bhphotovideo.com/c/product/610409-REG/G_Technology_G_SPD_ES_RC_4_Port_PCI_Express_x4.html

With both these cards, you will also be able to hot swap the eSATA, unlike when using a bridge to the Mac's internal slot.

The downside is that you will not be able to boot from the eSATA.

The new 6G eSATA cards are just coming to market.

There are a few 2 port eSATA 6G cards out there, but I'm not thrilled with those. They don't seem efficient. I'd prefer a 3 port PCIe 2.0 x4 card. That would more fully utilize the 4x slot.

Right now, I don't see any 6G eSATA enclosures- but they will arrive in droves soon.

I might consider SAS because it can deliver 600MB/s TODAY. It costs a lot more to achieve that, but if you need it NOW, well then, you need it now. For my part I intend to wait until eSATA 6Gbps is more diffused.

One downside to SAS is that the controllers need an x8 PCIe slot. On newer mac Pro's that means you will use up a x16 slot... no second video card for Resolve etc.

That's why I'm wondering about doing a JBOD chassis the way I'm asking about, connected to the same RAID controller as an 8-drive RAID 5

I don't know... maybe I misunderstand the parameters of the question.

You want a fast cheap RAID set up right? Add in some cheap JBOD, right?

Here are a couple of 3Gbps port multiplied eSATA cases that may interest you.

http://eshop.macsales.com/shop/hard-drives/RAID/Desktop/

http://eshop.macsales.com/item/Sans Digital/TR5MB/

I think eSATA is the way to go right up until you decide Fibre Channel makes sense. I haven't done the research and math to figure out exactly what the crossover threshold is... but because of eSATA 6G it involves stepping up to Fibre Channel 8G, and seems to cost an order of magnitude more.

SAS used to be more interesting. Perhaps it will gain a new lease on life with PCIe 3.0.

 

[Chris Ratledge]

I don't know... maybe I misunderstand the parameters of the question.

You want a fast cheap RAID set up right? Add in some cheap JBOD, right?

No, not exactly.

1) I want to utilize the 4 internal drive bays of my MacPro (while I have it) as part of a Hardware RAID, and add (for now) an additional 4 drives externally in a separate chassis. While I never looked at SATA RAID controllers for this, going straight for SAS, I could look into it.

2) I want to know if a JBOD chassis can ALSO run independently of the RAID, connected to the same controller, with hot-swap capability. From what I've read in other sources elsewhere, this has been answered positively, so really this is moot by now. I just wanted to try to clarify my question to you one last time.

I appreciate your willingness to help, but I don't know if I ever got across to you what I was specifically asking, so I'll just stop after this post. Thanks for the information, hopefully it will be additionally helpful to others reading it in the future.

 

[Alexander Ibrahim]

Well I am glad to hjelp, and your additional explanation was helpful.

Why is it important that you use the internal SATA slots of the Mac Pro as part of the RAID ?

How are you going to boot the system? Only the internal SATA ports can boot the OS (Or OS X server if your network is configured for that)

I usually prefer to use my internal SATA slots as Apple intended. I have a system disc, a second disk for data, and two drives in a software RAID-0.

I usually do my work using RAID via an HBA ... usually an eSATA with port multiplication.

I think what you could use is a pair of JBOD chassis with eSATA port multiplication, then an eSATA card with hardware RAID.

Check these chassis out:

Sans 5 Drive

Sans 4 Drive

OWC Mercury Elite QX2

I think either of the Sans chassis would work nicely coupled with the G-Technology Raid eSATA I mentioned above.

The OWC Mercury chassis has been well reviewed, and has other i/o options that seem a good value.

I think you could aim for RAID 50 this way, and get similar speed to what you are planning with a bit more redundancy.

So, would that work for you? an 8 or 10 drive RAID 50?

This setup uses 2 of the 4 eSATA ports on the card... which leaves you a port for another chassis if desired and a port for the various Red media readers.