RAID set and JBOD on same controller card?

Question

RAID set and JBOD on same controller card?

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 here's what I'm planning (tentatively)

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

I don't have the cash or demand (yet) for a system in a huge expansion chassis and 24 drives, but my the main thing I want to know, (since I've never had this many discs to play around with before) is when I create an 8 disc RAID 5 Array for storage, can I also connect another external chassis to the controller as a JBOD unit and have those drives therein function independently, with swap capability of single volumes? This would be very handy for individual cleint-drive backups and would free up my eSATA interface for file ingest and more flexibility.

I do know I would have to get an adapter to run more than one external SAS connection cause the Card only has one External SAS port as is. I may go with a different card with more channels for more future expansion, but it will more than likely have more internal ports than external.

2009 MacPro 8core, Mac OS X (10.6.6)

Posted on Feb 13, 2011 3:49 PM

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Answer 1

Best reply

l_elephant

Level 2

375 points

Feb 15, 2011 4:05 AM in response to Chris Ratledge

Chris Ratledge wrote:
I'm planning to update my RAID from the current 4-disc software 0 in my MacPro . . .

your system is on that RAID0?
do you regularly clone your system, for when, (not in case), the RAID0 fails?

. . . to a RAID 5 with dedicated controller (for now) and here's what I'm planning (tentatively)

have you considered the added security of RAID6 (if your going to have that many drives . . .)

. . . but my the main thing I want to know, (since I've never had this many discs to play around with before) is when I create an 8 disc RAID 5 Array for storage, . . .

when you mean storage, do you mean like archival, past projects type storage, or current working projects drive space?

can I also connect another external chassis to the controller as a JBOD unit and have those drives therein function independently, with swap capability of single volumes?

yes

I do know I would have to get an adapter to run more than one external SAS connection cause the Card only has one External SAS port as is. I may go with a different card with more channels for more future expansion, but it will more than likely have more internal ports than external.

you're describing SAS expander. You can easily have more than 200 drives connected.

notice the price difference whenever you see 'SAS expander' 🙂
http://eshop.macsales.com/search/SAS

i was looking at this one the other day;
http://eshop.macsales.com/item/EZ%20Quest/E99716/

with its multiple stream 20GB/s. Its apparently daisy-chain expandable.

what kind of work are you doing? Vidéo, audio? One project at a time, or parallel projects? Alone or with others (colleagues, employees)? The Caldigit system looks nice for large teams of people.

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Answer 2

Feb 15, 2011 2:26 PM in response to l_elephant

l_elephant wrote:

your system is on that RAID0?
do you regularly clone your system, for when, (not in case), the RAID0 fails?

Yes, when working I backup the data ideally after every time I add footage to the RAID, if not at least once daily.

have you considered the added security of RAID6 (if your going to have that many drives . . .)

I have, and it will probably be the next step if I go to a RAID larger than 8 discs. IF I do start getting the need for 16+ I may go to a RAID 10.

when you mean storage, do you mean like archival, past projects type storage, or current working projects drive space?

Working projects. Also will look into LTO for archival in the future if the demand necessitates it.

can I also connect another external chassis to the controller as a JBOD unit and have those drives therein function independently, with swap capability of single volumes?

yes

Thank you, this is the main question I had, do you have a specific experience such as this you would share?

I do know I would have to get an adapter to run more than one external SAS connection cause the Card only has one External SAS port as is. I may go with a different card with more channels for more future expansion, but it will more than likely have more internal ports than external.

you're describing SAS expander. You can easily have more than 200 drives connected.

No I'm describing a PCI plate SFF-8087 to SFF-8088 Adapter, like this one:
http://www.pc-pitstop.com/sascablesadapters/AD8788-4.asp

Like I said, most of the cards I'm looking at have more internal 8087 ports than the external 8088 ports.

what kind of work are you doing? Vidéo, audio? One project at a time, or parallel projects? Alone or with others (colleagues, employees)? The Caldigit system looks nice for large teams of people.

This would be a mobile installation, with me as a single operator handling digital video footage, so this would be direct attached storage, no network interface necessary. Usually one project at a time, but if I get busier hopefully more than one.

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