What SATA RAID5 controller for video editing?

[dan_aka_jack]

Hi there,

I'm planning on building myself a 4-disk SATAII RAID5 setup for video editing. My main question is whether I need to spend loads of cash on a "dedicated" RAID card or whether modern dual-core CPUs can cope with calculating all the RAID5 parity data on their own?

I have found a handful of reviews on the web claiming that you really need a dedicated RAID card for RAID5... but all these reviews are a few years old.

Is anyone out there running a RAID5 array with a dual-core CPU and "non-accellerated" RAID card like the HighpointTech RocketRAID 2300?

Many thanks,
Jack

 

[rpstewart]

The RocketRaid is "accelerated software" rather than fully hardware like the Areca cards, it is however significantly faster than the motherboard based RAID5 solutions.

The read rate of all the cards will be pretty much identical as there's no processing required but the write rates will vary wildly (150-200Mb/s probably):

OnBoard - 15Mb/s
RocketRaid - 45-60Mb/s (this is what I get from a RR2320 with 8 disks & a 4400X2)
Areca - 90-100Mb/s (but £400+ & PCIe 8x )

It's therefore clear if you want writes close to the read speeds then you need to spend a fair whack of cash.

I'm not exactly sure how you do the editing but you could use a mix of RAID0 and RAID5 (which is what I have). Could you use a RAID0 partition, 500Gb from 2x320Gb, as a target for all your writes and then use a RocketRaid based RAID5 array for source files and secure storage of completed projects?

 

[dan_aka_jack]

Hi,

Thanks loads for the reply. Hmm - I hadn't considered using a mixture of RAID5 and RAID0! That's an interesting idea. RAID0 frightens me. A lot. (Even though I currently have a 2-disk RAID0 array!)

Thanks for those benchmarks. Is it reasonable to expect that multi-core CPUs will make "software RAID" a more respectable prospect? If you have, say, a 4-core CPU then you could dedicate one of those cores to RAID tasks and still have a very swift computer.

How do I do my video editing? Mostly I use Adobe Premiere Pro 2.0 and After Effects Pro 7.0. I'm currently using a Athlon XP64 running at 2.4GHz with 3GB of RAM but I have an X2 arriving in the post today from OcUK. Most of my projects are still SD DV (3.7MB/sec) so they don't require huge read and write speeds (just reliability and fauly tollerance). About half my projects make use of uncompressed SD (~40MB/sec) and a small handful of my own little experiments are uncompressed HD and 2k (~200MB/sec!).

My little business is just starting to take off so I'm planning to build myself a 4-disk RAID5 array on my current computer and then - with luck - I'll be able to build myself a whole new workstation in about 6 months.

Jack

 

[dan_aka_jack]

2nd-hand PCI, ATA card

I've been looking around on "the yellow auction site" and I've found that I can pickup PCI / parallel-ATA RAID cards for very little money (dedicated RAID cards with on-board RAM and processor). These seem like a bit of a bargain, especially as pATA hard drives are still a few quid cheaper than their SATA equivalents. My main concern about getting a PCI card would be the 133MB/sec max transfer rate of the PCI 33MHz/32bit bus.

Am I right in thinking that a 4-drive RAID5 array on something like the Highpoint RocketRAID 2300 should achieve almost 200MB/sec when reading? In other words, would a 4-drive RAID5 array easily saturate the PCI bus during reading?

Hmm...

Thanks,
Jack

 

[rpstewart]

Yeah you should be able to get somewhere in the 200Mb/s range as an average from 4 disks so you will saturate the PCI bus with that.