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mdoane
12-30-2012, 01:21 PM
Hey guys, just got my ARC8050 in and I love it so far. I'm curious how everyone else is setting their unit up. Mine has eight 2TB drives, and I'm formatting them to RAID5 right now. Tried RAID6 the first time, but performace wasn't as high as I hoped. Was writing over 600 MB/s, but reading under 300 MB/s. Anyway, I've always used RAID5 in the past with good results, but I've been reading that it's riskier with the today's large capacity drives (http://www.zdnet.com/blog/storage/why-raid-5-stops-working-in-2009/162). I doubt that applies to me since I'm not setting up a mission critical RAID for bank data or whatever. I'll mainly have video and graphic files on mine. While being redundant is important I'll have masters backed up to the cloud as well. Thoughts?

Damien
12-30-2012, 03:21 PM
That article is 6 years old now…

mdoane
12-30-2012, 03:41 PM
That article is 6 years old now…

Does that make it wrong? Dell and other storage providers stopped recommending RAID5 in the last few years.

Damien
12-30-2012, 05:42 PM
No it doesn't make it wrong but it was based on old data and old hardware. 6 years is ages in tech terms. I wasn't trying to dis the article, only point out that maybe some newer data would apply to the newer hardware we now have. The conclusion may still be the same or it may not. Rick would be the one to ask about that, he'll be along in a few.

Also new members get held in the moderation queue (if they post links) for approval. I wanted to get this post 'live' as soon as possible. The easiest way to let you know it was now 'live' was to post a reply and the age of that article, I thought needed to be pointed out for anyone interested in this subject. I meant no offense. (emotion and intent are so hard to convey in text)

Welcome to Macgurus

mdoane
12-30-2012, 05:54 PM
None taken. I'm simply looking for the best setup for my situation. I've heard that this article is accurate, and I've heard that it's rubbish.

unclemac
12-30-2012, 08:25 PM
My take:

RAID 6 allows two drives to fail, and still have 100% up time (at reduced performance). Great for servers that need 24/7 uptime.

For those who need max performance, and large single volumes, RAID 5 would be a better choice. Better performance, and utilizes your HDs better.

No matter if you are running a High Availability server, or a large video/photo volume on an editing station.....you need to have at least one backup of all your data. So if you have a backup, do you really need 24/7 uptime? Is it worth the cost in performance and drive utilization?

I say no.

I would go RAID 5, and solid backups. I have only ever used a RAID 6 where I had servers that could never be down, and were co-located, so it could be days before we could swap drives.

The other option is RAID 5 plus a hot swap spare. You lose a drive....it is always spinning and ready to take over if a drive fails. The RAID will be degraded (slower performance) during the rebuild, but will be full RAID 5 performance while running without issue.

I would not do this on a workstation; I would buy a matching extra drive, and have it on the shelf. Drive fails, you swap. Done.

If your backups are solid, and you have a method to keep them current, RAID 6 has a very limited value, IMHO.

ricks
12-31-2012, 12:29 AM
RAID6 is purely for uptime on a high usage server.

No matter the RAID, the important consideration is the backup. On a workstation, with a backup, a RAID6 is just a waste of performance and storage space.

RAID5 is plenty good stuff. Particularly at the Enterprise level that ARECA takes their hardware and software. You got a great setup.

Rick

mdoane
01-02-2013, 09:50 AM
Thanks for the input guys! I've got it up and running in RAID5 with a spare drive on the way to keep on the shelf. It's running great reading and writing over 500 MB/s most of the time.

ricks
01-02-2013, 10:18 AM
What are you using to test speeds? In all our tests, with about any standard RAID setup, 8 drives, RAID5 or 6 speeds were always over 600 MB/sec. RAID6 shouldn't impact performance much at all.

The only time I ever saw 300 was with 4 drive RAID5 arrays, and even those were closer to 400 when the array was empty.

Rick

mdoane
01-02-2013, 10:29 AM
I'm using AJA System Test and Blackmagic Disk Speed Test with pretty much the same results. See results below.The unit is 8x2TB drive RAID5. The 300 MB/s result was during my first, RAID6, setup.

http://i.imgur.com/gcS1z.png

ricks
01-02-2013, 11:43 AM
Here's 8 drive RAID5, with 2TB Seagate 7200.14s on my MacBokPro.

mdoane
01-02-2013, 11:51 AM
Weird. I've got the same setup, but i'm not getting those speeds. Posted results earlier, but I think a mod has to approve my post first. Anyway, just ran the same test you showed and I got 575 MB/s write, and 648 MB/s read.

ricks
01-02-2013, 01:10 PM
Some set up questions are in order.

Did you set up a standard RAID5, no spare?

Single 14TB volume on desktop?

Mac OS Extended?

Volume mostly empty still?

Other attached Thunderbolt devices?

What computer?

mdoane
01-02-2013, 01:18 PM
Did you set up a standard RAID5, no spare?
Yes


Single 14TB volume on desktop?
Yes


Mac OS Extended?
Yes. Mac OS Extended (journaled)


Volume mostly empty still?
Yes. Just over 1TB of data on it.


Other attached Thunderbolt devices?
None


What computer?
http://i.imgur.com/go7SX.png

ricks
01-02-2013, 01:31 PM
Interesting. Did you use 64 bit LBA for large volume support? I only ask since that is what I have always used/tested with. In old days of MRAID Utility that was only greater than 2TB volume support choice.

Grasping at straws a little. I never got anything significantly different than the high 6 - low 8 numbers off the MBP. I'll have to ask ARECA techs what they think. Those aren't bad, just not what I got.

R

mdoane
01-02-2013, 01:36 PM
Yep, I used 64-bit LBA. There was another option, but I didn't know anything about it so I went with 64-bit LBA. I also used 128kB stripe sizes since the volume will mainly have large video files.

And honestly, I can live with these speeds. It's pretty amazing.

ricks
01-02-2013, 02:30 PM
I'll bet you get faster speeds at the default 64k block size. That by itself may be the biggest (maybe even only) difference in our testing procedure. When I get a chance Ill try it with the larger block size and see what it does here.

Thanks!

Rick