RAID setup

Hello,

Yesterday I had a lot of problem to play my material into Davinci Resolve 12.5.6 on OSX. I thought it was because of the codec and mix frame rate In fact it was because HDD RAID6 access. I copied my material on a standard USB3 HDD and it worked. So I think the RAID6 setup is wrong..

I'm not in my studio, but at someone else studio, his all new RAID6 system is : LaCie 8big Rack Thunderbolt™ 2

What is the best setup for a RAId6 for Davinci Resolve (Cash size, block size, write back or write through etc...)?

Best

Robin

I'm using a G-Speed Studio XL 8-drive 64TB Thunderbolt2 at the moment, and I believe my settings are:

RAID5
1MB stripe
read/write cache enabled

The drives are WD Red 8TB with a 128GB cache, and I'm getting about 826MB/s write and 1108MB/s read, which is actually better than the 24TB setup this replaced. Playing 4K in real-time is not a problem. With my small ape-like brain, I just accepted the default RAID5 settings beyond this and it seems to work just fine under OSX 10.12.8 so far.

RAID 6 is going to run slower than RAID 5, although you have greater safety. Still I'd never want to actually rebuild a RAID 5/6 system especially one as large as 64TB. I'm a fan of RAID 10. One disk goes bad, replace it, and immediately carry on working.


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I'd never want to actually rebuild a RAID 5/6 system especially one as large as 64TB

It's almost guaranteed to fail. The WD Red drives have an unrecoverable read error rate of 10^-14, which means that for an 8x 8TB setup, you have a 99% chance to fail rebuilding in RAID 5, and 97% chance to fail in RAID 6. WD Red Pro drives have a much better URE of 10^-15, translating into 36% and 11% to fail respectively, but you still have to endure a rebuild even if it works.

Hello,

Thank's for your messages.
Our HDDs are server quality. But the problem is that the access time to the drive seems to be variable. Sometimes it reads material (video) immediately sometime I have to wait 5 seconds, sometimes I have to press play bar 10 times. I put the same material on standard HDD USB3, and it works without any problem. That's why I think the RAID6 setup is bad, and that's why I would like to know the best setup to create a RAI6 array for video.

Best
Robin

Could it be that your RAID has some 'sleep' settings?
Please, don't take this for an offense.

Hello,

Thank's for your messages.
Our HDDs are server quality. But the problem is that the access time to the drive seems to be variable. Sometimes it reads material (video) immediately sometime I have to wait 5 seconds, sometimes I have to press play bar 10 times. I put the same material on standard HDD USB3, and it works without any problem. That's why I think the RAID6 setup is bad, and that's why I would like to know the best setup to create a RAI6 array for video.

Best
Robin

It has nothing to do with RAID6, you simply have some fundamental problem with your setup.
This should not happen and it doesn't really happen when things are working as they should.

You rather want big block size for work with video (specially 4K DPX, EXRs)- you can use biggest choice on the list.

It maybe faulty controller, TB2 issue, drivers or combination of all of them.
Is RAID6 showing healthy status?
Ty different TB2 port- if you are on Mac Pro look at TB2 port layout and connect it to port which will be dedicated just for RAID.
Make sure everything is up to date. Try AJA disk test (not BM one) with big file size and checked detailed graph for performance dropouts.

Hello,

Thank's for your message.
There is no "sleep settings", your question wasn't an offense, don't worry

About strip size
The choice from the list are limited to 256 max. No others options. Strange, no ?

I will try to reinstall drivers and change TB2 port and launch a AJA disk test.

Thank's for your help everyone.

Best
Robin

256K is already fairly big stripe size, so this is not a big surprise. Some controllers offer bigger ones, some don't, usually more expensive ones do bigger sizes (I think).