RAID 5?

I've been told that I should not have my 8TB's of storage set-up as RAID 5. Not good for video editing, is this true?

What's the rationale behind that? If it's the URE count on SATA disks, I don't think that is much of an issue, as good RAID controller cards have ECC technology in place to verify the data.



www.strypesinpost.com

RAID 6 gives you more reliability than RAID 5. RAID 5+1 is better still. There's a cost-benefit tipping point.

Some people don't recommend either RAID 5 or 6 - personally I run both and they are a very commonly used for Video.

There is an interesting article here by Art S. Kagel who is Chief Technology Officer for the consulting group Oninit - specializing in supporting IBM Informix databases who recommends RAID 10 over RAID 5.


Like Jeff said there are cost/benefit drawbacks to every different type of RAID level.

5+1 is two RAID 5s Mirrored so you have to factor in that the cost is double for the storage you require; on top of the disk redundancy in each RAID 5 array.


At this point I would say.

If you back up all your RAID data and are happy with the cost/performance of the RAID 5 then there is little reason to change.

If however you do not back up then start immediately!

If you are on the market for a new RAID and can afford it then Jeff's suggestion of a RAID 5+1 is a good one or Art's suggestion of RAID 10 is also good.

---

If you went RAID 10 then its something like this for an 8x1TB HDD Array


Mirrored Set 1 (1TB + 1TB) = 1TB

Mirrored Set 2 (1TB + 1TB) = 1TB

Mirrored Set 3 (1TB + 1TB) = 1TB

Mirrored Set 4 (1TB + 1TB) = 1TB


Make sets 1, 2, 3 & 4 into a RAID 0 (Striped Array)


Total Storage: 4TB

Speed: approximately that of a 4 HDD RAID 0

Redundancy: 1 disk in each set can be lost and the RAID will continue

For better redundancy (but more expensive) make 3 disk Mirrored Sets and you can lose 2 disks in each set. You would need an additional 4 HDDs on the example above.

---

If you went RAID 5+1 then its something like this for an 8x1TB HDD Array


RAID 5 set 1 (4x 1TB - 1TB reserved for redundancy) = 3TB

RAID 5 set 2 (4x 1TB - 1TB reserved for redundancy) = 3TB


Make sets 1 & 2 into a RAID 1 (Mirrored Array)


Total Storage: 3TB

Speed: approximately that of a 4 HDD RAID 5

Redundancy: 1 disk in either set can be lost, plus ALL of the disks in the other set can be lost and the RAID will continue.

For better redundancy make RAID 6+1 but then you have only 2TB available (without adding extra disks) and the speed would drop too.



For instant answers to more than one hundred common FCP questions, check out the LAFCPUG FAQ Wiki here : [www.lafcpug.org]

Thanks everyone for weighing in here. Ben I appreciate all the breakdowns you posted, great info man.

I have been having trouble with my RAID 5 8TB system dropping frames and the tech was telling me I should have set it to RAID 10 since RAID 5 isn't very good for video editing. I just needed to hear from some people on our side of the fence what the thinking was on RAID 5 (HUH?). I have never heard anyone in the post world say RAID 5 was not the way to go. At this point I have a new replacement system on the way and will take it from there. The other thing they were telling me was to maybe go with RAID 0 and continuously back up my files every day. I'm thinking that may have been a reach for new sales though!

Rich

Dropping frames? That's not normal. What codec/machine are you editing on? How much RAM do you have? What sort of RAID? Single controller or double?

It really depends on your set up. If you're working with tapeless, you'd want to have a second storage for the tapeless rushes and an LTO deck for archival. With RAID 10, you'll have half the amount of storage, as compared to x-1 no. of disks on a RAID 5..

RAID 0s is just freaky. Let's be frank. You won't back up regularly. Not when you're rushing for deadlines. It's just not going to happen.



www.strypesinpost.com

I gotta agree with Gerard here - a RAID 0 on its own without a simultaneous backup is a very bad idea.

If your RAID 5 is dropping frames its likely to be another issue as G allures rather than simply RAID level.

As I said I used both RAID 5 and RAID 6 on 2 of my RAIDs and both work around 650 to 800 MB per second and I get no dropped frames.

Give us a detailed breakdown of your RAID and also your system and what you are experiencing the dropped frames on. We might spot something or be able to help sort out whats wrong before jumping ship to another solution.



For instant answers to more than one hundred common FCP questions, check out the LAFCPUG FAQ Wiki here : [www.lafcpug.org]

Sounds like your tech has some very old info. Back in the day, RAID 3 was strongly preferred over RAID 5, for performance reasons. Sequential read was better on RAID 5 because it could ignore the parity drive ? or something. I forget the details. This was fifteen years ago.

These days, drives, buses and controllers are faster, and data rates are lower thanks to compressed intermediate formats like ProRes. It's a rare RAID 5 array that can't sustain at least two streams of ProRes at 1080i60.

Out in the Real World, large framestores are almost always RAID 50, with multiple RAID 5 LUNs striped in software. My current toy is a Promise VTRAK with sixteen drives and two dual-port controllers. There are two seven-drive RAID 5 LUNs in the enclosure (leaving two hot spares), each affinity-bound to one of the two controllers. Since each controller has two ports, there are two paths to each LUN, and the OS is smart enough to load-balance across them. The two LUNs are striped with nothing fancier than Disk Utility. It's a totally standard configuration, and I've been seeing about 500 MB/s writes and 700 MB/s sequential reads.

RAID 5 performance is not an issue.

If you're dropping frames, you have some other problem. It's not your RAID level. But without some basic performance metrics from your framestore, it's impossible even to know where to start.

System is a MacPRo 2x3 GHz Dual-Core Intel Xeon/8GB RM running 10.6.2, FCP 6. Storage is an 8.0TB OWC Mercury Elite-AL Pro Qx2 eSATA. Drive is connected to a CalDigit FASTA-4e 4port PCI-e SATA card. About 2-5 minutes into the 30 minute sequence FCP will crash out giving me the dropped frame error messages. I also noticed that during playback I'll get a 2 second drop to black and the computer will be out of sync with the audio but my NTSC monitor will still be in sync. I noticed that when this happens the access light on the Qx2 system goes solid until it comes back to playing again.

rdedits Wrote:
-------------------------------------------------------
> System is a MacPRo 2x3 GHz Dual-Core Intel
> Xeon/8GB RM running 10.6.2, FCP 6. Storage is an
> 8.0TB OWC Mercury Elite-AL Pro Qx2 eSATA. Drive is
> connected to a CalDigit FASTA-4e 4port PCI-e SATA
> card. About 2-5 minutes into the 30 minute
> sequence FCP will crash out giving me the dropped
> frame error messages. I also noticed that during
> playback I'll get a 2 second drop to black and the
> computer will be out of sync with the audio but my
> NTSC monitor will still be in sync. I noticed that
> when this happens the access light on the Qx2
> system goes solid until it comes back to playing
> again.

Good info provided so far... thanks Gerard, Ben, and Jeff!

Rich, a few questions/comments:

- How many tracks are you editing? What are your sequence settings?

- This Qx2 setup has its "hardware RAID controller" in the enclosure and is connected to your Mac Pro via a non-RAID eSATA host controller. Performance is likely not as good as you'd get using a true HW RAID host controller (see next comment).

- Since the Qx2 uses one eSATA cable, you are limited to around 250 MB/sec. So, depending on the number of tracks and sequence settings, this may be an issue.

- Depending on whether you bought the case and drives separately, bundled, or the bundled "enterprise" version (enterprise rated drives) can affect the overall performance of your RAID. For example, if the bare drives used in the RAID are not enterprise-level drives suitable for RAID use, they can have too much latency, causing momentary (up to several dozens of seconds) pauses in disk I/O that can really mess things up (similar to what you've described). Also, if you put your own drives in the bare enclosure, you should make sure they are all the same size and exact model (and enterprise level / RAID qualified).

- What are you using for your scratch disks in FCP? Is your media on the RAID? Both scratch and media on the RAID setup?

If you can provide more info, it would help in figuring out exactly what's happening...


-Dave

Please add to the details the video output hardware and driver version you are using to connect the NTSC monitor.



For instant answers to more than one hundred common FCP questions, check out the LAFCPUG FAQ Wiki here : [www.lafcpug.org]

Also, download the AJA system test utility on this page and run a test.

[www.aja.com]

Also, how much space do you have on your drive?



www.strypesinpost.com

Thanks for trying to help me out on this guys, really appreciate it!

Very simple editing, maximum tracks are 5 or 6 and that's mostly text. Some of the segments are multi-cam sequences.

Sequence setting are NTSC 8-bit uncompressed.

Entire set-up was purchased as one unit from OWC.

Both scratch and media on the same drive.

I am using an AJA Io for analog in and output. I have downloaded the latest drivers from AJA.

Did run the speed test last week. Results were,
Write: 180MB/s
Read: 224.2MB/s

OWC wants me to put my drives into the new enclosure when it arrives and see if I still have issues. If I do they suggested switching to RAID 10 and copying over all my media to the new Qx2 set-up. I checked with OWC before purchasing to see if my CalDigit eSATA card was o.k. to use and they told me it would be fine. You know the last 30 minute show I did with this client I had all of my media on a G-Raid 500GB drive and all of their show elements were on a MyBook 2TB drive... no issues what so ever! Go figure.

Rich

rdedits Wrote:
-------------------------------------------------------
> Entire set-up was purchased as one unit from OWC.
>

Rich,

Thanks for the info...

Did you buy the $1100 version (3 yr warranty) or the "enterprise" $1800 version (5 yr warranty)? If you bought the former, then the drives inside may not be best for use in a RAID setup (latency may be an issue). They may also work just fine.

But, the activity light staying "on" for a few seconds seems to indicate something is "pausing" unexpectedly.

The enclosure could be flakey, one or more drives could be flakey, etc. Check your cable connection, and maybe even try one of the other ports on the eSATA card. The CalDigit card is among the best eSATA host controllers, if not the best.

You could also try to delete your FCP preferences (save favorites first), delete render files and re-render, make sure drives are over 80% full, etc. You could also try creating a new project and reloading your media and see how things work.

Besides using SoftRAID for formatting of one of my RAID setups, I recommend it for general use, as well, as its drivers are better performing than the Apple Disk Utility / Mac OS X version. Even better, the new version of SoftRAID, which will be out of beta later this month (v4) has several nice utilities for qualifying hard drives. If you thrash away (test) your drives for a few days before putting them into service, you likely discover any problems with the drives (if there are any issues)...

I'll stand aside now and let the true experts take over...


-Dave

Simply using AJA or Blackmagic Disk Speed Tests are not going to show where the issues are.

They simply show the average.

You really need Lloyd Chambers' DiglloydToolsTM Software Suite which will thoroughly check the RAID and give you a much better idea of the Data Rate over time and you will be able to see where the data rate drops well below a usable level.

I use it to check individual disks before making a RAID to check for any errors and performance issues. For those that use(d) it you might remember it was a Terminal CLI based app - I recently asked Lloyd to make a simple interface for it as it would make it far more accessible and I'm happy to say he's implemented a GUI version too!

Are you still getting the issue now you have the latest AJA IO Drivers?



For instant answers to more than one hundred common FCP questions, check out the LAFCPUG FAQ Wiki here : [www.lafcpug.org]

Yes still getting the same issues with the new AJA drivers. I should also add that on occassion the Qx2 would not show up on my desktop. It would take repeated power cycling before it would show back up on my desktop. On several occasions when I would open FCP, media files would be offline and I would need to reconnect. This never happened when I was using a simple G-Rad drive.

I should have the new replacement system by Thursday and than I can compare, still don't think I should set it up as a RAID 10 though.

Well firstly just transfer the HDDs to the new enclosure in order and test it as is.

If you are still getting issues then back up and test reformatting as RAID 5 or 10

If it is still flakey then you might need to check individual disks as I mentioned before, using the Digital Lloyd tools.

Let us know how you get on - I hate not getting to the bottom of technical issues!



For instant answers to more than one hundred common FCP questions, check out the LAFCPUG FAQ Wiki here : [www.lafcpug.org]

YEAH!!!!!! YES!!!! I just put my HDDs into the new enclosure and ran the 30 minute show off twice without any hiccups! Definitely the circuit board has the culprit. I'm almost tempted to transfer all the media over to the HDDs that came with this new enclosure.... worth it?

rdedits Wrote:
-------------------------------------------------------
> YEAH!!!!!! YES!!!! I just put my HDDs into the new
> enclosure and ran the 30 minute show off twice
> without any hiccups! Definitely the circuit board
> has the culprit. I'm almost tempted to transfer
> all the media over to the HDDs that came with this
> new enclosure.... worth it?

Well, you know that your current drives are working.

If you want to move everything to the new drives in the new enclosure, you should probably set that up and then run some extensive drive tests to make sure the drives are working properly (you should do this with any new disk drive).

SoftRAID, diglloydsTools (as Ben mentioned), and others can run your individual disks and RAID through some "stress testing" to qualify them before you put them into real production use.

Testing is always good, as most electronic devices exhibit a "horseshoe" (I think that's the term) reliability curve, i.e., failure will occur within a short time, then a long period without failure, followed by failure some year(s) later...

At least you sorted out the issue, it seems...



-Dave

Thanks Dave.I think I'm going to just send the new drives back. I'm not really gaining anything by transferring media over to them, other than a couple more hours to my day. They have been working nicely all day now so way screw with it. I'm one freakin' happy camper... at the moment.

Rich

Rich,

I hear ya...

You've already spent a bunch (too much) of time on this issue...

Next time you upgrade your RAID, or get new drives, you may want to use one of those tools to test things before you need to use them for real work. Dealing with a bad enclosure or drive is much nicer when you're not trying to get real work done.



-Dave

Great advice and I will!!!!

Rich

rdedits Wrote:
-------------------------------------------------------
> YEAH!!!!!! YES!!!! I just put my HDDs into the new
> enclosure and ran the 30 minute show off twice
> without any hiccups! Definitely the circuit board
> has the culprit. I'm almost tempted to transfer
> all the media over to the HDDs that came with this
> new enclosure.... worth it?


Sorry to bring up an old post, but I'm having the same issue rdedits had.

rdedits, how did you get OWC to send a replacement? Did they say exactly what the problem was?

We have two of these Qx2 drives (12TB each) and like you were saying, if we play back a video (DVCPRO HD 1080p24 and/or ProResHQp24, 30 mins run time) it will hiccup/stall/drop frames after about 3-5 minutes. It doesn't matter whether it's being played back straight from Quicktime, FCP, or AVID via FW800 or eSata. One enclosure is setup as RAID0 and the other is RAID10. We've also tried hooking both enclosures up to different machines - same result, dropped frames. We can take the same files and play them back without any issues off our CalDigit HDOne. They even playback fine off a LaCie Rugged (5400rpm). Any advice would be helpful. Thanks!

Drag man... If I made a uncompressed QT file of the sequence it would play back o.k. but that was unacceptable to me since I was able to edit without any issues off of older eSATA RAID systems. They eventually swapped it out with a Sans Digital miniSAS RAID enclosure. Not sure what the problems were with the Qx2 systems but I could play the same 30 minute shows off of a CalDigit VR mini connected with eSATA with zero issues. OWC was extremely helpful in trying to find a resolution but of course my situation was within their exchange period.

Last winter I had issues using the Qx2 at a client facility. The unit would drop frames in both playback and record. Using the AJA tool, and looking at the graph it was obvious that the unit had very spiky performance, and while the average data rate was good, it would drop to a much lower rate quite frequently.

OWC was great in their support working through the problems with us. At first, as reported in this thread, they tried to suggest that RAID 5 was not a good solution for video editing. As it turns out, the were sort of correct. On THAT unit RAID 5 is not sustainable. There is something in the chipset of of the onboard RAID controller that seems to take a break every now and then. Maybe runs out for smoke?

In any case we wound up creating a solution with the two products below at a similar price point, which worked well for us, and to my knowledge continues to work for them:

[eshop.macsales.com]

[eshop.macsales.com]

Others here have since commented unfavorably on the Rocket Raid line, tho it it seems to working well for my client.

Thanks for the feedback. I'm hoping they give me the option to replace the enclosures since I've been going back and forth with them for over a month while they try to find out why their drives aren't working. If that's the case, I'd go with two of these (http://eshop.macsales.com/shop/firewire/1394/USB/EliteAL/PerformanceRAID) and one of these (http://eshop.macsales.com/item/Other%20World%20Computing/RPMSS4B12.0T/). Up to now their customer service has been helpful. I'll keep you posted.