Capture Problems with ProRez 422 HQ

[Jeremy Garchow]

You have an 8 bay raid hardware raid3 and you are getting 60 MB/sec? Sounds like you have bigger issues.

Jeremy

[Gary Morris mcbeath]

Not sure what you mean. I know it’s not like the newer units; It’s an older Jems unit with ATA drives, had it since 2002, that’s as fast as it’s ever been. Driven by an ATTO UL4D SCSI card, latest drivers. About the same speed as a G-Raid with two SATA drives.

But that should be fast enough for one, maybe two streams of ProRez HQ right? Around 27-30MB/s max?

I’ve read every manual, tried everything I can think of for two days.

Thanks,

Gary

[David Roth weiss]

q[piper] “scratch disk is an 8 bay hardware raid 3, tests 54-57 MB/s write, read 68-72”

Gary,

First, your throughput is awfully low for an 8-drive raid array. You’re getting only slightly higher read/write than what I get on a single drive. My 4-drive SATA array averages 191.0 for both read and write. Something seems wrong with your numbers or with your raid subsystem.

More importantly, these read/write speeds are too low for capturing HDCAM and are more than likely not capable of maintaining the throughput necessary for conversion to ProRes422 during capture.

David

David Roth Weiss
Director/Editor/Post-production Supervisor
David Weiss Productions, Inc.
Los Angeles

[Gary Morris mcbeath]

I was afraid of that. When I look at the graph on the AJA system test, there are little short duration spikes that go way down. I’ve been looking at the average write speed.

As I indicated, this is an older unit, albiet with new drives and new UL4D SCSI card, worked great for SD and works great for AJA DVCProHD; I had hoped it would be good for at least one stream of ProRez. Guess not.

Just an additional note: my year & a half old G-Raid FW800 320GB raid0 tests at the same speed as the larger unit with AJA’s system test.

So, what might the reason for the double speed/half duration video play back, while the audio goes the full duration of the clip? Remember, I tested the clips in QT and it plays at normal speed and duration, just with the occasional jumpiness from the dropped frames.

Boy, you folks are as bad as me, working all night. I guess we love our work.

Thanks for all your interest.

Gary

[Bob Zelin]

Hi Piper –
as everyone else has already stated, your issue is with your drive array. Right now, if you use AJA Kona System test on your internal boot drive on your MAC, you will get about 60mb/sec. I don’t know the older SCSI to ATA JEMS unit, but older 8 bay SCSI arrays (8 Seagate SCSI drives with an even older ATTO UL3D) were over 200mb/sec, and were the original type of arrays that were recommended for uncompressed HD. So old does not mean that it does not work.

It always frustrates me when one drive in a JBOD that is dying boggs the system down, instead of simply just not working. This is how you need to find this issue (and I know this will be painful). You need to DELETE the RAID, and test EACH DRIVE ONE AT A TIME with AJA Kona System test. You will find that only one drive is much slower than the rest. For a quick fix, you will find that simply disconnecting this one drive, will allow your RAID to run at correct speeds for what you are doing (220mb/sec with ProRez 422HQ). Once you find the slow drive, just stripe the remaining 7 RAID 0, and away you go. You will be back in business.

Bob Zelin

[Gary Morris mcbeath]

Bob,

That makes sense; I’ll give it a try. Since it is a hardware controlled raid, not striped by software in the computer, the computer sees it as one drive. But I think I can test each drive by removing the others (they are on sleds), or test them two at at time and by a process of elimination find the offender.

I have a sense, though, that it may be time for a new one. This unit wasn’t very fast from day one; oringinally had 125 GB drives, then I replaced them with 250’s with 8mb cache. Same speed. And these new drives only have a 150 hrs or so on them. It has dual power supplies, dual fans, and dual controllers. I once tried restriping it as RAID 0, only got a 12% increase in speed. The company that made it started out as Infotrend, later became Jems, then was bought out by RAID Inc. They no longer support this unit.

Thanks Bob, I appreciate the info. I’ll get back on this.

Gary
SaltAire Cinema Productions

[Bob Zelin]

WOW, I know this drive array – Infortrend is STILL IN BUSINESS, and you can send it directly to them for support.

Your unit will attempt to create a RAID, when you turn it back on, so at 2 drives at a time, this will be a VERY time consuming process.

bob Zelin

Infortrend Corporation
2200 Zanker Road, Unit D,
San Jose, CA. 95131, USA
Tel: +1-408-988-5088

[Gary Morris mcbeath]

Hi Bob,

Yes, I just went through the raid, pulling one of the drives at a time, trying groups of 2 and 4 drives at a time, as well as all 8 drives, all configured as RAID 0; Ran the AJA system test in each configuration.

Results: all showed an average of around 82 MB/s write/75-80 read; about a 12% increase from the RAID 3 config. Didn’t matter if it was two disks or 8: same nominal results.

With the slight increase from the RAID 0, I again captured a couple HDCAM clips: still dropped frames, and plays back the video portion at 2x speed, while the audio plays normally for the clip duration.

I’ll contact Infotrend on Tuesday, but their website says support for resellers only, no end user support. But I’ll try anyway.

I heard somewhere that the Kona2 does not do any hardware acceleration for ProRez like it does for DVCProHD. I’m thinking that might be a factor here as well.

Thanks to all of you for your help.

Gary
SaltAire Cinema Productions

[Bob Zelin]

82mb/sec won’t help you – 2 internal SATA drives in your G5 will do 128mb/sec, which is certainly enough for uncompressed 10 bit SDI and DVCProHD. I can’t answer on this about Pro Res 422 HQ. Many products, including the Cal Digit, and many others, will EASILY handle
ProRes 422 HQ, as well as DNxHD for AVID , and so much more. If you don’t want to spend any money, I urge you to directly contact Infortrend.

Bob Zelin

[Gary Morris mcbeath]

I’ll give them a call Tuesday; But I’ll probably spend the $ for a new raid, however. Then the older unit will be a nice, big, parity protected backup drive.

Thanks again for all your help.

Gary