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What’s a good RAID setup?
I want to speed things up. Don’t know much about RAID. Currently have one drive for system, one for video files, etc. Is it smart to RAID the system disks? Or just the Data disks. Or Both?
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15 Replies
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First things first. What type of speed-up are you expecting? If you RAID your disks you will probably see a little bit of speed-up, but depending on what you do, it will probably be somewhere between marginal and not noticeable. Rendering times will probably not be affected by RAID at all.
As you probably knows, RAID comes in a few variations. Some increase speed, some increase reliability and some do both. To do both you need a minimum of three (preferrably identical) harddrives. Three, for example, 250G harddrives will give you a 500G of reliable, and slightly faster RAID.
Since you posted on a video forum I assume you are doing this on a video editing system. There isn’t many parts of a video editing system that is slowed down by your harddrives though, which leads me to think that you may get disappointed by going to RAID, since you will most likely not notice any real speed-up.
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Terje A. Bergesen -
Thanks, Terje. Yeah, I’m doing video. If the speed-up will be minimal, and I back up regularly…then no need I guess. What kind of work benefits from the speed-up of RAID-0?
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If your application currently needs data faster than the drives can deliver then a striped array may help. This will come into play when using SD uncompressed, possibly SD 4:2:2 or many HD formats. Not HDV, though. HDV only requires as much throughput as DV25. Cineform intermediaries require more though.
Most low end RAID puts a little extra load on the CPU – which will actually slow your renders a smidge! Another option is to use 10k RPM Raptor drives. I saw a recent test illustrating that these can actually rival a 2 disc striped array.
Watch your task manager. If you have reduced playback framerates but your CPU isn’t being taxed then maybe you have a disk throughput problem. If the CPU is running full out then a faster CPU is going to be much more effective than faster discs.
Rob Mack
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What kind of work benefits from RAID-0… It really depends. On a lot. The problem with ATA (even the SATA version) is that it engages the CPU when it writes to disk. Some times it takes quite a bit of CPU in fact. In such cases, almost no applications at all will benefit from RAID. Only an application with a huge amount of disk access and very little CPU access. Some Database stuff perhaps. For this reason, I’d recommend RAID for safety, but not for performance.
If you RAID better disk technologies, such as SCSI, where most of the intelligence is on the SCSI board and on the drive it self, you will see significant benefit from RAID in disk-bound applications such as heavy database work. This is the fact of SCSI most lost on people. SCSI in and of it self may not be much better or faster than ATA/SATA, but since there is more intelligence in the board/disk combo, it doesn’t tax your CPU each time you access the disk. This can, in multitasking and mulitiuser environments, translate into significant performance gains.
For video work, unless you are working with uncompressed or only lightly compressed high-resolution footage (is not such), your disk concerns are more in size than in speed.
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Terje A. Bergesen -
I’m editing AVI files, from mini-DV. Any FX at all lower the frame rate considerably, which I understand, is normal. But the CPU is only working at 50% during those times. Hmmm. During renders the CPU is doing 100%, which is great. Now, I have a slight drop in the rate also with no FX (in Good – Full)) but this is small, say 29.0 fps. Still, with a 3gig HT chip and 1 gig memory you’d think it would be perfect.
So this thread started with RAID questions. Me wondering if my drives were a bottle-neck. If the CPU is only at 50% but the frame rate is low, you’d think it was the drives. But because there’s only a playback issue when FX are going, and assuming that the CPU is in charge of processing those effects, you’d think it was the CPU’s fault. And I wonder why the CPU isn’t working full-time to give me better playback. Maybe this is just the way Vegas talks to the CPU? -
Any FX at all lower the frame rate considerably, which I understand, is normal. But the CPU is only working at 50% during those times. Hmmm. During renders the CPU is doing 100%
I am not quite sure I understand the above. When is it that the CPU is only at 50%? Is it during preview? You say it is at 100% at rendering.
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Terje A. Bergesen -
Could this be an issue with HT? Perhaps you should try turning it off in BIOS and then trying it again?
I don’t actually know if this is an issue but suspect it might be.
Rob mack
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In fact, the first time in my memory that we did render tests, spot turned in the best time with a system using SCSI discs. A very similar system with ATA discs was a little slower.
SCSI is costly but you can now get external arrays that are scsi on the outside and SATA on the inside. They’re a bit cheaper.
Rob Mack
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In response to the original question:
*DON’T* RAID your system disk! The increased risk of drive failure isn’t worth the speed increase.
Some of what the others have said has merit, but I do see a marked data throughput advantage to a three-drive or more SATA RAID 0 array. It’s even higher if you buy a dedicated RAID controller board, rather than relying on the motherboard’s built-in RAID, or a Windows software-based RAID.
Make sure your power supply has the juice to handle all those drives.
Regards,
Doug Graham -
Terje – yes, during preview the cpu is at 50% but the frame rate is quite low. During renders the cpu is at 100%. So it’s confusing. My guess is that with multiple FX on during preview, the CPU is unable to work at its full potential because of the way the FX plugins are giving the cpu instructions on what to do.
I was told the video card doesn’t have to be anything too special to get good preview-playback.
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