Is RAID absolutely necessary for video editing?

[gluchy]

Hello,

I am planning to build a new computer for home video editing (just some vacation video's nothing else ). I have been reading about hardware requirements, including HD. Some of the sites suggest RAID 0 (for performance gains), but I would like to know if the RAID is really needed? Would just a nice HD from WD with 16 MB cache be enough to provide good tranfser rates?

Thanks,

Peter.

 

[sithscout80]

If you are doing normal DV (720x480), you don't need RAID at all. If you are doing High Definition, I believe RAID is a must because hard drives cannot support the I/O needed for transfer. I would recommend 2 or 3 hard drives for normal editing. I do lots of video editing with Adobe Premiere Pro and I havee 1 HD with Windows on it, another with the captured video and another for all the temporary files that it creates. This greatly improves performance.

 

[sailer]

Simply put, RAID isn't needed for anything at all. I am assuming that you're thinking of RAID O. It does speed up transfer rates, etc, but if you don't need the fastest setup around, then it isn't a great advantage. RAID got its start years ago when hard disc drives had a lot slower transfer times than they do now and a lot smaller caches, etc.

The ugly part of RAID is that if one disc fails, then the whole system fails. That doesn't happen very often, but it does happen. For a commercial use, with everything backed up constantly on other drives, RAID is well worth it. For home use, I don't think so. For the useage that you appear to want, a 150 mb Raptor would probably work fine. The Raptor is fast, efficient and doesn't require the complexity of two slower drives in a RAID configuration. Of course, if you want to put two Raptors into a RAID, then your speed will go up even more, but that's even more money spent.

 

[JohnWeldt]

RAID will make a huge impact in terms of large file editing and transcoding but not required. But you need the CPU power to back it up too.

For example a opteron 275 with RAID0 is about the same as with out. A dual 275 with RAID0 total out put is very good. With out RAID0 it is about average to a 275.

 

[sithscout80]

If you edit HD, RAID is necessary. At 10 bit color depth and full HD resolution (1920x1080p), the required I/O bandwidth is 311MB/s on average.
This data is taken from page 7 of this article from Adobe.

 

[JohnWeldt]

the required I/O bandwidth is 311MB/s on average.

How do you get 311MB/s out of a RAID setup? Are you talking sustained speeds of 311MB/s?

 

[sithscout80]

For transfer of that size HD file uncompressed, you need a sustained transfer rate of 311MB/s. You can either do this with a very large disk array in a RAID setup. To achieve those rates you would need a lot of disks.
Mostly how people avoid that hassle is to compress HD before they transfer it to the computer. Makes it easier to edit and to store.

 

[pkquat]

I asked a similar question a while back and did some testing as well. With standard 720 x 480 video, I would recommend two hard drives in a non RAID 0 setup. Have the source video on one drive and the destination on the other drive. This way you will get comparable performance as RAID 0 because most of the time one drive is reading from a localized location and the other is writing to a localized location. With a RAID 0 set up both drives would be reading and writing to difference locations on the drive.

I have a partition on my OS etc. drive for my desitnation files. This way the end video is usually writing to an mostly defragmented drive. All my source files are on the other drive. This drive is also mostly defragmented.

 

[gluchy]

Wow, what a wealth of information. Thank you guys!

Well, that answers my question. No RAID for me at this time, as I will not be doing any HD. I will very likely go with 3 drive setup similiar to what sithscout80 and pkquat suggest. (1 for OS, 1 for the source files, 1 for destination files).

Having said that does a cache size make that much of a difference? (8 MB vs 16 MB)?

 

[JohnWeldt]

Having said that does a cache size make that much of a difference? (8 MB vs 16 MB)?

For many small files they do. I have not seen much gain on large files.

 

[sailer]

I think you missed a line I wrote, that "for commercial use,..., RAID is well worth it" Its for home use that I think that non-RAID systems are just as good, when time is not an absolute necessity. And as JohnWeldt pointed out, you need a lot of cpu power to back it up. From what was written in the original question, it seemed to me that the computer being built was not going to be the latest, greatest, fastest, but more like an average home computer. My guess is that for what he is building, a non-RAID setup would do him fine. I could be wrong, but its my guess.

 

[sithscout80]

Yeah, I missed that commercial part of it. For a home environment I'd recommend a daily backup system because there is a greater risk of accidentally deleting something that is required or a virus, in which RAID doesn't help, than a drive dying when a deadline needs to be met, in which RAID is very helpful.