In the last parts of this article we’ve covered the important considerations around audio data delivery systems including RAID use and types. In this article I’m going to give you my direct advice as to how to move forward, and how to insure you’ve formatted your drives appropriately for audio.
“I Set Up My RAIDs With My Controller And Everything’s Good.”
Size does matter. Well, stripe size anyway. One of the most important benefits about using a software RAID controller is the capability to user select a RAIDs stripe size. Hardware controllers generally default to certain sizes based on the operating system, but many times this is a problem for AV use.
For simplicity’s sake, the “stripe size” allows the RAID controller to “pick up” a particular size of data as the head spins by a desired point of data. The smaller the stripe size, the more activity is required to read large files, but it also allows for more efficient use of the drive space. Larger stripe size allows for uber fast large file transfers, but it suffers strong read penalties when many smaller files are used. It also tends to cause inefficient use of drive space. For compressed video file use, I’d suggest 128KB. For uncompressed video sizes of 256KB are okay. For
audio, however, these sizes will not do. For sample libraries you should not go higher than 32KB, and for general audio 64KB is the setting I’d suggest. RAID 5 and other parity using RAIDs have been reported to have an opposite effect:
Mark! Tell Me What To DO!
Okay. I will. Because there is really no easy solution for audio AND video outside of an external Solid State Drive (which I use for samples), here’s a breakdown of how I would do things if I were you.
• All drives should be 7200 RPM or faster.
• Create a separate RAID for anything to do with audio mixing. Your video rendering and payback should be striped and formatted in a way which is efficient for video – and that is almost never the same for audio.
• Use a RAID 5 for your audio. Tweet: RAID 0 is unnecessary for audio and introduces too much risk.
• Make your disk stripe size 64KB.
• I’ve seen a slight degradation of bandwidth between USB 3 and eSATA, but not much. To find out how fast your drives are you can use whatever system resource you have (Activity Monitor on a Mac) and the BlackMagic Disk Speed Test. It’s a great little free program that gives you an average of what your drive/RAID is capable of and gives you a breakdown in video formats of what you’ll be able to read and write.
• When you do the format of your RAID, and you have the time, do what’s called a “low level format.” This has the computer write and read every useable space on the hard drive. If it finds a bad space, it marks it on the drive, and the system will never use that space again.
• Tweet: If possible, use only 40-50% of the drive itself. The fastest portions of the drive are on the outside of the platters. Those are the bits which are used first. As the drive fills, you’ll find files will receive up to a 15% write penalty…especially if you have to read and write from older files to newer files. The heads have to slide from one side of the platters to the other. In drive-time, that’s an eternity. It’s possible to format you drives only 50% with software RAID controllers.
• Have a killer backup protocol (Covered in the next part of this article).
Now, I know some of you are going to ask, “well, what’s your system like, Mark?” and, indeed, you should do as I say not as I do. But I break my own rules because of such a large amount of files being used at my facility on multiple projects – by multiple people. For me, it’s better to have drives and systems which deliver an assortment of benefits depending on the scenario and I educate my staff about them. With the exception of RAID 4, 1+0 & 1, I use everything. But I also am OCD about backing everything up exactly as I’ve suggested here.
There’s so much more to learn about RAIDs and drive storage protocols for audio, but you don’t need to know much in order to have a killer system which will serve you well for a long time…and won’t mess up your video system.
In the next and last part, we’ll cover the critical issue of backing up your data and insuring your RAID data is well protected. Let us know your experiences around storage issues or Tweet about it!