RAID 0 is slower with small files (audio samples)?

[neptunefix]

Is it true that a RAID 0 array is faster for larger files, but can be slower for reading small files? Do you guys see a huge jump in performance when you go to RAID 0? Just wondering if it's going to give me a nice boost for an audio production work drive (non OS).

 

[joshg]

Hmmm... All that I've heard is that RAID 0 gives no noticeable performance gain on smaller files, but sometimes a very significant performance gain on large files.

To me this means that if you will only be accessing small files from your disk, then the cost of RAID 0 is not worth the performance gain (which will be very small and pretty much not noticeable). However, if instead you are working with larger files a lot then you would benefit significantly from the performance gain of RAID 0.

From what I understand and from interpreting those statements above as I have, it means that RAID 0 will have the following effect:

Small files - Since the time required to gather this data is just about equal to the time required to access the file, you still are just waiting for the disk seek time here. Therefore, performance should be exactly the same (depending on exactly how small the file is and your stripe size) as if you were just using 1 hard drive.

Large files - Seek time remains the same as single drive, however, the larger the file, the greater the performance boost (vs. a single disk setup). This is due to the file being accessed simulataneously from 2 disks.

That's my take of it, at least. I have no real experience with RAID 0 at this time, however hopefully I will be setting one up on my PC within the next month or so

 

[jaaron]

raid 0 will give you a boost with smaller files although (as the previous post said) larger files is where it's really noticed...

5x raptor
single drive (boot), 2x raid 0 (projects), 2x raid 1 (backup = I hate tape)... It's pretty nice...

 

[tallman45]

I have done extensive testing with 2 and 4 drive Raid 0 arrays. Smaller file (OS/apps) read and writes are slower with a Raid 0 that with a single 8mb cache drive. Read and writes of large files such as digital images is substantially faster with Raid 0. The reason is that the data must run through the controllers striping process, the data needs to be split between the number of drives in the array. Many small files may not be split at all meaning that the data went through an extra step.

For small file read/writes (including OS/apps) I have found that single drives on independant channels provide much better performance gains over a Raid 0, plus the reliability is substantially better as well. A Raptor/SCSI would offer the best performance for small file requirements. The access times are the key.

Partitioning a drive and put your most accessed files towards the outer edge to gain the most performance out of any drive.

 

[neptunefix]

I need a "work" drive for audio, sampling, AND video editing so the speed I get for video will be worth it. I was just worried my audio sampling and some apps would slow down. I'd like to keep the number of hard drives I use down to 3 drives (os/apps + RAID 0 for projects) to avoid the heat and noise of adding a 4th.

Thanks for the input, guys.

 

[tallman45]

You can configure Raid controllers for Raid or just IDE channels. Since you will be dedicating the Raid for scratch/work files you can easily do your own benchmark testing with either 2 single drives on their own channel or a 2 drive raid. For smaller file work you will want to experiment with the stripe sizes of the array, some onboard controllers anly allow one stripe size and this may be larger than the files that you are working with. Tuning will be key to get the best performance based on your processing needs.

 

[boyRacer]

it depends on the stripe size of the array.

 

[nickaskew]

Hi,

You say you are worried about the 'small' audio samples you will be working with.. are you classing 64kb as small? - if you have a RAID 0 array, the first step to configuring it is specifying the block size it will work with - IDE RAID for example generally has 64kb as the MAXIMUM block size you could work with.. so 128kb is classed as a large file (2x64kb across 2 drives)

You also mentioned that you like the benefit it would bring to streaming video... that statement sums up what you need, it won't be any slower than a normal drive for your smaller files unless your smaller files (we are talking hundreds of them, being used at the same time..) are around 4kb each - if your files ARE that small, they would be popped in the drives's cache anyway so you wouldn't have to wait for the controller to stripe it across your disks.. you may have more of a performance hit on slow files (and again, only if you were using loads of the little buggers) being read from the disk - because those files would not be stored in the cache.

I have been using IDE RAID for a couple of years now at home (having used SCSI in business for many more..) and can honestly say the speed is tremendous (not uncommon to keep a sustained write of 40MB/sec), I even use them for small file servers these days.

Regards

Nick