- Posts: 203
- Joined: Wed Aug 22, 2012 2:30 pm
- Location: Toronto, Canada
Write speed on RAID 5 is always slower than it's read due to the Parity calculation. For single long files this tends to be less invasive, but with several files (read:sequenced images) this will be worse because parity is calculated for EACH file.
So, to make some calculations here. A three drive RAID 5 will have a throughput of around 120 MB write and 150 read....SATA3 Drives and Controller may make that faster, but I'm assuming SATA2 in this case.
So these are also kinda optimal numbers. Format will be an important factor here. For example 1080i59.94 10Bit YUV uncompressed needs 156MB/second. Which is over your realistically consistant throughput. If you're doing our DPX it's RGB it's a bit bigger (due to being 4:4:4 and not 4:2:2). As the resolution goes down so does the requirement, so you might be using some other format like 720p or 486i.
So I guess the first thing I'd do is find out the data rate of your sequence and then run the disk speed test on your RAID (keeping in mind what I said above about a single file requires less overhead than a sequence).