Hendrik,
<snip>
I'm going to want to try to come up with some settings that allow capturing uncompressed video (18 MB/sec) while one or two other users are trying to read DV video (3.5 MB/sec) from the same drives. I guess that means I will want get the cache written to disk as soon as possible (leaving margin for difficult moments) while allowing other users to read from the disk on demand. In some ways, reading video files is more demanding than writing -- because what is read MUST arrive at the client computer exactly when needed.
Could be problematic since you can't just add bandwidth requierements and compare it to the maximum bandwidth. Multiple active disk access jobs means that the disk will be seeking, which means that the read accesses will interfere with your write stream, possible to a point where the writing will skip.
If you are not writing 24/7 and it's in your budget, I would put two RAID arrays into the machine, one to write to and the other one for reading. You can synchronize them whenever you are not writing. Of course, that only works if you don't need to read the written data immediatly. For the read array I would use Raid5 for the data security and for the write array you can either use Raid5 or Raid0. Raid0 is faster compared to Raid5, especially for writes, but it would mean your data isn't secure until it has been copied to the other Raid5 array.
Dirk
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