[Fedora] Re: RAID suggestions...

[Ashley M. Kirchner]

Bill Davidsen wrote:
> fast - reliable - inexpensive. pick two.
    In order of importance, I would put "expensive" as last, with fast 
and reliable being the top ones.  This doesn't mean it has to be an arm 
and a testicle expensive, but at the same time I'm okay with spending a 
couple of thousands building it up (over time).

> But unless you are running multiple video feeds into the disk at one 
> time, fast isn't an issue.
    I guess it depends on how you look at it.  I can be encoding one 
feed, and watching another at the same time, or encoding and importing a 
second feed (from camera).  And while I realize that the encoding part 
is primarily CPU intensive, the disk does get taxed at the same time as 
it's writing frames out.  And if I'm importing another feed at the same 
time, the drive will pull double duty.  So if I'm going to be using the 
same cluster of drives for this, it would have to be able to keep up 
with that.

    The other option is to build two separate, smaller RAID 
configurations and use one for importing feeds and the other to encode 
on.  With a quad core CPU, it'll come down to other bottlenecks in the 
whole architecture, be it bus speed, network traffic, or simply how fast 
the camera's feeding data in.

> Commodity SATA drives will do 50MB/s without effort, and 200MB/s is 
> readily reached using software RAID. If you want fast and reliable, go 
> SCSI.
    While I don't have anything against SCSI drives, except for the high 
cost, is there any particular reason why you prefer SCSI over SATA II?

> For SCSI I have had good luck with the "ServeRAID" IBM controllers. 
> They're Adaptek with IBM firmware hacks, I believe.
    Adaptec is already on my list of vendors. :)  Thanks for the 
confirmation.

    - A