[Tig] Minimum RAID bandwidth for 2K playback?

[Ramona Howard]

> Note that these "enterprise" SATA drives are slower than higher grade
> (much more expensive) 15K SAS drives.  The seek time is about 9ms and
> the transfer rate is just over 100MB/s.  Compare that with seek times
> of 2ms and a sustained transfer rate of 171MB/s.

 * Remember faster drives generate more heat so that plays into an overall 
system design. 
 * Real world you may not get either of these numbers from the drives so don't 
always count on those numbers. Testing with your application, OS and 
additional hardware will be the only real numbers you can trust.  There may 
be a bottleneck in any of these preventing you from getting close to the 
theoretical numbers the drives can give. Unless you know how to get around 
them your stuck.
 * Seek time certainly helps but is not the only factor. We have tested and 
can use both of the drives mentioned above.  If you have a window of time on 
which you MUST get the data from the drive/s, then drives that fall within 
that window will work. Seek time will help with various other issues, such as 
fragmentation. But again this can also depend on the application/system 
design. (A poorly designed app/system and it won't matter what the seek times 
are).
>
> If you get a controller which supports both SATA and SAS (SAS
> controllers normally also support SATA) then you preserve the option
> to install SAS drives.

This is the best thing you can do to not back yourself into a corner.


Cheers,
Ramona


-- 
Ramona Howard
CEO/Founder
SpectSoft, Inc.
375 Johnson Ave
Oakdale, CA 95361

Phone: 209.847.7812 extension 104
Fax: 209.847.7859
http://www.spectsoft.com