Re: 2 Promise E-Class enougth for 6 HD Streams?

You have to take into account what your facility will need as top end. Is your top end 4 bays of uncompressed HD and one doing 2k dpx files? If this is the case you will drop frames for sure. You have to factor in the possibility that those 4 bays may need access to more than one stream at a time. I usually factor 3 streams per bay on any compression, just in case. (minus 2k and above, since the machine won't handle more than one stream)

With that in mind, you are looking at 4x3x160=1920 and one bay running 2k adds another 300MB/s max.

Now, do you really need to put together a SAN capable of putting out 2GB/s? I can't answer that, but that is a possible reality. When I have tested this, 2 raid heads in active/active mode will not give you more than 500MB/s writes and 900MB/s reads, approximately.

4x160=640MB/s Two boxes will absolutely handle that, one box... doubt it. If you add a stream of 2k on to that... good luck, you'll be at your roof.

You might live completely in prores on your main bays with the occasional 2k in the grading bay. In this scenario two boxes will be fine. I like to take into account room to grow and head room... just in case.


1400MB/s is a number all RAID manufactures put out because it comes from IOmeter testing. This is a very nice easy test that shows total output of the unit under nice 1MB file transfers. This absolutely does not relate to number of video streams. Also to be clear, any published numbers of video streams have to take into account XSAN, so be sure to look for XSAN qualifications, not direct attached since they will not relate to your circumstance.


-jw