> I did see significantly higher burst rates.
> I bet smaller files would finish much, much faster on the 790 v. the 3132.
> But you said you would be coppying large files, not small ones.
Hmmmm... The controller and PM should not know or care about file size.
The OS, filesystem, layout of data on the disk (amount of seeking required)
may be affected by file size.
> leans towards the 2 drive raid 0 VRaptor's being the limitting factor
One way to take the disk's performance mostly out of the equation is
to read small amounts of data from the disk's RAM buffer. This
eliminates platter rpm and bit density, leaving only the disk's
electronics, and the controller/PM as bottlenecks. I'll attach a
small C program that does this. Tested only on FreeBSD and NetBSD.
(If you don't want to mess with it that's ok. I get the impression
that you enjoy testing this stuff so I thought you might be interested.)
Every time they increase the density of bits on the platters,
the sustained performance goes up, even at the same rpm. (Doesn't
help the seek time, though.) The current 2 TB drives are over
twice as fast as the 250 GB drives of a few years ago.
> No matter what the scenario, or what the 3726 is plugged into, you
> can expect the max you will see for EXT->INT is around 120MB/s
This might be, although it seems a bit odd that the 3726 would have
exactly the same total limit as the 3132 single port limit. Also,
Petr Vandrovec got 133.95 MB/s from the 3726.
> What is Pass-Through (Actually spelt, "Pass-Thru" in the software raid
> program)? I have no idea. All I know is it allows the OS to see the drives
Sounds like Pass-Thru means pure port multiplier with no raid of any kind.
Which is the mode I want to use. But if it hangs in BIOS I can't use it.
> BUT, if you use the software raid program to assign a raid mode, the 3132
> will not hang during boot. If you want the OS to use the drives independently,
> you have to assign each drive to a *Consintricute* (SP?) raid mode. This
> setup will not carry over to the 790. The 790 will detect un-partitioned
> drives, and vice versa.
The software raid program must be storing the configuration as
"there is a raid attached to the 3132 port 0" rather than having some
sort of label stored on the disks that make up the raid.