I have several dells with the perc controller
and I can say that the best solution is
to user raid 0 (see both disks) and let
zfs to mirror them..
This works ok, and you can use the zfs tools to
manage the disks.
Howerver this does not solve the problem that I
had with the perc controller..
The problem is that all the storage you have is
in the perc controller, even it is reliable, when
it "breaks", all of your storage (and so the computer...)
is useless. You cannot move the drives (HD) to another
machine because the "normal" controller (ad, ada) will
not recognize the disk.
Even if you have a spare perc controller of the same kind
at hand (and I bet you do not have...) the disks are
"signed" by the other (the broken) controller and so
will not be recognized by the new controller.
In my case I had to call dell support, and only after
several hours I could put the HD online again.
I mount only one disk (of the zfs pool) in the new
controller, and even with the dell support in the phone
the new controller wipe out the disk.
A new call (with a different dell support) was able to
re-initialize the disk, that includes re-install Freebsd...
and after that "attach" the old disk, and using zpool detatch,
followed by zpool attach (the old disk), it than reconstruct
the mirror... resulting in almost 6 hour downtime
and a loss of one day working for the hole company.
Now, a dell support (here) does not attend you if you say
that the OS is FreeBSD, you must say to them that you are
installing Linux... to get the support.
Conclusion: now I prefer the IBM 32XX series...
that is my story
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