Areca vs. ZFS performance testing.

[Danny Carroll]

Eirik Øverby wrote:
> I have noticed that my 3ware controllers, after updating firmware
> recently, have removed the JBOD option entirely, classifying it as
> something you wouldn't want to do with that kind of hardware anyway. I
> believed then, and even more so now, they are correct.

It kinda depends.  If there were a good 8 or 16+ port SATA card out
there that *simply* did SATA with no bells and whistles, then there
would be no point buying a Raid adaptor when you want to use things like
ZFS.

But there are no such cards available.

> Use the RAID-0 disk trick to be able to utilize the controller cache.
> And regarding write-back vs write-through; I believe write-through is
> equvivalent to disabling controller write cache, however it WILL cache
> the writes in order to respond to future reads of the data being
> written. I would guess, but I don't know, that this also goes for
> disk-level caches too, though, so it probably doesn't matter.

It is interesting to me that the default setting on the Areca card was
to have the disk caches turned on.  I think that is strange because by
default you have a situation that can lead to data loss even if you have
a battery backup unit.

-D