Beginners questions

Cassandra von Ahrcanburg proudmouse at
Fri Dec 6 08:13:40 PST 2013

On Sun, 1 Dec 2013 12:47:46 -0500
Justin Sherrill <justin at> wrote:

> I'd argue it may be a symptom of pseudo-hardware RAID, of which
> there's a lot - hardware devices that don't present a unified volume
> image to the operating system, and depend on a software driver to
> accomplish what they do.

I don't know what hardware exactly was used. What I do know is that
they were using NL-SAS drives and an SAS RAID controller.

I don't like RAID controllers because nothing is compatible to anything
else. Often even to different controllers from the same vendor cannot
read each other's drives. If the RAID controller breaks down (and that
happens more often than you'd think), you'd better have a space or hope
that someone is selling one on eBay.

> Well, you can hammer-add all day long - but this is not a RAID; you
> lose a disk, that data is gone unless you have it streaming to
> another Hammer volume.  People have used vinum on DragonFly for
> software RAID, which may work as an option.
> You'll have to do some contortions to get what you want; Hammer and
> ZFS are different beasts, but what you want to do is expressed in
> terms of ZFS features, which is why there isn't a straight answer.

Actually, I was referring to raidz2 as an example. My main goal was a
software RAID6. If I can do that with vinum, good. If vinum allows me
to grow the file system, even better!


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