Re: Request for opinions - gvinum or ccd?

On Sun, May 31, 2009 at 4:59 PM,  <xorquewasp@googlemail.com> wrote:
> There is one last thing I'd like clarified. From the zpool
> manpage:
>
> =C2=A0In order =C2=A0to take advantage of these features, a pool must mak=
e use of
> =C2=A0some form of redundancy, using either mirrored or raidz =C2=A0group=
s. =C2=A0While
> =C2=A0ZFS =C2=A0supports running in a non-redundant configuration, where =
each root
> =C2=A0vdev is simply a disk or file, this is strongly discouraged. =C2=A0=
A =C2=A0single
> =C2=A0case of bit corruption can render some or all of your data unavaila=
ble.
>
> Is this supposed to mean:
>
> =C2=A0"ZFS is more fragile than most. If you don't use redundancy, one
> =C2=A0 case of bit corruption will destroy the filesystem"
>
> Or:
>
> =C2=A0"Hard disks explode often. Use redundancy."

Unless you specify mirror or raidz on the create/add line, zfs (in
essence) creates a RAID0 stripe of all the vdevs.  Hence, if a single
drive dies, the whole thing dies.  Just like in a normal
hardware/software RAID0 array.  Nothing special or new here.

Just like "normal" RAID, unless you add redundancy (RAID1/5/6) to a
stripe set, losing a single disk means losing the whole array.
--=20
Freddie Cash
fjwcash@gmail.com
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