Bill Lancaster wrote:
>
(lots of good stuff snipped)
> 2.  Better system resiliency.  Some disagree with this but most of the time,
> if you lose a volume which belongs to a user volume set the system won't go
> down.  Occasionally, it will, but generally it won't.

Just commenting about the 'resiliency' or 'high availability' aspect of
user volume sets:

1) Separating your data onto one (or preferably more) user volume set(s)
buys you a 'smaller unit of reload' in case of a disc failure where the
disc has to be replaced, i.e. recovery times are shorter.

2) Separating different applications onto different user volume sets
(assuming your system's user use more than one application) will mean
that the applications on the non-affected volume sets will at worst
be available directly after a reboot.

In general there is no way the operating system can handle all
possible hardware errors, so that it would not crash or hang.
It really depends on which disc operation is happening at the
time, and how the hardware error mainfests itself. Sometimes
you will just have a controller 'falling silent', sometimes
information critical to the OS will be corrupted, so the system
aborts.

Using Mirrored Disc/iX can really buy your more uptime for most
cases, but you should not expect 100% bulletproofness for there
are rare cases of undetectable corruptions.

Goetz.