[QUOTE="Mr"] [QUOTE] Having worked[1] on one of the largest HP-UX site in Europe it seemed no less/more reliable then any other version of unix they used [2] and it's used on systems where downtime is *not* an option. But hell what would I know.[/QUOTE] Standard HP-UX needs downtime for kernel parameter changes, filesystem modifications so shouldn't be used where downtime is *not* an option,[/QUOTE] My experience of managing the world's largest optical network management system (on HP-UX) is that where downtime is not an option, there are superb disaster recovery solutions in place, including geographic redundancy, so it's easy to take down one machine from the cluster for, say, kernel parameter changes. [QUOTE] I think you'll find the HP-UX admins in at 2am and on Saturdays to take the systems offline, unlike their AIX and even Linux bretheren.[/QUOTE] I only ever worked extraordinary hours when (a) I was monitoring while the node monkeys did work on the transmission kit (b) when there was an upgrade went on longer than anticipated due to the NM software being untested and, basically, shit.