On Tue, 17 Nov 1998 15:30:42 -0500, Rick Clark <[log in to unmask]>
wrote:

>Great!! That's not what I want to hear as I move towards the 9000
>platform.
>
>Here's something I wonder the 9000 will be able to handle. We just
>experienced a brown out at about 2:30. Our UPS kept the HP3000 up and
>running through it all. Then at about 3:00, the power went completly
>out. Our HP3000 was still running, and we were able to bring it down
>with no problems. We were up and running in less than 10 minutes after
>the power came back on. Take that 9000. At least I hope you can...
>

Well "recent" HP-UX versions include something called VxFS, or JFS
(journalled file system). Traditional UNIX file systems keep disk
directory structures in memory so updating them is fast (which was
apparently much easier to write than a actual fast, reliable
disk-based directory). Anyway, JFS adds an "intent log" to this
process. This avoids the need to do an fsck on your journalled file
systems when the machine died ungracefully. it shortens recovery times
from hours to minutes.

Some people thought that this meant that HP-UX now had a Transaction
Manager-type capability that protects your data. This is INCORRECT.
JFS only protects the directory and other metadata. It does NOT
protect the contents of individual files. JFS makes sure you can find
all your files. However, all your files may be junk now. :)

Of course, the answer is to hook a sufficient UPS to your 9000 such
that the 9000 goes thru an orderly shutdown when the battery reserves
drop below a certain threshhold.

Someone else mentioned getting Mirror/UX to protect your data. Nah ...
buy a Model 20 disk array or two instead. You get better performance,
more RAID flexibility, and you don't have to pay for Mirror/UX (which,
to us anyway, can get pretty expensive...)

My 2 cents, of course. :)
---

Mark Landin                   "For anyone who was never good at
T. D. Williamson, Inc.         anything, technology has been a
UNIX Sys. Admin                real boon" --- my mom