On Wed, 6 Jul 2011 22:23:35 +0000 (UTC), Meat Plow
wrote:
Redundancy is your friend.
Well, not exactly. Cover thy ass, backups, and disk images are best.
RAID, mirroring, and tape backup are the road to hell. Been there,
done them all, and learned some really expensive lessons.
I learned that
working on live computer systems for commercial clients that ran 3 shifts
of CNC.
Ugh. Don't remind me. I had a customer running some APT program on
Lisa Xenix. They had two Lisa machines so theoretically, I was
protected. However, the system as stable as a house of playing cards.
Since Lisa Xenix wasn't getting updated, I didn't have that nightmare.
Instead, I had hardware failures, corrupted filesystems, and just
plain bad luck. So, to cover myself, it was:
find . -depth -print | cpio -odB | compress | \
rcmd machine_name "dd of=/dev/rStp0"
before attacking. That saved my posterior more times than I care to
admit.
Take them down for half an hour is a big deal.
I tried every variation of being considerate and nothing worked. Even
showing up at 2AM to do maintenance at the local hospital was a
problem. So, I went the other direction. I decided that I would set
the maintenance schedule and to hell with anyone that dared to
interfere. After checking with management, I would send out email and
post signs indicating that at 5:00PM, the servers would be down for
maintenance. At 5:00PM exactly, I would invoke the sacred
incantations:
sync; sync; haltsys
and wait for the screaming to start. Invariably, someone had files
open, or unsaved data. I didn't care. Trust me, it works far better
than trying to be considerate.
Screwing something
up big time and not having a redundancy plan to return before the upgrade
will lose you the client. Happened to me once on an old Novell 3.10 server
running a golf course point of sale system. Upgraded the OS to 3.12 and it
died in the process. Later figured out after a couple hours that the dos
partition was full and that's where the boot files are.
Ummm.... I think you mean 3.11. There was no 3.10. Next time, check
your disksapce with Volinfo and clean up marked for deletion files
with the purge command. Going from Novell 3.11 to 3.12 was a not
major project but did require having quite a bit of empty disk space.
incidentally, I have a (non-paying) customer running 3.12 on a 4GB
drive.
Deleted some
orphaned files, re-ran the upgrade and all was fine. Didn't lose the
client but they spent a lot of time entering sales they wrote down on
paper back into the system. I couldn't charge my time ethically so I lost
300 bucks. That taught me a good lesson.
Well, if you only did that once, it's probably not a major disaster.
In my case, I'm always finding new ways to burn my time. Todays mess
is a classic. Virus infected laptop. Customer wants me to save some
of the junk in the Documents dumpster. She said it was ok to reformat
and start over, so I didn't see any reason to remove the virus. I
copy the files to a USB flash drive, and shove the flash drive into my
main office machine with the intent of scanning for viruses. I didn't
have to scan as autorun.exe conveniently installed the virus on my
machine. It took me about two hours to get rid of it (mostly spent
scanning). Argh.
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
#
http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS