On Thu, 07 Jul 2011 08:11:36 -0700, Jeff Liebermann wrote:

On Thu, 7 Jul 2011 02:05:58 +0000 (UTC), Meat Plow
wrote:

On Wed, 06 Jul 2011 17:28:01 -0700, Jeff Liebermann wrote:

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.

Redundancy means cover thy ass. Any way you can.

Well, ok. I'll use your definition. If I have two identical drives,
each 90% reliable, how reliable are two of such drives?
0.9 * 0.9 = 0.81 = 81% reliable.
If I have a RAID array of 4 drives, with the same reliability, it would
be:
0.9 * 0.9 * 0.9 * 0.9 = 66%
The data might still be safe or recoverable, but limping along with one
drive is not acceptable. Even worse is that identical drives tend to
fail identically. The point where I gave up on the RAID idea was when I
had 2 out of 4 drives fail within 2 weeks, and there were indications
that the other 3 drives (RAID 1+0 with parity 5 drive array) would soon
follow. I was lucky was able to replace all the drives before they all
failed.

I had previously purchased several identical drives as spares when the
RAID array was first installed. The plan was to use them as
replacements in order to keep the rotational sync problem to a minimum.
The drives just sat on my shelf. When I crammed two of them into the
RAID array as replacements, they started showing signs of impending
failure. Just what I didn't need was a fundamentally unreliable array
of drives.

Had my fair share of the
Dell PERC2 RAID controller battery failures and complete loss of RAID
containers. Dead Fujitsu drives on the second day of service for a
Poweredge server. I could go one and one...

Argh. The AMI or LSI Logic controllers use a proprietary parity
algorithm that is just short of being encrypted. Of course, LSI Logic
won't divulge the details and Dell claims it's not a problem. Various
companies have reverse engineered the system thus allowing uses to make
a backup. You can always tell that there's a problem, if there are
companies specializing in recovering RAID data:
http://www.raidrecoverylabs.com/dell_data_recovery/
http://www.raidrecoveryguide.com

The one most remembered was a Poweredge controller with RAID 5.
The owner shut it down over the winter against advice and without my
knowledge. It's a golf course and vacated for 5 month a year.
I was unaware of the battery problem in the controller but that
didn't matter. Once the configuration is gone in the controller
there is no way to restore the lost container. Luckily they did
back their data up the week before shutting the server down. I created a
new container, installed W2K Server and the point of sale software
and SQL server. Some ODBC stuff, their sales and price data restored
and they were ready to reenter any changes made after the backup.
It was a fairly elaborate system for me. Touch screen terminals
and receipt printers for 4 point of sales and two outdoor starter
gazebos. A connection to a Windows XP PC running two phone cards
for dial in course reservation bookings. So there was quite a bit going
on. I re-did the entire system previously running Novell 3.12, TCNS
and DOS workstations. Also added a 2 channel 64k ISDN to the network. The
fastest they could get at the location.


Most I remember about Xenix it was an AT&T product I think.

Nope. Originally a Microsloth product, which was almost immediately
taken over by SCO (Santa Cruz Operations). At one point, it was also
sold by IBM. I still have one customer using Xenix 2.3.4 on a 386.
Totally reliable for late 1980's character based applications.

You're probably thinking of AT&T Unix SysV and others.

I knew I read it somewhere in the past:
Xenix is a version of the Unix operating system, licensed by Microsoft
from AT&T in the late 1970s. The Santa Cruz Operation (SCO) later
acquired exclusive ...

AT&T was the original developer.


Mine is all
NT4 server, NT4 Hydra, NT4 Terminal Server with Exchange, Citrix
Metaframe,
Windows Server 2k, 2003, Novell 3xx, 4.xx. BSD and linux for routers
(before the hardware appliances) Cobalt Cube mail servers, managed
switches, fiber the whole shebang.

All for one company? Seems like a rather strange mix of server
operating systems. Ever consider reducing the number of OS's in order
to simplify maintenance?

No no no no no. Just my experience, and a considerable amount of
experimentation.

I had to work around the needs of the network, the current business
software, and if that software could be ported over to Windows.
I wanted to do away with all the Novell stuff but a lot of people were
running their business suites that were not fully ported for Windows yet.
I remember one company that tried to switch their Macola suite over to
Windows. A rep from the company came with her own server to do the
conversion. It failed. Macola makes you sign a release stating they
can't be sued for problems with their product. So we gave up on the
switch. I got fed up with the CEO and CFO of the company wanting me
to try to figure out all these damn ODBC connections so they could fax
stuff directly from the CAD department and a long list of other near
impossible database crap of similar nature. Some companies charged a
couple hundred bucks for each ODBC driver. And they wouldn't send you
a sample to see if it would work without paying the full price.
I got tired of all the torture, free support, gray hairs and turned
that client over to a friend who had some resources I didn't in writing
database stuff.

Most of my nets were hybrid Novell/Windows. I sent a message to the
Novell clients to inform upon an impending shutdown so people could save
their work. Hell I charged by the hour so it didn't matter to me how
long I waited for everyone to back out.

I mostly charge by the hour, but I also had some service contracts. My
problem was that I would usually book several service calls per day. An
extra hour at the morning customer, would cut into the time I had
allocated for the later customers. I didn't care if it took longer, but
only if I could leave at my predicted time. Also, if I left it to the
customer to declare that the computer was can't be shut down, it would
be more like several hours delay.

Whatever works. We didn't have contracts. Hell most of these clients
didn't even have a budget for IT. So I usually designated the most
computer savvy person with the highest worker ranking to do scheduled
stuff an proper server reboots when needed.

My mistake. I had been thrust
into Novell because the Novell guy quit after only two weeks training
me.

I got into Novell when all the local consultants decided the company was
a loser after Novell unilaterally tweaked the relationship in their
favor. I decided to give it a try, which worked until Novell started
insisting on expensive certifications and bizarre financial
requirements. I bailed, but managed to keep a few Novell customers. Mid
1990's I think, maybe.

I never got past 4.xx. A couple non-profit organizations were running it
on Compaq Prosignia and Proliant. Had one commercial running two Proliant
cluster servers. Once I saw where version 5 was going I bailed.

Them people at the
steel plant expected me to be their god.

Naw, I don't look good in a toga.

The receptionist at one printing firm used to bow to me when I walked
through the front door. Windows 2K, NT4 servers in the back for the
Appletalk storage in CAD to printing. They made custom banners up to 12
feet wide IIRC.

Everyone had their own special need. I'm trying to link Macola ODBC,
Pervasive SQL workstation clients with MS ODBC with third party modules,
FaxPress functions for faxing and emailing out of Exchange with one
keystroke. Stuff like that. Nightmare.

That is a nightmare. I've seen it happen and do everything I can to
prevent application proliferation. Every new hire has their own
favorite application that just has to be installed immediately.
Fortunately, I was dealing mostly with Unix/Xenix boxes, where choices
of the major applications were fairly limited. At the time, I would
have sold my immoral soul for a VM type system, where I could sequester
individual users and their strange applications in their very own
private pig pen, and let them wallow in their own bugs.

I really got to hate these CFO/CEO that had some computer savvy and
wanted stuff to integrate this and that way. I was happy to dream at night
about the way it was with one Novell server and diskless workstations
booting off the server images. Once windows 98, W2K and XP it was utter
chaos.



--
Live Fast Die Young, Leave A Pretty Corpse