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Stupid Data Center Tricks
jcatcw writes "A university network is brought down when two network cables are plugged into the wrong hub. An employee is injured after an ill-timed entry into a data center. Overheated systems are shut down by a thermostat setting changed from Fahrenheit to Celsius. And, of course, Big Red Buttons. These are just a few of the data center disasters caused by human folly."
The summary reads like a digg post, and has two different links that, in actuality, link to the exact same thing.
This needs some fixin'.
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
Can this really happen easily? I thought for really ugly things to happen, you need to have switches (without working STP, that is).
Where I work a couple years ago one of the non-technical people decided to plug a router into itself. Ended up bringing down the whole network for ~25 people in a company which depended on the Internet (Internet marketing company).
Unfortunately one of the tech guys figured it out literally as everyone was standing by the elevator waiting for it to take us home. We were that close to freedom :(
Our entire network was brought down a few years ago when a student plugged a consumer router into his dorm room's port. Said router provided DHCP, and having two conflicting DHCP servers on the network terminally confused everything that didn't use static IPs.
Took our networking guys hours to trace that one down.
Hail Eris, full of mischief...
E pluribus sanguinem
In the summer of 2000 I worked at Quad/Graphics (printer, at least at that time, of Time, Newsweek, Playboy, and several other big-name publications). I was on a team of interns inventorying the company's computer equipment -- scanning bar coded equipment, and giving bar codes to those odds and ends that managed to slip through the cracks in the previous years. (It's amazing what grew legs and walked from one plant to another 40 miles away without being noticed.)
One of my co-workers got curious about the unlabeled big red button in the server room. Because he lied about hitting it, the servers were down for a day and a half while a team tried to find out what wiring or environmental monitor fault caused the shutdown. That little stunt cost my co-worker his job and cost the company several million dollars in productivity. It slowed or stopped work at three plants in Wisconsin, one in New York, and one in Georgia.
The real pisser was the guilty party lying about it, thereby starting the wild goose chase. If he had been honest, or even claimed it was an accident, the servers would have all been up within the hour, and at most plants little or no productivity would have been lost.
The reality: a 20 year old's shame cost a company millions.
- run thinnet lines along the floor under people's desks, for them to occasionally get kicked and aggravate loose crimps, taking entire banks of computers (in a different wing of the building) off the LAN with maddening irregularity
- plug a critical switch into one of the ups's "surge only" outlets
- install expensive new baytech RPMs on the servers at all remote locations, and forget to configure several of the servers to "power on after power failure".
- on the one local server you cannot remote manage, plug its inaccessible monitor into a wall outlet
honorable mention:
- junk the last service machine you have laying around that has a scsi card in it while you still have a few servers using scsi drives
I work for the Department of Redundancy Department.
It's very disturbing and you'll see why these things happen.
RIP America
July 4, 1776 - September 11, 2001
192.168.x.x? That's amazing. I've got the same IPs on my luggage.
When he arrived, most of the staff had gone home and the skeleton IT staff didn't want to hang around. So, they sent him away on the basis that his work wasn't "scheduled".
Everybody came back on Monday to find totally fried servers.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
How can this leave out the standard cascade failure scenario?
Trying to achieve redundancy, someone gets what they think is worst-case-30A of servers with multiple power supplies, plugs one power supply on each into one PDU rated 30A, one power supply into the other.
They may or may not know that the derated capacity of of the circuit is only 24A, the data center is unlikely to warn them as they only appear to be using 15A per circuit at most.
Anyway, something happens to one of the PDUs and the power is lost from it. Perhaps power factor corrections (remember the derating?) and cron jobs running at midnight on all the servers that raise the load high simultaneously. Maybe just the failure of one of the PDUs that was feared, causing the attempt at "redundancy".
In any case, all of the load is then put on the remaining circuit, and it always fails. The whole rack loses power.
Covering those power strip buttons with a hardened glob fixing them in the "on" position is what an electric glue gun is for.
Those data centers in the article sound huge, some may even have up to ten servers!
The old tape machines (six foot tall) used to put out a tremendous amount of heat. Space is at a premium, so in the mainframe room the drives were normally put edge to edge,
with one pushing air in and the other pulling air out. The machines had two 10-12" fans per unit, so stacking two or three units was fine. One site had so many machines side to
side (over 7), the air coming out the last machine regularly set things on FIRE. It was not uncommon for the machine to ignite lint going through the stack, with it coming out the
end as a small explosion like dust in a grain silo explosion. A fire extinguisher was kept on hand, and the wall eventually got a stainless steel panel because it was so common.
When I was IT manager for a big retail mfg we had a cross-country move from the SF bay area to TN (closer to shipping hubs and lower tax rates). I was hired for the new plant, and I was there setting up everything (I did not know the company knew next to nothing about technology) and the last thing shipped before the company shutdown for the move was ship the data server via 2 day FedEx. The CFO packed it up and shipped it out, as the driver pulled away from the bay the server fell off the bumper and onto the cement. They picked it up (looking undamaged in it's box). When I opened it there was a shower of parts. A HD drive had detached from the case but not the cable and had swung around in that case like a flail. CFO had NOT INSURED the shipment or taken anything apart. That and much more to save $50 here and there.
6.8SPC TR of 550, l xwind at 6, drift rt at 26" drops 77". AT has 503 ft-lbs at 1403 fps. FT 0.86
Back when I worked for Boeing, we had an "interesting" condition in our major Seattle area data center (the one built right on top of a major earthquake fault line). It seems that the contractors who had built the power system had cut a few corners and used a couple of incorrect bolts on lugs in some switchgear. The result of this was that, over time, poor connections could lead to high temperatures and electrical fires. So, plans were made to do maintenance work on the panels.
Initially, it was believed that the system, a dually redundant utility feed with diesel gen sets, UPS supplies and redundant circuits feeding each rack could be shut down in sections. So the repairs could be done on one part at a time, keeping critical systems running on the alternate circuits. No such luck. It seems that bolts were not the only thing contractors skimped upon. We had half of a dual power system. We had to shut down the entire server center (and the company) over an extended weekend*.
*Antics ensued here as well. The IT folks took months putting together a shut down/power up plan which considered numerous dependencies between systems. Everything had a scheduled time and everyone was supposed to check in with coordinators before touching anything. But on the shutdown day, the DNS folks came in early (there was a football game on TV they didn't want to miss) and pulled the plug on their stuff, effectively bringing everything else to a screeching halt.
Have gnu, will travel.
Ah, the memories! Here are some of the stories I've heard and or witnessed over the years.
THE WEBSITE'S DOWN!!!
http://www.youtube.com/watch?v=W8_Kfjo3VjU
Wherever You Go, There You Are
My favorite was at a big office building. An electrician was upgrading the fluorescent fixtures in the server room. He dropped a washer into one of the UPSs, where it promptly completed a circuit that was never meant to be. The batteries unloaded and fried the step-down transformer out at the street. The building had a diesel backup generator, which kicked in -- and sucked the fuel tank dry later that day. For the next week there were fuel trucks pulling up a few times a day. Construction of a larger fuel tank began about a week later.
Stop-Prism.org: Opt Out of Surveillance
I had fun with a company awhile back. They are about 300 employees and ~90mil/year, so this is a small corporation.
Anyway, the company was trying to get a VPN tunnel established to their China office, and they were having a hell of a time at it. The employees on the China side had no IT experience so everything was done remotely.
It just so happens that one of the Chinese employees was recruited to make a change to the PIX firewall on the China side in order to get everything working. To our astonishment, it worked, and we had a secure VPN tunnel established.
The problem was accounts in the US started to get locked out, alphabetically, every 30 minutes. Our Active Directory was getting tons of password crack attempts from inside our internal network. I was using LDAP to develop an application at the time, so naturally I was suspect for causing all these lockouts.
Fast-forward a week. We look at the configuration of the Chinese firewall and it allowed all access from any IP address on the Chinese side. In other words, crackers were trying to get into our systems through our VPN tunnel in China. In effect, our corporate LAN had been directly connected to the Internet. Once we figured that out, I was free to go back to work and the network lived to see another day, but that incident caused major trouble for all our employees.
Moral of the story: Don't trust a Chinese firewall.
Good judgement comes from experience. And most experience comes as a result of bad judgement.
/dev on a *nix box), then having to watch for about 45 minutes while my users' PIDs disappeared. I'll never forget that red-faced moment of knocking on my boss's door and letting him know he might want to leave his phone off the hook for the next hour...
Just about anyone who has been in the line of fire as sysadmin for long enough will recall some ill-concieved notion that caused untold trouble. Since my earliest experience with commercial computers was in a batch-processing environment, my initial mishaps rarely inconvenienced anybody other than myself. But I still recall an incident much later (early '90s) when I inadvertently managed to delete the ":per" directory on a Data General mainframe (more or less equivalent to
I was employed in a 50 employees publicity company. They have a couple of offices across the country and need to share a filesystem through WAFS. The main repository for the WAFS was running off a USB drive, connected to the server using a wire too short. I pointed the problem multiple times to my IT boss (no IT background what so ever) without success, tried to talk the issue to the owner of the company, without success, and one day tyhe worst happenned. The USB controller of the drive fried and we lost the last day of work. Thw windows server system went AWOL. It took an external consultant 3½ days to rebuild the main server, which was running the AD, WAFS, Exchange and our enterprise database. It costed us an account worth 12 MILLIONS $. The big boss then hired consultants and gave them over a thousand box to get her told the exact same thing I pointed to 3 months earlier when I audited the IT infrastructure. Two months later she comes top me and ask me how much it would cost to have a bullet-proof infrastructure. I told her to invest arounbd 80K in virtualisation solution with scripts to move VM around when workload changes and go with a consolidated storage with live backups and replication. It was too expensive. Another three months pass, she hire some consultants, gave them another thousands $ to get told basically the same thing I told her 3 months earlier... Than is where i quitted.
Tomorrow is another day...