Fail

posted 5 years ago by Ben Cordero

There's nothing like a fresh start. Unfortunately last weekend's reinstall of juniper went less happily than I expected.

A source based distro notices problems quickly. It starts as simple compilation errors. The linker being unable to create a final executable, or being unable to spawn a new shell instance. A bunch of random errors in tasks that usually work.

You start to question your sanity in choosing this OS, it's been historically reliable. It must be some other reason. But deep down the probability counters are incrementing towards the conclusion that means that no fancy fingerwork will fix. Presenting, The Hardware Problem.

1/. Admit that you're going to have downtime.

It broke. It didn't work. Now something needs to be done.

There are multiple possibilities that you can do at this stage. The Developer in me would go through some logs, find the config typo and increment the version string.
The Tester in me would keep the system in a confused state and grab as much persistent data as possible.

This is a setup that should just work™. So the SysAdmin in me takes over. Reboots into memtest and starts poking around.

2/. Diagnose the problem

Memtest reports errors. I knew there were some, but it's nice to confirm this properly. Better fire up the external music player, it's going to be another hour or so of hunting down the specific RAM chip. Then praying that it's only one.

Extra points if you work around the broken bios because the POST was loaded into faulty RAM chips on your positive diagnostic run. oops.

3/. Put in a temporary fix

In a more prepared environment there would be a hot standby (just reprogram the load balancers), or replacement hardware in a nearby cupboard. This is a home system, so just remove the broken chip, and run with what's left.

4/. Resume what you were doing

The problem was fixed. All is right with the world. We can now continue from where we started.
Oh wait, LVM is complaining about IO errors now.

5/. Back into diagnostic mode

Fire up the LiveUSB environment again. This runs in RAM (now proven to be safe). smartctl to the rescue.

3 HDDs, 1 has 14 errors logged, and the other 2 are about to fail. dmesg reports that they're taking a little longer to start up too.

5/. Resign a sigh

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