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Crash-only Linux?

Crash-only Linux?

Posted Jan 29, 2010 8:40 UTC (Fri) by cpeterso (guest, #305)
Parent article: A module for crashing the kernel

Maybe now is the time for the Linux kernel to adopt a "crash-only" shutdown policy [1]. If your application or the kernel always shuts down gracefully, then you are not really testing your recovery code (and you are wasting time cleaning up resources). Always crashing on shutdown will force developers to consider error-handling and recovery from (inevitable!) crashes.

[1] LWN: "Crash-only software: More than meets the eye"

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Crash-only Linux?

Posted Jan 29, 2010 17:50 UTC (Fri) by MattPerry (guest, #46341) [Link]

I couldn't agree more. I yearn for the days when the OS was always in a state where it could be powered down. Are you done using your computer? Just turn the power switch off. Now we have to "shutdown" which is a pain and takes time. I'd prefer the system was always in a state ready to be turned off safely, even it if took longer to operate.

Crash-only Linux?

Posted Jan 29, 2010 17:56 UTC (Fri) by corbet (editor, #1) [Link]

Interesting...the only machine I've ever used that could just be turned off was a Data General Nova with core memory; turn it on, and it just picked up where it left off. Every other system I've ever used was unhappy with an abrupt turn-off.

Crash-only Linux?

Posted Jan 29, 2010 18:08 UTC (Fri) by clugstj (subscriber, #4020) [Link]

DOS never had a "shutdown" command AFAIR. When you were done w/ your IBM PC, you flipped the power switch - of course, you never did this while it was writing to your (floppy) drives.

Crash-only Linux?

Posted Jan 29, 2010 18:33 UTC (Fri) by dlang (subscriber, #313) [Link]

.. or when you were writing to your hard drive.

you can do this today with linux, just mount all your filesystems syncronously and you will have a system that you can shutdown at any time that it's not writing to your disk.

you will also have a system that you will find unusably slow, you don't realize how much you gain from not waiting for writes to hit disk before continuing.

Crash-only Linux?

Posted Feb 1, 2010 13:29 UTC (Mon) by Cato (subscriber, #7643) [Link]

Actually it's quite viable to use synchronous writes on filesystems - that's how I set up all my Linux systems, having had some major hassles with data corruption on ext3. There is some performance hit but it's still a lot faster than my Windows XP laptop which has about the same CPU and RAM.

See for the details - however, I now think that the only problem is not having synchronous writes, and that LVM is largely OK. This makes sense given that LVM is used a lot in enterprise Linux servers.

Crash-only Linux?

Posted Jan 30, 2010 16:57 UTC (Sat) by filipjoelsson (guest, #2622) [Link]

AFAIR you had to park the harddrive on most systems with such a device back in the day, so that wasn't universal. The Commodore 64 OTOH, was an instant off computer. ;)

Crash-only Linux?

Posted Jan 30, 2010 18:03 UTC (Sat) by SimonKagstrom (subscriber, #49801) [Link]

Only if you weren't saving something to the tape!

Anyway, you can use halt -f to achieve the same thing you a Linux computer. You can probably also bind it to the ACPI event when the power button is pressed to get the desired behavior. The less brave among us would do a sync first :-)

Crash-only Linux?

Posted Jan 30, 2010 18:19 UTC (Sat) by MattPerry (guest, #46341) [Link]

My Amiga would allow you to to turn it off when you were done. No shutdown needed. This was a very unix-ish, fast, multitasking OS.

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