Re: I/O Watchdog Daemon

I don't have any of your hardware, but I'd like to give you some thoughts:

You're using the SSD for performance, but if it hangs, performance is worthless. Have you tried to use cron to reboot every Saturday night (or whenever it is low usage ). Immediately, stress is reduced. If it needs to be done daily, so be it. I have done this successfully on an AIX box, so it should work with Linux.
Have you tried the Knoppix in memory Linux. Use the SSD for performance, but reboot when the SSD fails. The operating system is in memory and on the read only DVD/CD, so the reboot should work without needing anything from the SSD.

Perl depends on the operating system, so if the OS is failing, Perl may also fail and your no better off.

If at the moment this is a 'desperate situation', make it easier on your self by using the system to ease your life.

Good Luck!

"Well done is better than well said." - Benjamin Franklin

Comment on Re: I/O Watchdog Daemon

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Re^2: I/O Watchdog Daemon by IdleResonance (Acolyte) on Aug 22, 2012 at 15:54 UTC
I have considered doing weekly reboots. It would cause unwanted downtime, but on the other hand it is far cleaner and safer to do "shutdown -r now" than "reboot -nf" :) I still might do this -- or both. Not sure what you mean about using Knoppix. I have no hands on the box. It's 2000 miles away and I don't have out of band management. I wouldn't say that the OS is failing... In this state, the kernel is fine and processes are still responding (so long as they're not accessing the SSD). Since the daemon is running in memory, then it should be fine. It's the potential EIO failures that I want to detect that are the primary issue and if I can trigger the reboot -nf without any disk I/O then I think it will be an acceptable band-aid until the situation can be resolved permanently. Thanks!	[reply]
Re^3: I/O Watchdog Daemon by flexvault (Monsignor) on Aug 22, 2012 at 17:05 UTC
IdleResonance, I wasn't trying to solve your problem, but to help you start 'thinking outside the box'. You said you do not know how to test the Perl solution. For me, if I can't test a solution, then I wouldn't depend on it working, but that's me. I have never used a SSD, but I have been told that they can reboot in less than a minute. Since you have the equipment, you know that answer. Only you can evaluate and weight the value of a minute of downtime versus unpredictable downtime. But I think you're on your way! ( No giggling AM! ) Good Luck! "Well done is better than well said." - Benjamin Franklin	[reply]
Re^2: I/O Watchdog Daemon by Anonymous Monk on Aug 22, 2012 at 13:42 UTC
Perl may also fail and your no better off. "his" no better off? "his" what? You are looking for "you're" meaning "you are" not "your" meaning "belonging to you" This is like the third or fouth time I noticed you're typo and duty called :)	[reply]
Re^3: I/O Watchdog Daemon by flexvault (Monsignor) on Aug 22, 2012 at 13:52 UTC
Dear Monks, But you understood! Personally, I find programming and grammar to use opposite sides of my brain, so today I'm programming. I also find that I type 'perl' for 'per' all the time now. Thank you "Well done is better than well said." - Benjamin Franklin	[reply]