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>> I ran into an out of memory problem. The first mention of it in the |
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>> kernel log is "mysqld invoked oom-killer". I haven't run into this |
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>> before. I do have a swap partition but I don't activate it based |
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>> on something I read previously that I later found out was wrong so |
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>> I suppose I should activate it. Is fstab the way to do that? I |
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>> have a commented line in there for swap. |
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>> |
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>> Can anyone tell how much swap this is: |
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>> |
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>> /dev/sda2 80325 1140614 530145 82 Linux swap / |
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>> Solaris |
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>> |
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>> If it's something like 512MB, that may not have prevented me from |
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>> running out of memory since I have 4GB RAM. Is there any way to |
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>> find out if there was a memory leak or other problem that should be |
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>> investigated? |
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> |
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> To activate swap, put a line in fstab like so: |
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> |
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> /dev/sda2 none swap sw 0 0 |
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> |
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> However, you do not want to use it. it is not the life-saver some |
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> howto authors on the internet claim it to be. |
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> |
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> When a linux machine hits swap, it does so very aggressively, there is |
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> nothing nice about it at all. The entire machine slows to a |
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> painstaking crawl for easily a minute at a time while the kernel |
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> writes pages out to disk, and disk is thousands of times slower than |
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> RAM. |
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> |
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> It gets so bad that you can't even run a shell properly to try and see |
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> what's going on and kill the actual memory hog. |
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> |
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> My personal rule of thumb: if you hit swap, the bad thing has already |
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> gone very very south, usually to the point where you can't do much |
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> about it and it's already too late. Besides, that bastard deomon spawn |
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> of satan called the oom-killer is likely about to kick in and REALLY |
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> make your day. Anyone else notice how oom-killer seems to be hard |
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> coded to zap the most inconvenient process of all?..... |
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> |
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> What you need to be doing is monitor your memory usage during normal |
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> conditions and deal with issues before they become problems. |
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|
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Hi Alan, I think it was your advice I took a long time ago when I |
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stopped installing new machines with a swap partition and disabled it |
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on my already-installed machines. Some time later, others on this |
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list caught wind of what I'd done and told me I was an idiot. Is |
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there a consensus on this? If the drawbacks and advantages of using |
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swap cancel each other out, I won't use it. |
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|
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- Grant |
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