Tag Archives: linux

Linux 2.6.29

Posted on March 24, 2009 by Domas Mituzas

2.6.29 was released. I don’t usually write about linux kernel releases, thats what Slashdot is for :), but this one introduces write barriers in LVM, as well as ext4 with write barriers enabled by default. If you run this kernel … Continue reading →

Posted in mysql | Tagged , , | 2 Comments

iostat -x

Posted on March 11, 2009 by Domas Mituzas

My favorite Linux tool in DB work is ‘iostat -x’ (and I really really want to see whenever I’m doing any kind of performance analysis), yet I had to learn its limitations and properties. For example, I took 1s snapshot … Continue reading →

Posted in mysql | Tagged , , | 18 Comments

mmap()

Posted on August 17, 2008 by Domas Mituzas

I’ve seen quite some work done on implementing mmap() in various places, including MySQL. mmap() is also used for malloc()’ing huge blocks of memory. mmap() data cache is part of VM cache, not file cache (though those are inside kernels … Continue reading →

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Notes from land of I/O

Posted on August 11, 2008 by Domas Mituzas

A discussion on IRC sparkled some interest on how various I/O things work in Linux. I wrote small microbenchmarking program (where all configuration is in source file, and I/O modes can be changed by editing various places in code ;-), … Continue reading →

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I/O schedulers seriously revisited

Posted on February 5, 2008 by Domas Mituzas

The I/O scheduler problems have drawn my attention, and besides trusting empirical results, I tried to do more of benchmarking and analysis, why the heck strange things happen at Linux block layer. So, here is the story, which I found … Continue reading →

Posted in mysql | Tagged , , , , | 9 Comments