Tag Archives: io

On file system benchmarks

Posted on June 30, 2009 by Domas Mituzas

I see this benchmark being quoted in multiple places, and there I see stuff like: When carrying out more database benchmarking, but this time with PostgreSQL, XFS and Btrfs were too slow to even complete this test, even when it … Continue reading →

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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 →

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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 →

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On SSDs, rotations and I/O

Posted on November 9, 2008 by Domas Mituzas

Every time anyone mentions SSDs, I have a feeling of futility and being useless in near future. I have spent way too much time to work around limitations of rotational media, and understand the implications of whole vertical data stack … 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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On blocking

Posted on June 20, 2008 by Domas Mituzas

If a process has two blocking operations, each blocking other (like, I/O and networking), theoretical performance decrease will be 50%. Solution is very easy – convert one operation (quite often the one that blocks less, but I guess it doesn’t … Continue reading →

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Shameless ad

Posted on May 15, 2008 by Domas Mituzas

“The Sun Fire X4240, powered by the AMD Opteron 2200 and 2300 processor series, is a two-socket, 8-core, 2RU system with up to twice the memory and storage capacity of any system in its class. It’s the first and only … 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 →

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