ext4 journal mode and speed

Mr. Alex · 2010-12-02 10:16:13

I was searching via Google and found nothing... ext4 has 3 journalling modes. They have different performances. But performances of what - reading and writing or writing only? Is reading speed of writeback and ordered modes the same?

I know files have access time and date which changes after you read the file. But does journalling mode affect it?

karol · 2010-12-02 10:33:02

Found this: http://git.kernel.org/?p=linux/kernel/g … 28125700bb

Mr. Alex · 2010-12-02 11:44:40

This difference of read speed is with patch, not original ext4 driver. But thanks.

thestinger · 2010-12-02 17:38:09

that's part of the kernel code now, you can disable the journal if you want

the "default" column is with ordered, writeback will be slightly faster, and then without a journal at all is faster

as long as you use noatime, the read speed of each is the same

rusty99 · 2010-12-02 17:59:01

Although this is aimed at ext3 there's a decent description of the 3 data=? in this paper http://www.sun.com/software/whitepapers … rmance.pdf
Some performance benchmarks near the end iirc.

Arch Linux

#1 2010-12-02 10:16:13

ext4 journal mode and speed

#2 2010-12-02 10:33:02

Re: ext4 journal mode and speed

#3 2010-12-02 11:44:40

Re: ext4 journal mode and speed

#4 2010-12-02 17:38:09

Re: ext4 journal mode and speed

#5 2010-12-02 17:59:01

Re: ext4 journal mode and speed

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