BTRFS, mount options and virtual machines: an in-depth look

Written by Gionatan Danti on . Posted in Linux & Unix

User Rating:  / 15

Random read / write speed

Operating systems issue many small, random I/O operations. This is even more true when you put many OS onto one single physical server. In this case, random I/O speed become a crucial parameter. 

Please note that the following IOMeter results were taken with cache=none only, as a writeback cache would unrealistically distort the results.

How BTRFS fares here?

BTRFS random speed

 Random read speed is very good, even better then EXT4.

However, random write are an entirely different matter: default BTRFS performances are 6x lower then EXT4! While disabling CoW and preallocating all disk blocks give quite an improvement, it remain very slow. As a side note, see how EXT4 preallocated score is way lower than not-preallocated one: it depend on EXT4 excellent sparse-file support.


#1 CSRedRat 2013-11-13 16:32
Btrfs is great!

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