qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH] qemu-img: set nocow flag to new file


From: Alex Bennée
Subject: Re: [Qemu-devel] [PATCH] qemu-img: set nocow flag to new file
Date: Thu, 14 Nov 2013 09:44:42 +0000
User-agent: mu4e 0.9.9.6pre2; emacs 24.3.1

address@hidden writes:

> Set NOCOW flag to newly created images to solve performance issues on btrfs.
>
> Btrfs has terrible performance when hosting VM images, even more when the 
> guest
> in those VM are also using btrfs as file system. One way to mitigate this bad
> performance is to turn off COW attributes on VM files (since having copy on
> write for this kind of data is not useful).
<snip>

It's been a while since I had to mess with this performance mystery but
I recall you also need to ensure the partition needs to be mounted with
the nodatacow mount option. Unless this has changed we should probably
warn the user about that.

--
Alex Bennée




reply via email to

[Prev in Thread] Current Thread [Next in Thread]