Re: btrfs subvolume snapshot performance problem

[Sander <sander@humilis.net>]

Sylvain Alain wrote (ao):
> gentootux ~ # mount /dev/sda4 -o
> noatime,ssd,discard,compress=lzo,noacl,space_cache,subvolid=0
              ^^^^^^^

> Instead of 3 secondes to run the snapshot, it took almost 4 minutes.

Let me repeat the answer cwillu gave to Russell on this, and Russell's
response:

Russell Coker wrote (ao):
> On Sun, 16 Dec 2012, cwillu <cwillu@cwillu.com> wrote:
> > Don't use discard; it's a non-queuing command, which means your
> > performance will suck unless your device is really terrible at
> > garbage collection (in which case, it's just the lesser of two evils).
> 
> Thanks for the advice. On one of my systems a reinstall of the linux-
> image-3.6-trunk-amd64 package went from almost 4 minutes to only 29
> seconds when I removed the discard option.