Re: btrfs subvolume snapshot performance problem

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 [off-list ref] wrote:

quoted

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.