[Dovecot] dsync is SLOW compared to rsync

[Jeff Gustafson]

On Fri, 2012-03-23 at 23:12 -0700, Linda Walsh wrote:

> Next -- bench "cp -ax", against rsync -axHAX when it has to copy >75% of 
> the data (cp ~6-8x speed).  But for file speed, 'dd' is king, as it can 
> use large buffers (~16MB gives best results on my local Gbit network), 
> but it
> misses all those pesky acls and extended attrs, not to mention file 
> perms...*sigh*   Compare that to the I/O done 4k at a time by many older 
> utils...

cp -ax:
real	0m3.088s
user	0m0.034s
sys	0m3.054s

rsync -axHAX
real	0m15.850s
user	0m19.314s
sys	0m8.816s

	dsync's time was over six minutes. Each time I cleared out the
destination folder. dsync is doing something that is taking much, much,
much longer to do.

	...Jeff