zfs send/receive: is this slow?

[Artem Belevich]

On Wed, Sep 29, 2010 at 11:04 AM, Dan Langille <dan at langille.org> wrote:
> It's taken about 15 hours to copy 800GB.  I'm sure there's some tuning I
> can do.
>
> The system is now running:
>
> # zfs send storage/bacula at transfer | zfs receive storage/compressed/bacula

Try piping zfs data through mbuffer (misc/mbuffer in ports). I've
found that it does help a lot to smooth out data flow and increase
send/receive throughput even when send/receive happens on the same
host. Run it with a buffer large enough to accommodate few seconds
worth of write throughput for your target disks.

Here's an example:
http://blogs.everycity.co.uk/alasdair/2010/07/using-mbuffer-to-speed-up-slow-zfs-send-zfs-receive/

--Artem