[zfs-discuss] sending stream too slow on busy system

David Bruzos dbruzos at succinctsystems.com
Mon May 23 18:06:05 EDT 2016


It does not appear that additional buffering would help much in my particular situation, but I will check it out anyway.

Thanks.


On Mon, May 23, 2016 at 03:38:32PM -0400, ZFS Discuss ML wrote:
> Have a look at mbuffer. I've used it and it seems to speed up replication
> considerably
> 
> 
> On Mon, May 23, 2016 at 2:54 PM, Paul Dagnelie via zfs-discuss <
> zfs-discuss at list.zfsonlinux.org> wrote:
> 
> > First, what version are you running?  zfs send has been going through some
> > changes lately, and the tunables are changing with it.  Second, you
> > probably want to look into resumable send/recv; if your send is going to
> > take a week, you don't want to have to restart on day 6 because your
> > network dropped some packets on the floor.
> >
> > On Sun, May 22, 2016 at 5:29 PM, David Bruzos via zfs-discuss <
> > zfs-discuss at list.zfsonlinux.org> wrote:
> >
> >> Hello all:
> >> I have a reasonably busy system that I need to stream about a TB of data
> >> from in order to migrate some virtual machines to a remote site, but the
> >> zfs send is really slow.  A similar machine with no VMs running seems to
> >> send about 10-15 times faster than the busy box.
> >> My plan is to do an initial send and then a final incremental send, in
> >> order to cut the down time to a minimum, but at this rate, it will take me
> >> a week to complete the initial send.  Of course, something is likely to go
> >> wrong during this long time, so I'll have to start over.
> >>
> >> What are some tunable parameters that can increase ZFS streaming
> >> performance that I can play with while the system is up and running and are
> >> not likely to cause some kind a nasty crash and/or sideaffect?
> >>
> >> Thanks!
> >>
> >> David
> >>
> >> _______________________________________________
> >> zfs-discuss mailing list
> >> zfs-discuss at list.zfsonlinux.org
> >> http://list.zfsonlinux.org/cgi-bin/mailman/listinfo/zfs-discuss
> >>
> >
> >
> >
> > --
> > Paul Dagnelie
> >
> > _______________________________________________
> > zfs-discuss mailing list
> > zfs-discuss at list.zfsonlinux.org
> > http://list.zfsonlinux.org/cgi-bin/mailman/listinfo/zfs-discuss
> >
> >

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