From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from magic.merlins.org ([209.81.13.136]:35235 "EHLO mail1.merlins.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752115AbbEKVoR (ORCPT ); Mon, 11 May 2015 17:44:17 -0400 Date: Mon, 11 May 2015 14:44:12 -0700 From: Marc MERLIN To: Filipe David Manana Cc: "linux-btrfs@vger.kernel.org" , Filipe David Borba Manana Message-ID: <20150511214412.GE15670@merlins.org> References: <20140908015124.GA21441@merlins.org> <20140915001836.GU8530@merlins.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20140915001836.GU8530@merlins.org> Subject: Re: btrfs differential receive has become excrutiatingly slow on one machine Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Sun, Sep 14, 2014 at 05:18:36PM -0700, Marc MERLIN wrote: > On Mon, Sep 08, 2014 at 10:49:01PM +0100, Filipe David Manana wrote: > > Hi Marc, > > > > Does the sum of all reads from the stream file (fd 3) gets anywhere > > close to the total btrfs receive time? (or even more than 50%) > > Can you paste somewhere the full output of strace (with -T option)? > > Sorry for the lack of answer, I lost the snapshot I used for that mail, > so it was not possible to do again easily. > Because my backups were so hopelessly behind, I did a full resync of > /var, i.e. not a differential send (300GB or so). The copy went at about > 25GB/h, which wasn't bad at all since was over wifi (took about 14H). Sigh, now that I'm resyncing my laptop I just rebuilt after the btrfs crash, to my server (both running 3.19.5+), full btrfs sends (i.e. not incremental), are taking ages. I'm seeing less than 100GB/day on my home network when my tcp connections over wifi easily get 50MB/s Right now I'm seeing the equivalent of aout 1MB/s, or 50 times less than what my network connection can do. Last time I tried to strace btrfs send, it killed the process with SIGPIPE and I lost a full day of sync and had to start over :( It's a broad question, but how can I diagnose btrfs send being so slow without taking the risk of killing my connection? (if there is no good answer on this one, I can try another sync later with -vvv and strace if you'd like) Thanks, Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/ | PGP 1024R/763BE901