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Re: [LUG] (g)rsync stalling

 

On 16/04/17 14:51, Tom via list wrote:
> I've been using grsync to backup my laptop to another Ubuntu server with
> the storage exported via samba and is taken to stalling after a couple
> of hours. If I whip out the shared drive (usb) and pop it directly into
> the laptop is works OK. I cant seem to find any errors on either machine
> that would explain the halting.
> 
> My ~ directory tree has 2.5Million files and around 200G but the server
> seems not to have memory problems.
> 
> Any ideas where to look ?
> 
> Tom te tom te tom

Could be a lot of things but your first job is going to be triaging the
problem with some more details. OS types and versions, kernel+samba
revisions, etc are all important.

I tried using grsync randomly just a few days ago whilst doing a *huge*
backup of pretty much my entire local data store offsite and it crashed
out fast once and then hung nearly as quickly 5 minutes later. I apt-get
scornfully-purged it and went back to good old rsync (I only wanted a
pretty progress bar to look at after all) which proceeded to crunch
through all 12Tb or so without a single glitch. So the very first thing
to do would be to repeat the backup again but with rsync instead of
grsync which I personally found buggy and useless on Ubuntu.

Hopefully it's just that because the next steps are complicated and
you're going to have to start digging pretty deep into system internals
otherwise. Ubuntu doesn't have a good history when it comes to sysctl
tuning and there are many, many online bugs relating to slow, stalling
or completely unusable USB transfers.

What does this get you (on both machines)?

cat /proc/vmstat | egrep "dirty|writeback"

Cheers
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