[kwlug-disc] rsync causing processor spike

unsolicited unsolicited at swiz.ca
Fri Dec 6 16:08:05 EST 2013

Is it 'momentary' while it figures out its filelist to be copied?

iotop (htop/atop/top) reveal anything useful?

Can you give us the path to external backup? e.g. I regularly mount a 
windows share and rsync to it, at /mnt/machine/share and don't see what 
you're experiencing. i.e. As it's not an rsync: form of destination, 
rsync thinks everything is local and does not calculate checksums. I 
suspect the same is true for you. (i.e. No great whack of cpu 
consumption in checksum calculations going on - the issue lies 
elsewhere. I suspect.)

Any chance the logs reveal it's going down a (expensive) symbolic link 

What's the filesystem on the external drive?

USB? (3?)

What speed CPU / memory?

There is a --bwlimit parameter, if that's useful.

Reasonable amount of freespace available?

I have seen what you talk about, but it's been swap going stupid causing 
it. (swapoff -a && swapon -a &) being recommended IIRC, in those cases. 
swapon -s reveal anything unexpected?

On 13-12-06 11:43 AM, Joe Wennechuk wrote:
> I am trying to rsync to an external drive on a running system;
> however, it is causing the processor to spike and bring down the
> webserver. I tried#> ionice -c3 -n19 rsync -vhr /dir/*
> /external/backup/ but it still spikes the processor?

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