[Borgbackup] Slow backup speed

[Tomasz Melcer]

On 30.10.2018 18:59, Zack Coffey wrote:
> I think you are right, it's not a bandwidth issue. But NFS dealing with 
> that many small functions may be the bottleneck.

This might be a latency issue, which could be hidden by running multiple 
I/O operations at the same time. Let say, scanning multiple directories 
in many threads.

A quick test for this hypothesis would be comparing the time of two 
concurrent `find` commands to the time of a single `find` command doing 
the same. E.g.:

echo 3 >/proc/sys/vm/drop_caches && time find dirA dirB -mount -uid 999

vs.

echo 3 >/proc/sys/vm/drop_caches && time (find dirA -mount -uid 9999 & 
find dirB -mount -uid 9999 & wait)

where `dirA` and `dirB` are two directories on that NFS. I tested this 
on a local HDD (the latter 4x slower, obviously) and on CIFS/samba (the 
latter ~20% faster).


-- 
Tomasz Melcer