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Re: Speed Problem Copying Files

On Thursday 09 May 2019 04:49:32 am Lothar Schilling wrote:

> Hi everybody,
> for years I have used CentOS for our server landscape. Now I decided
> to give Debian a try. I just set up a Stretch 9.8 system supposed to
> become our main backup server. So I set up a backup job wih rsync. But
> the going is really very very slooooow. Trying to figure out what's
> happening:
>   * iperf -c [host] => bandwith almost 1000 Mbit, that's fine.
>   * dd if=/dev/zero of=/daten/testfile bs=1G count=10 oflag=direct =>
>     10737418240 Bytes (11 GB, 10 GiB) kopiert, 40,4992 s, 265 MB/s, so
>     that's fine as well
> But whenever I try to rsync, cp or scp - whether copy files on the
> local hard disk only or over the network - speed goes down to 500
> kB/s.
> Filesystem is ext4.
> I don't have any clue about what's going on. Any kind of help would be
> appreciated, thank you!
> Lothar

This is an interesting question. I am useing mc to copy data from old 
wheezy drive to new stretch drive, both with speeds well above 
100M/second performance, but when dealing with small files, theres a 
penalty for obtaining the space to write to, and for the cleanup after, 
and its substantial. So I see speeds below 5 megs when dealing with 
spinning rust and my maildir format email corpus. Drive seek speeds and 
rotational latency will all figure into that, and its one of the reasons 
an SSD seems so much faster because they seek in a microsecond, and they 
don't have to wait until the sector passes under the heads of the drive.

Anything that will speed up that aspect of moving data will surely be 
appreciated, so I'll read carefully the responses here.

Thank you.

Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>