Re: [gentoo-user] network transfer speed

[bobwxc <bobwxc@88.com>]

在 2021/1/15 下午4:27, Raffaele BELARDI 写道:
>> -----Original Message-----
>> From: bobwxc <bobwxc@88.com>
>> Sent: Friday, January 15, 2021 08:57
>> To: gentoo-user@lists.gentoo.org
>> Subject: Re: [gentoo-user] network transfer speed
>>
>> 在 2021/1/15 下午2:56, thelma@sys-concept.com 写道:
>>> On both of my systems the network card speed is showing 1000
>>> cat /sys/class/net/enp4s0/speed   1000
>>>
>>> but when I do rsync larage file I only see about: 20 to 22MB/s On my
>>> home network I get about 110MB/s between PC's
>>>
>>> Both PC's have SSD  and the swith is Gigabit (I think).
>>> How to find a the bottleneck?
>> 1000Mbps network card's maximum theoretical speed is about 125MiB/s.
>> It only works in short distances.
> Correct but that's the line speed that you'll never reach, when you take into account Ethernet frame overhead, IP (and possibly TCP) header overhead and application ( rsync, FTP, SMB, NFS) overhead you get lower figures. In my experience 900Mbps (110MiBps) on a 1000Mbps line is more realistic for 'normal' transfers.
>
Yes, you are right. So it is just *theoretical* speed :-)

I don't know where does the file he sync from.
If you sync a file from a server in other city, for a 20 to 22MB/s speed 
is very normal. But if in home, that is not good.

And for ftp and rsync.
     ftp is better for transferring a single large file once.
     rsync is better for a long-term, incremental synchronization. The 
file verification of rsync may take a lot of time for first sync.