Re: [gentoo-user] network transfer speed

[Jack]

On 1/15/21 11:51 AM, thelma@×××××××××××.com wrote:
> On 1/15/21 2:58 AM, Michael wrote:
>> On Friday, 15 January 2021 08:42:16 GMT bobwxc wrote:
>>> 在 2021/1/15 下午4:27, Raffaele BELARDI 写道:
>>>>> -----Original Message-----
>>>>> From: bobwxc <bobwxc@××.com>
>>>>> Sent: Friday, January 15, 2021 08:57
>>>>> To: gentoo-user@l.g.o
>>>>> Subject: Re: [gentoo-user] network transfer speed
>>>>>
>>>>> 在 2021/1/15 下午2:56, thelma@×××××××××××.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.
>> There is a theoretical network speed as already mentioned.  There is a
>> protocol speed, which may limit throughput if it has e.g. heavy encryption/
>> compression and the CPU is anaemic.  Finally, there is a MoBo bus (SCSI/SATA/
>> USB) and the media storage limit.  If using USB 1.1 or 2.0 and/or the disks
>> are slow or experience write amplification, you'll find this will constrain
>> the final transfer speed significantly.
> The computers on this network are 2-meters apart and they both use SSD Drive (so USB limitation doesn't come under consideration).
> Like I said, on my home network when I transfer the 24GB file I get about 110MiBps transfer, so I was expecting the same in remote location).
> Some units are connected to a router Ausus RT-AC66U B1 but these ports are gigabit too.
When you say the computers are remote, is it possible the file is 
passing through your local computer on the way between the two remote 
machines?  Where are you actually running the rsync command?