Hi,
I do have one fileserver, which is compared to other systems slow when transferring file through the lan.
The test I did get a transfer speed of about 70 - 80 MB/s. I copy files by rsync or scp from a SSD disk to the servers ISCSI Storage and I tested to copy to a serverside RAM disk.
I copy one big file of about 2/10 GB; 2 is to the RAM disk.
The point is, the mentioned one server just get rates off 35+- MB :/ To DAS HW Raid and RAM disk.
And I don't have any clue, why it is so slow ....
All servers and clients are connected to gbit full duplex cisco switche ports, which are configured the same. The servers ar centos 6.3. Filesystems ext4 with default settings.
I checked cables and logfiles but don't get any errors/warnings to.
The difference is: The concerned server has a 'small' CPU: Intel(R) Xeon(R) CPU 3040 @ 1.86GHz Dual Core.
My question: What can affect the network speed? What parameters can I check?
Thanks for any suggestion or hints! Best Regards . Götz
On 08/21/2012 08:54 AM, Götz Reinicke wrote:
The test I did get a transfer speed of about 70 - 80 MB/s. I copy files by rsync or scp from a SSD disk to the servers ISCSI Storage and I tested to copy to a serverside RAM disk.
What does "top" say on the server when you're copying?
Mogens
Am 21.08.12 09:14, schrieb Mogens Kjaer:
On 08/21/2012 08:54 AM, Götz Reinicke wrote:
The test I did get a transfer speed of about 70 - 80 MB/s. I copy files by rsync or scp from a SSD disk to the servers ISCSI Storage and I tested to copy to a serverside RAM disk.
What does "top" say on the server when you're copying?
load average: 0.75, 0.23, 0.07
Cpu(s): 56.8%us, 12.1%sy, 0.0%ni, 19.0%id, 8.6%wa, 0.3%hi, 3.1%si, 0.0%st
564 root 20 0 98.5m 6872 2968 R 99.0 0.2 1:08.10 sshd 569 root 20 0 105m 860 360 R 35.2 0.0 0:22.33 rsync
/Götz
On 08/21/2012 09:30 AM, Götz Reinicke wrote:
564 root 20 0 98.5m 6872 2968 R 99.0 0.2 1:08.10 sshd
It looks like ssh is the rate limiting step in your rsync.
What cipher are you using for ssh?
I use
rsync --rsh='/usr/bin/ssh -c arcfour128' ...
that helps quite a bit on my hardware, your hardware might do better with another cipher.
You should check out https://bbs.archlinux.org/viewtopic.php?id=136713 to learn more about this.
Mogens
Am 21.08.12 09:37, schrieb Mogens Kjaer:
On 08/21/2012 09:30 AM, Götz Reinicke wrote:
564 root 20 0 98.5m 6872 2968 R 99.0 0.2 1:08.10 sshd
It looks like ssh is the rate limiting step in your rsync.
What cipher are you using for ssh?
I use
rsync --rsh='/usr/bin/ssh -c arcfour128' ...
that helps quite a bit on my hardware, your hardware might do better with another cipher.
You should check out https://bbs.archlinux.org/viewtopic.php?id=136713 to learn more about this.
Thanks, that shows a much different transfer speed :)
I was not thinking, that rsync also involves ssh and de/encryption speed .. so the bottleneck looks like the cpu in my test.
Thanks a lot I learned something new to me :) Regards . Götz
-
Götz Reinicke -
Mogens Kjaer