Question
Huge number of TCP segment retransmissions
I have encountered network issues (documents are printing multiple time by chance) while cups printing from a Digitalocean server (CentOS) to a external printer. Doing a network analysis with Wireshark I saw that by chance packages are retransmitted to the print server and so documents are printed 2 or 3 times.
I have a server at an other cloud provider and with that I don’t have that problems.
A netstat -s for the digital ocean server shows:
netstat -s | grep retr
650374 segments retransmited
1 times recovered from packet loss due to fast retransmit
1 timeouts after reno fast retransmit
44015 fast retransmits
5833 forward retransmits
4373 retransmits in slow start
1 classic Reno fast retransmits failed
1428 SACK retransmits failed
For the other cloud provider it shows
netstat -s | grep retr
8389033 segments retransmited
73 times recovered from packet loss due to fast retransmit
16 timeouts after reno fast retransmit
54023 fast retransmits
3285 forward retransmits
8724 retransmits in slow start
37 classic Reno fast retransmits failed
1732 SACK retransmits failed
The number of retransmissions on the digitalocean server is significant higher than on the other cloud server from a other cloud provider - although the other cloud server has much more load and much more network traffic.
Does anyone have an idea what could be the reason for that?
Thanks for any help.