We had a similar issue with our MySQL server farm (seven dedicated MySQL servers). Replication was very slow, falling behind for no apparent reason. We were reaching 24 hours of lag! We never had that kind of lag before. A couple of minutes at the most.
Long story short, we rebooted to 4.15.0.34 and the servers caught up replication with in minutes! References: https://forums.mysql.com/read.php?26,669517 https://askubuntu.com/questions/1080911/linux-image-4-15-0-36-reduces-rsync-over-ssh-to-10-times-less/1082322#1082322 -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1796895 Title: Kernel 4.15.0-36 network performance regression Status in linux package in Ubuntu: Incomplete Bug description: Hardware: HP DL380 Gen 7 server with Gigabit interface. Ubuntu release: 18.04.1 Since upgrading from 4.15.0-33 to 4.15.0-36, I have noticed a dramatic slowdown in TCP over IPv6. Set up: two servers, Server A in US on Ubuntu 18.04.1, Server B in Europe. Test: Sending 400MB over TCP from Server B to Server A. With 4.15.0-33 on Server A, the transfer is completed in 24 seconds, with average speed of 139 mbps. With 4.15.0-36 on Server A, the same amount of data is transferred in 369 seconds, average speed less than 9 mbps. Looking at the result from tcpdump, I see that the there is a big difference in the TCP Window size. With 3.15-0.33 the TCP window size is around 30000. But with 3.15-0.36, the window size is only 734. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1796895/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
