iSCSI speed drop

Question

Computer networks

Hi all.

We have: ubuntu server on which iscsi target is configured, + kvm on which 2 virtual machines (web server and minecraft server) are spinning, the network for everyone is organized by a bridge and tied to a gigabit network card.

I noticed that the linear speed of access to the iscsi target does not rise above 25 MB / s, while through samba it is stable around 60 MB / s, and even earlier the speed via iscsi was about a hundred.
I don’t know which way to dig, is it possible because of the bridge?

Answer 1

Apparently the problem was in the network bridge, I solved it by installing a second network card and moving iscsi target to it.

Answer 2

Worth monitoring.
Network performance:
iperf
Network and disk subsystem load:
dstat
iostat

Answer 3

> I noticed that if I reconfigure /etc/network/interfaces and reboot the system, the speed temporarily rises (several hours).
Again, try iperf. Plus, it will be useful to look at dmesg/messages/syslog.