I am mixing 1Gbit with 100Mbit lan. Is it a bad idea?

[Anton Aleksandrov]

Hello.
We are running cluster (5.0.7) on 8 data nodes and 3 API nodes. When we set it up some time ago we had 100Mbit switch between them and as iptraf showed - all 100Mbit were used when selecting data and about 20-30Mbit - when inserting data from sql files. That's why we upgraded switch to 1Gbit, but some of network boxes (at API nodes, I am sure, may be one more dbnode) does not have 1Gbit, so they are at 100Mbit. But we have noticed drammatical decrease in speed, especially when inserting data from sql file - speed does not come higher than 5-6Mbit.. And suddenly I have discovered this page: http://dev.mysql.com/doc/mysql/en/multi-computer.html which is saying "use 100mbit or 1gbit on all cluster boxes". Please tell me - is it really so bad? and why?

Thank you very much!