We have an exchange 2013 DAG with 2 sites and 4 servers. Each server contains 4 databases. One database is active on each server and 3 are passive (each server contains a copy of all 4 databases)
Periodically (maybe 2-3 times per week) there will be an unexpected network spike where two servers (between sites) will exchange data at our site-to-site link speed (50mbps) for about 15 minutes. During this time there is severe performance degradation (in outlook for users on those servers and on the network due to the link saturation)
My question is two-fold:
- What causes this large exchange of data between the servers?
- Is there a way to prevent it from happening or cause it to not saturate the link without implementing QoS on the link?
Thanks!