At around 8:06 a.m. PDT, we began receiving alerts referencing one of our LDAP servers. Upon investigating, we discovered that server was non-responsive and we were unable to remotely access it. As a result, we performed a reboot of the physical server.
After the reboot, the LDAP server came back online and services returned to normal. Once services had returned to normal, our DevOps team quickly began investigating the root cause. Based on their findings, they discovered that their was a memory issue that caused the server to freeze up.
The result of the issue caused a less than 30 minute window of intermittent issues sending mail or access webmail. Users also experienced some delays in mail delivery between 8:00 a.m. and 10:00 a.m. PDT.
We are working on a few performance tuning items and additional monitoring for the LDAP server to reduce the risk of this issue occurring again.