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Showing posts from September, 2012

SysAdmin 101: Typical Power related symptoms - or TG4s Leinstergate for Dummies

If you are a sysadmin, and probably on call for at least some nights and weekends, one thing you need to learn very fast is about data centre problems, hardware problems and typical patterns.

Basically power and network problems have very similar symptoms.  If you've got a multi-level service or application that maybe consists of a database sitting on a Linux or Unix cluster, served out by a Windows cluster based application, all of it sitting on shared storage, you'll see typical alert patterns.

Power:
When power fails, you generally notice two things - everybody, everything loses access.  Applications elsewhere that depend on this or monitor it go ballistic.  Network alerts indicate loss of link.  This is important for the next type of alert.  Users cannot access the application, but this often is secondary to the fact that they are scrambling with their powered down PCs in the dark anyway.  Some data centres may go into generator modes as secondary power kicks in.  With th…