Just finished up a quick two minutevideo presented by my colleague, Jim Bahn, on how to solve the common problemof SAN oversubscription ratio problems. Interestingly I've found theoversubscription problem with just about every end user I've been to this lastyear, so there clearly is a lack of awareness on the issue.

The biggest limitation is that youcannot historically trend the ASIC or Blade utilisation of a SAN Director withits native tools. I've sadly had customers that have had oversubscriptionissues at different times of the day on different Blades and ASICs e.g. nightlybackups etc. One customer had a six month problem with their Oracle backups andwhen we deployed the VirtualWisdom software we found that this was due to theoversubscription. Every other night the backups were causing the Blades tomomentarily have link resets which in turn would reset each of their tapedrives causing 'shoe-shining' and the prolonged backups. There was no way wecould have identified this without the historically trending feature unless wephysically saw this happen on the switches at the exact moment itoccurred.
This is just one of many examples ofproblems that occur due to incorrect oversubscription.
Anyhow enough of the anecdotes here's the video:
