measure and monitor before you change anything
By timatworkhomeandinbetween on Sep 09, 2005
Here is something to think about...
If you are going to do a major change to a machine/application then it is worthwhile investing some time in getting some baseline measurements of the system's configuration/performance before you change anything. Exactly what is worth gathering depends on the machine but I see many escalations where we are forced to explain why after a major change the system appears to be slow but with no possibility to gather any data from before the changes.
An example of this is a customer moving to 64 bit oracle who suffers much slower i/o performance, luckily there are some snippets of sar data from before the change that allowed us to spot that the amount of i/o had greatly increased due to changes in the Oracle configuration
prepare for the worst and it won't happen.