innodb_log_file_size parameter

[Mark Rigney]

Hi,
I posted this originally on the newbie page but I thought I might get a better response here.

This morning my db crashed due to a power outage. I was unable to restart the db and after checking the log I had the following error:

InnoDB: Error: log file .\ib_logfile0 is of different size 0 10485760 bytes
InnoDB: than specified in the .cnf file 0 104857600 bytes!
050628 10:11:48 [ERROR] Can't init databases
050628 10:11:48 [ERROR] Aborting

Prior to the db crash ( a day or 2 earlier ) I had changed the innodb_log_file_size parameter from 10M to 100M and restarted the db. To recover from the crash I changed the parameter back to 10m and that let me get past the above error and restore the db.

My question now is why was this the case? Should'nt it have adjusted after the last successful db startup? What am I missing? Furthermore, what should my process be to change back to a 100m innodb_log_file_size? Should I change the parameter and then cycle the server? What am I missing?

Thanks in advance.