I am running mongodb on ubuntu server. The server time is
root# date
Thu Sep 13 21:15:58 BST 2012
But when I run the following command I get a different result
root# mongo
MongoDB shell version: 2.2.0
connecting to: test
> new Date()
ISODate("2012-09-13T20:15:58.670Z")
There is exactly one hour difference. When I update a documents updated_on field with php using MongoDate(), the value of the field is still 1 hour off.
[EDIT]
Actually I just checked my php error log and the time in the log file is 1 hour off as well
[13-Sep-2012 20:11:14 UTC] Log Message (Time should be 21:11:14)
Mongo tells you
Z = Zulu time / Zero offset / UTC. You can also express the time in that TZ as 2012-09-13T20:15:58.670+00:00, as defined in the ISO8601 standard by the way.
BST is UTC+1. So, they are the same time but in different time zones.