1. A system for maintaining data integrity, the system comprising: a monitoring appliance including: a memory; at least one sensor selected from a group comprising a temperature sensor, a humidity sensor and an airflow sensor; at least one processor coupled to the memory and the at least one sensor; a kernel-mode device driver executable by the at least one processor and configured to create a journal data model including: at least one variable definition associated with the at least one sensor, the at least one variable definition including an oldest update field and a latest update field; a doubly-linked list of variable update records storing one or more readings from the at least one sensor, each variable update record of the doubly-linked list of variable update records including a variable value that indicates a sensor reading from the at least one sensor; and at least one context record having an associated current timestamp field and a context update field pointing to a first variable update record of the doubly-linked list of variable update records, wherein the at least one variable definition is associated with a first variable, each of the doubly-linked list of variable update records is associated with the first variable, the oldest update field of the at least one variable definition points to a second variable update record of the doubly-linked list of variable update records, and the latest update field of the at least one variable definition points to a third variable update record of the doubly-linked list of variable update records.