There is effectively no limit on context lease but it is vital to take lease time into consideration when sizing a Context Store deployment as this can drastically change the amount RAM required in the cluster to store the context data for such a long time.

The default lease time is 2 hours (7200 seconds) and the maximum lease time threshold (above which a warning will be logged but request will not be blocked) is 4 hours (14400 seconds).

Both of these figures can be set anywhere within the range specified in the Context Store documentation. As per the description of lease parameter in the Avaya Context Store Developer Guide, The valid lease must be in the range 1 to 2147483647. (2147483647 is the maximum value permitted for an integer field such as this.)

In the Capacity Planner tool, configuration sizing options are offered for up to 90 hours or days (though if you're storing data for 90 days, what you need is a database and not Context Store!)