What I meant was it is not supposed to store whole lot of time series data (arrays) to that file (as you would store it to your native AB data base). By words of AmiBroker it was not designed to store e.g. gigabytes of data (in the past some people already did so) -> see hard disk limits. Also you should take care since a simple StaticVarRemove("*"); (or similar var name) call in some other AFL may remove your persistent vars too (on exit or if using StaticVarAutoSave of SetOption()).
Depending on data you might rather consider using AddToComposite() (also see Foreign/SetForeign functions for calling) or SQL or ....