1. A method, comprising: identifying a cache window to be flushed from a cache, wherein the cache includes a plurality of cache storage devices; determining whether at least one cache storage device of the plurality of cache storage devices is in a critical condition, wherein a particular cache storage device is determined to be in the critical condition when a free physical space available on that particular cache storage device is below a threshold and an exposed logical space of the particular cache storage is greater than the free physical space available on that particular cache storage device; determining whether the cache window to be flushed resides on said at least one cache storage device in the critical condition; flushing the cache window from the cache when the cache window resides on said at least one cache storage device in the critical condition; and postponing flushing of the cache window when the cache window does not reside on said at least one cache storage device in the critical condition.