A number of other caches, cache divisions, and queues also exist within ZFS. Higher associative caches usually employ content-addressable memory. The MKDE caches data in memory to facilitate performance. On CPUs with small L2 caches, copying memory can be expensive operations. It also caches much of the content that it indexes. This makes incendiary grenades useful for destroying weapons caches, artillery, and vehicles. HTTP defines three basic mechanisms for controlling caches&colon; freshness, validation, and invalidation. Similar to caches, TLBs may have multiple levels. Memory for the location of caches can last up to 28 days. These contain several nest chambers, food caches, and debris piles. The Coalition had conducted around 20 airstrikes targeting weapons caches and command posts. Lunev was personally looking for hiding places for weapons caches in the Shenandoah Valley area. Other structures included kill sites, food caches, and tent encampments. This is most problematic for caches that have low associativity. The advantage of exclusive caches is that they store more data.