If apache is growing and growing in memory usage, and does not stablize please see the checklist below. If apache is simply using more memory, but has stablized (for example, Apache is using 100MB of memory, as opposed to 40MB of memory without modsecurity) this is normal. modsecurity caches the rules, and certain activities to speed up processing. Memory is infinitely faster than your hard drives, and loading the rules from the hard drive would be terrifyingly slow, too slow to be usable.