Is there a way to detect memory fragmentation on Linux? This is because on some long running servers I have noticed performance degradation and only after I restart process I see better performance. I noticed it more when using Linux huge page support -- are huge pages in Linux more prone to fragmentation?
I have looked at /proc/buddyinfo in particular. I want to know whether there are any better ways(not just CLI commands per se, any program or theoretical background would do) to look at it.
I have a linux database(MySQL) server(Dell 2950) with a 6-disk RAID 10. The default IO scheduler on it is CFQ. However, from what I have read and heard, there is no need for a scheduler like CFQ when reordering/scheduling is also done by underlying RAID controller; on the contrary since it does not account underlying RAID configuration into account performance may actually degrade with CFQ. The primary concern is to reduce CPU usage and improve throughput. Also, I have seen recommendations of using noop/deadline IO scheduler for databases primarily because of the nature of their R/W access.
So, the question is whether noop or deadline scheduler should be used instead of CFQ in these circumstances.