Check HTTP Connections
The following may indicate if you’re getting slammed by one host. It should display all current connections to port 80 ordered by count
netstat -anp |awk '/:80/ {print $5}' | cut -d: -f1 | sort | uniq -c | sort -n
How to Release Memory/Caches/Buffers
To release disk buffers and caches used by the kernel, you need to be “root”. Then the following one line command can do the work:
# sync && echo 3 > /proc/sys/vm/drop_caches
First we run the sync command before dropping the cache. Doing this will ensure that all memory in the cache is updated and all dirty pages are synchronized before dropping the cache. The next step is echoing “3” to the /proc/sys/vm/drop_caches file which will signal the kernel to release the pagecache, dentries and inodes.