There are lots of tools for studying the systems use of CPU and memory, but I/O is generally harder to track down. A useful trick is available via the block dump. Setting the value to "1" turns on block access logging to the kernel ring-buffer [aka dmesg] and a value of "0" turns it back on. This means it can be turned on by a simple:
echo "1" > /proc/sys/vm/block_dump
This logs the accesses to the block storage as:
[ 2032.934178] postmaster(11528): READ block 5058592 on dm-3 (16 sectors)
[ 2032.934200] postmaster(11528): READ block 5058624 on dm-3 (32 sectors)
[ 2032.934240] postmaster(11528): READ block 3172800 on dm-3 (16 sectors)
[ 2032.945328] banshee-1(11267): dirtied inode 1051864 (banshee.db-journal) on dm-0
[ 2032.945336] banshee-1(11267): dirtied inode 1051864 (banshee.db-journal) on dm-0
[ 2033.042671] python(11518): READ block 9017928 on dm-2 (32 sectors)
[ 2033.055771] python(11518): dirtied inode 267260 (expatbuilder.pyc) on dm-2
[ 2033.055808] python(11518): READ block 9017960 on dm-2 (40 sectors)
[ 2033.412972] nautilus(11078): dirtied inode 410492 (dav:host=127.0.0.1,port=8080,ssl=false) on dm-0
[ 2033.413001] nautilus(11078): READ block 50855560 on dm-0 (40 sectors)
[ 2033.431011] nautilus(11078): dirtied inode 410596 (dav:host=127.0.0.1,port=8080,ssl=false-ab9de673.log) on dm-0
[ 2033.431044] nautilus(11078): READ block 50855736 on dm-0 (64 sectors)
[ 2034.221831] jbd2/dm-2-8(386): WRITE block 21261800 on dm-2 (8 sectors)
[ 2034.221887] jbd2/dm-2-8(386): WRITE block 21261808 on dm-2 (8 sectors)
Handy.
