The performance impact of LVM snapshot

gistfile1.txt

rainux@kerrigan ~
% YUKI.N> bonnie++
Writing with putc()...done
Writing intelligently...done
Rewriting...done
Reading with getc()...done
Reading intelligently...done
start 'em...done...done...done...
Create files in sequential order...done.
Stat files in sequential order...done.
Delete files in sequential order...done.
Create files in random order...done.
Stat files in random order...done.
Delete files in random order...done.
Version 1.03e       ------Sequential Output------ --Sequential Input- --Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
kerrigan        16G 92853  92 95206  22 36664  11 87646  84 75233  10 219.1   1
                    ------Sequential Create------ --------Random Create--------
                    -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
kerrigan,16G,92853,92,95206,22,36664,11,87646,84,75233,10,219.1,1,16,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++
rainux@kerrigan ~
# YUKI.N> sudo lvcreate -C y -L 120G -s -n home_snapshot /dev/swarm/home
  Logical volume "home_snapshot" created
rainux@kerrigan ~
% YUKI.N> bonnie++
Writing with putc()...done
Writing intelligently...done
Rewriting...done
Reading with getc()...done
Reading intelligently...done
start 'em...done...done...done...
Create files in sequential order...done.
Stat files in sequential order...done.
Delete files in sequential order...done.
Create files in random order...done.
Stat files in random order...done.
Delete files in random order...done.
Version 1.03e       ------Sequential Output------ --Sequential Input- --Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
kerrigan        16G 23901  36 23508   4 37656  15 89257  86 121028  30 278.2   2
                    ------Sequential Create------ --------Random Create--------
                    -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
kerrigan,16G,23901,36,23508,4,37656,15,89257,86,121028,30,278.2,2,16,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++