Iostat list non-existing block device xvdap1 -

iostat output on system:

avg-cpu:  %user   %nice %system %iowait  %steal   %idle            0.13    0.02    0.42    0.32    0.10   99.01  device:            tps    kb_read/s    kb_wrtn/s    kb_read    kb_wrtn xvdap1            1.29        32.67        10.06   27432377    8450380 

but if examine lsblk, not find device named xvdap1:

name  maj:min rm size ro type mountpoint xvda1 202:1    0   8g  0 disk / 

moreover, xvdap1 cannot found in /dev/:

user@host:~$ ls /dev/xvd* /dev/xvda1 

i'm inclined believe xvdap1 same /dev/xvda1, why on earth have 2 different names? problem, because partitions mounted /proc/mounts , there not describe xvdap1, xvda1. , if pass /dev/xvda1 request iostat, f.e.:

iostat -p /dev/xvda1 

he nothing output.

xvdap1 is xvda1 seems weirdness how iostat displaying devicename. if run iostat -p /dev/xvda1 , iostat should see exact same numbers xvdap1 , xvda1 devices:

$ iostat -p /dev/xvda1  device:            tps    kb_read/s    kb_wrtn/s    kb_read    kb_wrtn xvda1             0.26         0.07         2.66     258713   10327556  $ iostat   device:            tps    kb_read/s    kb_wrtn/s    kb_read    kb_wrtn xvdap1            0.26         0.07         2.66     258713   10327556 xvdb              0.00         0.00         0.00        684          0 xvdf              0.77         0.10         5.43     403313   21062404 xvdg              0.00         0.00         0.00        684          0