When investigating slow application response times, we noticed high I/O wait on one of the disks. Subsequent investigation with filemon showed /etc/filesystems as busiest in terms of number of opens and reads.

QUESTION: is it 'normal' that this file is read that often? Or is there something wrong with the file? Could opening and reading the file this many times have an adverse affect on applications?

NOTE: filemon (this is on AIX) ran for about 3688 seconds, so about an hour.



Detailed File Stats
FILE: /etc/filesystems volume: /dev/hd4 inode: 2423
opens: 290500
total bytes xfrd: 3105280481
reads: 758125 (0 errs)
read sizes (bytes): avg 4096.0 min 4096 max 4096 sdev 0.0
read times (msec): avg 0.003 min 0.001 max 11.229 sdev 0.019
writes: 1 (0 errs)
write sizes (bytes): avg 481.0 min 481 max 481 sdev 0.0
write times (msec): avg 0.004 min 0.004 max 0.004 sdev 0.000