[j-nsp] disaccord in output of "df" and "df <mount-point>" in Junos

[Martin T]

Hi,

when I execute "df" in SRX240H2(Junos 12.3X48-D30.7), then I can see
following mount-points:


$ df
Filesystem   512-blocks    Used  Avail Capacity  Mounted on
/dev/da0s2a     1264552  363576 799812    31%    /
devfs                 2       2      0   100%    /dev
/dev/md0          40024   12624  24200    34%    /junos
/cf/packages    1264552  363576 799812    31%    /junos/cf/packages
devfs                 2       2      0   100%    /junos/cf/dev
/dev/md1        1063984 1063984      0   100%    /junos
/cf               40024   12624  24200    34%    /junos/cf
devfs                 2       2      0   100%    /junos/dev/
/cf/packages    1264552  363576 799812    31%    /junos/cf/packages1
procfs                8       8      0   100%    /proc
/dev/bo0s3e       94304     228  86532     0%    /config
/dev/bo0s3f     1264808  844256 319368    73%    /cf/var
/dev/md2         687744   46788 585940     7%    /mfs
/cf/var/jail    1264808  844256 319368    73%    /jail/var
/cf/var/log     1264808  844256 319368    73%    /jail/var/log
devfs                 2       2      0   100%    /jail/dev
/dev/md3         128728       8 118424     0%    /mfs/var/run/utm
/dev/md4           3768       8   3460     0%    /jail/mfs
$



As seen above, none of the mount-points matches /var/log. Now when I
execute "df /var/log", then I expect it to be on /(and thus on
/dev/da0s2a file-system), but for some odd reason it seems to be
associated with /cf/var(and thus on /dev/bo0s3f file-system):


$ df /var/log
Filesystem  512-blocks   Used  Avail Capacity  Mounted on
/dev/bo0s3f    1264808 844616 319008    73%    /cf/var
$


Or another example where output of "df" and "df <mount-point>" do not match:

$ df /usr
Filesystem 512-blocks    Used Avail Capacity  Mounted on
/dev/md1      1063984 1063984     0   100%    /junos
$


What causes Junos(or underlying FreeBSD) to behave like that?


thanks,
Martin