hi,
tail reports this on a particular file :

tail: unrecognized file system type 0x794c7630 for '/var/log/xxx.log'.
please report this to bug-coreutils@gnu.org. reverting to polling

the file system used is :

/dev/loop0 /run/archiso/sfs/airootfs squashfs ro,relatime 0 0
airootfs / overlay
rw,relatime,lowerdir=/run/archiso/sfs/airootfs,upperdir=/run/archiso/cowspace/persistent_live/x86_64/upperdir,workdir=/run/archiso/cowspace/persistent_live/x86_64/workdir
0 0

this is a live cd of archlinux build with archiso.

regards, lacsaP.