$pkg info | grep samba samba36-3.6.25_3 Free SMB and CIFS client and server for Unix When accessing a samba server from MacOSX 10.10.5 w/ aio enabled via the following in the global section: aio read size = 1 aio write size = 1 aio write behind = true I get tons of errors: [2016/06/25 13:07:16.538032, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.542241, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.543268, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.545097, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.651903, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.654807, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.673397, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.686022, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.744821, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.812774, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.839417, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.875530, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.877068, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.905727, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.906400, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.918365, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.919426, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.919999, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.953497, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported [2016/06/25 13:07:16.965503, 0] smbd/aio.c:232(schedule_aio_read_and_X) schedule_aio_read_and_X: aio_read failed. Error Operation not supported and so on... This significantly impacts performance as Samba now consumes a large amount of CPU time, I believe trying the aio call multiple times, before it gives up, and tries a normal read or write.. After disabling this, CPU usage dropped from 60-90% down to ~5%... There are many people who have aio turned on in their configs as this is a recommended performance tuning option for Samba posted throughout the inet.
You can set sysctl vfs.aio.enable_unsafe=1 to make aio behave much like kldload aio used to do: read/write requests to regular files are done by AIO daemons and cannot be aborted.
net/samba36 expired and is removed from the tree: https://svnweb.freebsd.org/ports?view=revision&revision=415323 Can we close this issue? Or does this problem affect newer versions of Samba as well?