Investigating a bit more a device reset will also trigger the
change so after changing the value you can use camcontrol reset
to trigger the change to apply using e.g.
camcontrol reset 0:0:0
While this is stated in the man for ada its not obvious that
changing the sysctl without a reset won't work, so you might
want to raise a PR about it.
Regards
Steve
----- Original Message -----
From: "Steven Hartland"
Looking at the cam ata code I can't see how those values would do
anything after booting.
I suspect they should be loader only tunables with the current code
and cant be changed on the fly for a disk that's already been
registered.
Try setting the values in /boot/loader.conf if you haven't already?
You can check the actual status of the disk itself using:-
camcontrol identify ada0
Regards
Steve
----- Original Message -----
From: "Wojciech Puchar"
after reading quite recent topics about disabling/enabling write cache, i
tried to test in on desktop 3.5" drive
kern.cam.ada.write_cache: 1
kern.cam.ada.read_ahead: 1
kern.cam.ada.0.read_ahead: -1
kern.cam.ada.0.write_cache: -1
i tried writing 1 or 0 to kern.cam.ada.0.write_cache, and there were
exactly no differences at all, and disk seems to do always write caching.
Does that drive lie and ignore commands or i do it wrong?
this is my disk.
ada0 at ahcich0 bus 0 scbus0 target 0 lun 0
ada0: <SAMSUNG HD501LJ CR100-10> ATA-8 SATA 2.x device
ada0: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 8192bytes)
ada0: Command Queueing enabled
ada0: 476940MB (976773168 512 byte sectors: 16H 63S/T 16383C)
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