How to disable hard disk write cache?

Xu Zhe xzpeter at
Tue Sep 16 09:37:14 UTC 2014

Hi, all,

Does anyone knows how to disable write cache of hard disk?

I have found some hints here at Freebsd website:

However, this seems only work for ATA devices, what about SAS/NLSAS devices
(Meanwhile, it seems that there is no such sysctl in latest Freebsd release,
which is 10.0)?

Any hints are welcomed!

Thanks in advance.

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