Liebach v3.0 alpha

Disabling harddisk writecache on OpenBSD


Years ago I read about the write cache in harddisks and how it could be a threat to filesystem integrity. I were a fresh and naïve (read: stupid & ignorant) Linux user then, so I didn't know how to disable it. Then I forgot all about it until yesterday when a mail on the OpenBSD misc@ mailinglist touched upon the subject. I read atactl(8) and then added this code to the top of /etc/rc.local:

# Disable IDE harddisk writecache.
echo -n "Disabling disc hardware write cache"
drives="wd0"  # List of IDE drives in this machine.
for drv in ${drives}; do
    /sbin/atactl /dev/r${drv}c writecachedisable
echo "."

Apparently MirBSD has something like it in the standard /etc/rc script. MirBSD is based on OpenBSD, but is IA-32 only. If I had a spare machine I'd give it a try. Maybe I will anyway.

Oh! and by the way; there's a new advisory out on OpenSSL. So, expect patches from various vendors to come out RSN™.

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