Is it safe to run gjournal on aac-based system (BIO_FLUSH)?
toomas.aas at raad.tartu.ee
Tue Sep 14 18:32:44 UTC 2010
I'm planning to install FreeBSD 8.1 on a system which has Adaptec
4805SAS RAID controller (using aac driver). I'd like to use gjournal
for the data partition, but I have some doubts regarding the (lack of)
I have another system with FreeBSD 7.3 and a different aac-based
controller where I've been using gjournal for 3 years. Every time the
system boots, it prints this warning:
GEOM_JOURNAL: BIO_FLUSH not supported by aacd1s2.
I understand that lack of BIO_FLUSH support means that data cannot be
safely flushed to disk and that might cause corruption in case of
sudden power loss. Is that correct? Anyway, since this system has
battery-backed write cache, I'm not too worried.
But on the system where I'm about to install now, the controller
doesn't have a battery for its cache. Hence my question - does the aac
driver on FreeBSD 8.1 still not support BIO_FLUSH? If so, I should
probably avoid using gmirror on this system?
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