Hi,
Since gfs2 can "allow parallel allocation from different nodes
simultaneously
as the locking granularity is one lock per resource group" per section
3.2 of [1].
Could it possible to make the locking granularity also applies to R/W
IO? Then,
with the help of "sunit" and "swidth", we basically can lock a stripe,
so all nodes
can write to different stripes in parallel, so the basic IO unit is one
stripe.
Since I don't know gfs2 well, I am wondering it is possible to do it or
it doesn't
make sense at all for the idea due to some reasons. Any thoughts would be
appreciated, thanks.
I am asking the question because if people want to add the cluster
support for
md/raid5, then it is better to get the help from filesystem level to
ensure only one
node can access a stripe at a time, otherwise we have to locking a
stripe in md
layer which could cause performance issue.
[1] https://www.kernel.org/doc/ols/2007/ols2007v2-pages-253-260.pdf
Regards,
Guoqing
