Comrades,
Ceph's victory is assured. It will be the storage system of The Future.
Matt Benjamin has reminded me that if we don't act fast¹ Ceph will be
responsible for destroying the world.
utime_t() uses a 32-bit second count internally. This isn't great, but it's
something we can fix. ceph::real_time currently uses a 64-bit bit count of
nanoseconds, which is better. And we can change it to something else without
having to rewrite much other code.
The problem lies in our encode/deocde functions for time (both utime_t
and ceph::real_time, since I didn't want to break compatibility.) we
use a 32-bit second count. I would like to change the wire and disk
representation to a 64-bit second count and a 32-bit nanosecond count.
Would there be resistance to a project to do this? I don't know if a
FEATURE bit would help. A FEATURE bit to toggle the width of the second
count would be ideal if it would work. Otherwise it looks like the best
way to do this would be to find all the structures currently ::encoded
that hold time values, bump the version number and have an 'old_utime'
that we use for everything pre-change.
Thank you!
¹ Within the next twenty-three years. But that's not really a long time in the
larger scheme of things.
--
Senior Software Engineer Red Hat Storage, Ann Arbor, MI, US
IRC: Aemerson@{RedHat, OFTC, Freenode}
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