Joshua Harlow wrote:
After reading over the following interesting article about redis and
redlock (IMHO it's good overview of distributed locking in general):
http://martin.kleppmann.com/2016/02/08/how-to-do-distributed-locking.html#protecting-a-resource-with-a-lock
(I personally recommend people read the whole article as well, as it's
rather interesting, as well as the response from the redis author at
http://antirez.com/news/101).
It got me wondering if with all the locking and such that is getting
used in openstack (distributed or not) that as we move to more
distributed locking mechanisms (for scale reasons, HA, active-active...)
that we might need to have a way to fence modifications of a storage
entry (say belonging to a resource, ie a volume, a network...) with a
token (or sequence-id) so that the problems mentioned in that blog do
not affect openstack (apparently issues like it have affected hbase) and
the more we think about it now (vs. later) the better we will be.
Anyone have any thoughts on this?
I had the same reaction back when I read that article. That sounds like
a very useful and relatively cheap primitive to have in our DLM API.
Perhaps tooz can along with its lock API also provide a token for each
lock that can be used to interact with a storage layer (and that token
can checked by the storage layer to avoid storage layer corruption).
+1
--
Thierry Carrez (ttx)
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