Hello,
We are currently playing with swift and try to find out if it would be
useful for our needs. We would use the latest mitaka release. It would
be a multi-region deployment in around 4-5 different countries/DCs with
a total size of 5 TB and millions of small files. Worst case RTT between
two locations would be 400ms. I came across some questions I want to ask.
1) As far as I understood Swift returns a 200 OK if the majority of
replicas are written. Is it possible to change this ratio?
2) Does the write affinity now includes containers and accounts? Saw a
presentation from the Symantic guys on the Openstack summit where this
topic came up. And the acces time spikes if this information are
transferred from the WAN.
2a) If not does it make sense to do some kind of warm up and get the
container and account information saved in memcache for faster access?
Anybody experience at this approach?
3) Lets say we have 5 regions and a replication factor of 3. When we use
write affinity 12 copies would be written in a local cluster and then in
the background replicated to the other regions? Isn't there a better way
and avoid unnecessary local writes if they would be transferred away anyway?
4) What will happen if the WAN connection to a DC fails is there an
option to not create a another replication in other DCs just because the
WAN is of fore some minutes?
5) In a Swift multi region deployment is it possible to have local
Keystone services in every region/DC or does all authentication need to
come from the same keytone machine?
Any help and ideas appreciated!
Cheers
Chris