[Openstack] Swift questions

Marcus White roastedseaweed.k at gmail.com
Wed Aug 27 12:04:10 UTC 2014

Some questions on new and old features of Swift. Any help would be
great:) Some are very basic, sorry!

1. Does Swift write two copies and then return back to the client in
the 3 replica case, with third in the background?

2. This again is a stupid question, but eventually consistent for an
object is a bit confusing, unless it is updated. If it is created, it
is either there or not and you cannot update the data within the
object. Maybe a POST can change the metadata? Or the container listing
shows its there but the actual object never got there? Those are the
only cases I can think of.

3. Once an object has been written, when and how is the container
listing, number of bytes, account listing (if new container created)
etc updated? Is there something done in the path of the PUT to
indicate this object belongs to a particular container and the number
of bytes etc is done in the background? A little clarification would

4. For the global clusters, is the object ring across regions or is it
the same with containers and accounts also?

5. For containers in global clusters, if a client queries the
container metadata from another site, is there a chance of it getting
the old metadata? With respect to the object itself, the eventually
consistent part is a bit confusing for me:)


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