[openstack-dev] [Swift] 404 on geo-replicated clusters with write affinity

Clay Gerrard clay.gerrard at gmail.com
Wed May 17 23:22:21 UTC 2017


Hi Bruno,

On Wed, May 17, 2017 at 3:47 PM, Bruno L <teolupus.ext at gmail.com> wrote:

>
> I see multiple bugs in launchpad that are related to this issue.
>

AFAIK, only one bug for this issue is still open, and has the most recent
thoughts added from the Forum

https://bugs.launchpad.net/swift/+bug/1503161

write a brief summary of the changes proposed,
>

I think the skinny of what's in the bug report is "make more backend DELETE
requests to handoffs".

Personally I was coming around to the idea that an explicit configurable
(i.e. similar to "request_node_count" for GET) would be easy to reason
about and give us a lot of flexibility (it would pair well per-policy
configuration WIP https://review.openstack.org/#/c/448240/).  It's possible
this could be implicit using some heuristic over the sort order of
primaries in the ring - but I think it'd be whole 'nother thing, and could
be added later as an "auto" sort of value for the option (i.e. workers =
[N|auto], or "replicas + 2" sort of syntax).

Additionally, it's been pointed out various times that collecting
X-Backend-Timestamp from the responses would allow for further reasoning
over the collected responses in addition to just the status codes (similar
to WIP for GET https://review.openstack.org/#/c/371150/ ) - but I'm
starting to think that'd be an enhancement to the extra handoff DELETE
requests rather than an complete alternative solution.

I don't think anyone really likes the idea of blindly translating a
majority 404 response on DELETE to 204 and calling it a win - so
unfortunately the fix is non-trival.  Glad to see you're interested in
getting your teeth into this one - let me know if there's anything I can do
to help!

Good Luck,

-Clay
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20170517/ca666b6f/attachment.html>


More information about the OpenStack-dev mailing list