Thanks for sharing.
On Fri, Aug 10, 2012 at 12:31 PM, John Dickinson <m...@not.mn> wrote: > In a standard swift deployment, the proxy server is running behind a load > balancer and/or an SSL terminator. At SwiftStack, we discovered an issue > that may arise from some config parameters in this layer, and we'd like to > share it with other swift deployers. > > Symptom: > > Users updating metadata (ie POST) on larger objects get 503 error > responses. However, there are no error responses logged by swift. > > Cause: > > Since POSTs are implemented, by default, as a server-side copy in swift > and there is no traffic between the user and swift during the server-side > copy, the LB or SSL terminator times out before the operation is done. > > Solution: > > Two options: > > 1) Raise the timeout in the LB/SSL terminator config. For example, with > pound change the "TimeOut" for the swift backend. pound defaults to 15 > seconds. The appropriate value is however log it takes to do a server side > copy of your largest object. If you have a 1gbps network, it will take > about 160 seconds to copy a 5GB object ((8*5*2**30)/((2**30)/4) -- the > divide by 4 is because the 1gbps link is used to read one stream (the > original) and write the new copy (3 replicas)). > > 2) Change the behavior of POSTs to not do a server-side copy. This will > make POSTs faster, but it will prevent all metadata values from being > updated (notably, Content-Type will not be able to be modified with a > POST). Also, this will not make the issue go away with user-initiated > server-side copies. > > I would recommend the first solution, unless your workload makes heavy use > of POSTs. > > Hoep this helps. > > --John > > > > _______________________________________________ > Mailing list: https://launchpad.net/~openstack > Post to : openstack@lists.launchpad.net > Unsubscribe : https://launchpad.net/~openstack > More help : https://help.launchpad.net/ListHelp > >
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