This is great info, John. Thanks. John
John Purrier [email protected] (206) 930-0788 http://www.linkedin.com/in/johnpur On 8/10/12 9:31 AM, "John Dickinson" <[email protected]> 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 : [email protected] >Unsubscribe : https://launchpad.net/~openstack >More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : [email protected] Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
