There may have someone can provide a explanation in detail. Seems there're various cases. I just checked the code of Proxy's object controller. In case of connection failed to a target object device, seems the request will be stop at https://github.com/openstack/swift/blob/master/swift/proxy/controllers/obj.py#L1091.
I'm awaiting for more accurate answers. +Hugo Kuo+ (+886) 935004793 SwiftStack Inc. 2013/11/29 Shao, Minglong <[email protected]> > Thanks Hugo for your reply! > > It’s still very puzzling. Each object server handles the request > independently. > How can the proxy interrupt the PUT request to the good device? > The line of code you referred to does checking before the object server > actually writes anything. > The exception is raised only if the device is not available. > By the time the proxy knows that the object PUT is a failure, the good > object server has most likely passed that checking. > Besides, I don’t see any proxy code that sends “interrupt” to object > servers after it checks quorum. > > Regards, > -Minglong > > From: Kuo Hugo <[email protected]> > Date: Thursday, November 28, 2013 at 5:46 PM > > To: Minglong Shao <[email protected]> > Cc: "[email protected]" <[email protected]> > Subject: Re: [Openstack] [Swift] Container DB update after object PUT > > Proxy will interrupt the PUT request to the only good device. > > Object server returned error to Proxy > https://github.com/openstack/swift/blob/master/swift/obj/server.py#L387 > > > account-server 192.168.56.10 - - "HEAD /d5/390/AUTH_ss" 204 - > "txdc2f2cc49b7b447e91f93-0052970cca" "HEAD http://192.168.56.10/v1/AUTH_ss"; > "proxy-server 23471" 0.0012 "" > container-server 192.168.56.10 - - "HEAD /d3/408/AUTH_ss/con1" 204 - > "txdc2f2cc49b7b447e91f93-0052970cca" "HEAD > http://192.168.56.10/v1/AUTH_ss/con1"; "proxy-server 23471" 0.0011 > object-server 192.168.56.10 - - "PUT /d2/293/AUTH_ss/con1/8" 507 - "PUT > http://192.168.56.10/v1/AUTH_ss/con1/8"; > "txdc2f2cc49b7b447e91f93-0052970cca" "proxy-server 23471" 0.0004 > proxy-server ERROR Insufficient Storage 192.168.56.10:6000/d2 (txn: > txdc2f2cc49b7b447e91f93-0052970cca) > object-server 192.168.56.10 - - "PUT /d1/293/AUTH_ss/con1/8" 507 - "PUT > http://192.168.56.10/v1/AUTH_ss/con1/8"; > "txdc2f2cc49b7b447e91f93-0052970cca" "proxy-server 23471" 0.0002 > proxy-server ERROR Insufficient Storage 192.168.56.10:6000/d1 (txn: > txdc2f2cc49b7b447e91f93-0052970cca) > proxy-server Object PUT returning 503, 1/2 required connections (txn: > txdc2f2cc49b7b447e91f93-0052970cca) > object-server 192.168.56.10 - - "PUT /d0/293/AUTH_ss/con1/8" 499 - "PUT > http://192.168.56.10/v1/AUTH_ss/con1/8"; > "txdc2f2cc49b7b447e91f93-0052970cca" "proxy-server 23471" 0.0050 > proxy-server 192.168.56.10 192.168.56.10 28/Nov/2013/09/28/42 PUT > /v1/AUTH_ss/con1/8 HTTP/1.0 503 - > curl/7.22.0%20%28x86_64-pc-linux-gnu%29%20libcurl/7.22.0%20OpenSSL/1.0.1%20zlib/ > 1.2.3.4%20libidn/1.23%20librtmp/2.3 > ss%2CAUTH_tk8caa909045a940aca3ff980ffa507961 - 118 - > txdc2f2cc49b7b447e91f93-0052970cca - 0.0145 - - > > > > > +Hugo Kuo+ > (+886) 935004793 > SwiftStack Inc. > > > 2013/11/28 Shao, Minglong <[email protected]> > >> Thanks for your reply! >> I understand the three PUTs by the proxy server and how the replicator >> works. >> >> What I don’t understand is the update of the container DB. The update >> is sent by individual object servers which don’t know whether a PUT (from >> the client’s perspective) succeeds. >> Consider the following scenario: >> >> 1. Proxy server sends three requests to three object servers. >> 2. One object server writes the object successfully, sends an update >> to the container DB and an “OK” reply to the proxy server. But the other >> two fail, so they send “failed” to the proxy server. >> 3. The proxy server sends back “failed” to the client because it >> doesn’t meet the quorum. But the container DB still gets the update to >> insert an entry of this object. >> >> I must have missed something. Thanks for your help! >> >> From: Kuo Hugo <[email protected]> >> Date: Thursday, November 28, 2013 at 12:31 PM >> To: Minglong Shao <[email protected]> >> Cc: "[email protected]" <[email protected]> >> Subject: Re: [Openstack] [Swift] Container DB update after object PUT >> >> Proxy sends requests to *three* replicas's object servers >> simultaneously. >> A successful PUT request depends on at least 1/2 replicas were success. >> Or Proxy will return PUT failed to user. >> >> If 1/3 replica is not there, the replicator will handle it later. >> It won't have any problem with container DB. >> >> >> >> >> +Hugo Kuo+ >> (+886) 935004793 >> SwiftStack Inc. >> >> >> 2013/11/28 Shao, Minglong <[email protected]> >> >>> Hi there, >>> >>> After an object server writes an object in the local file system, it >>> updates the container DB asynchronously (send a message to insert an entry >>> in the object table). But the object server doesn’t really know whether the >>> object PUT is considered successful or not because the other two replicas >>> could fail. In this case, the container DB could have an entry for an >>> object which is not successfully PUT. Can someone shed some light on this? >>> Am I missing something? >>> >>> Many thanks! >>> >>> _______________________________________________ >>> Mailing list: >>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack >>> Post to : [email protected] >>> Unsubscribe : >>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack >>> >>> >> >
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