Communication between proxy and object servers shouldn't be affected by the latency between the proxy server and the client, right? Also, I'm using a single node Swift cluster. So there should be only 1 copy of the object (along with any other I/Os required for the container and accound DBs).
Everything that happens on the Swift side should be the same (if there is no back-n-forth between the Swift server and client) irrespective of how much time it takes for communication between the Swift cluster and the client. I had made one mistake when experimenting with the network_chunk_size and disk_chunk_size config options. These are supposed to go to the object-server.conf and not the proxy-server.conf. I made that change and restarted all the swift servers. However, I don't see any improvement. My current object-server.conf looks like this: http://pastie.org/private/exjiho1cbl80mbruythama What do you think? -Shri On Tue, Jun 24, 2014 at 12:29 AM, Hua ZZ Zhang <zhu...@cn.ibm.com> wrote: > My guess is the object data need to be transmitted to Swift cluster before > the status code returned. > It can't be returned immediately before 2/3 I/O completed. Otherwise it is > not consistent to tell client > it succeed. > > -Edward Zhang > > > [image: Inactive hide details for Shrinand Javadekar ---2014-06-24 下午 > 03:12:14---Shrinand Javadekar <shrin...@maginatics.com>]Shrinand > Javadekar ---2014-06-24 下午 03:12:14---Shrinand Javadekar < > shrin...@maginatics.com> > > > *Shrinand Javadekar <shrin...@maginatics.com > <shrin...@maginatics.com>>* > > 2014-06-24 下午 03:05 > > > To > > > "openstack@lists.openstack.org" <openstack@lists.openstack.org> > > > cc > > > Subject > > > [Openstack] [Swift] PUT requests sensitive to latency? > > > Hi, > > I have a single node swift cluster. I measured the time taken to > complete a PUT request that originated from three different client > machines. Each client was writing a single 256K byte object. > > Note that the time measured was only the time taken on the Swift > cluster itself. I started the timer after the request was received by > the swift proxy-server process and stopped it when that method > returned an HTTP status to the client. This is not the time on the > client side and therefore *ideally* should not be affected by the > latency between the client and the Swift cluster. > > However, it appears that the above is not true. The time required to > complete the request is related to the latency between the client and > swift cluster. > > Here are the results: > > * Client 1: > Ping time 28ms > PUT request time: ~180 ms > > * Client 2: > Ping time 4 ms > PUT request time: ~35 ms > > * Client 3: > Ping time 0.04 ms > PUT request time: ~10 ms > > Details about the experiment: > > * This is a single node Swift installation (not devstack) and uses > SSDs to store metadata as well as data. This is just a test setup. In > production, we won't have SSDs for storing data. > * The above numbers are average of 50 PUT requests. > * The Swift cluster was not being used for anything else during the > experiment. > * The client used was the jclouds library written in java. I had > disable a config option that used the Expect 100-Continue header; i.e. > the requests were not using the Expect 100-Continue header. > * I tried increasing the size of the following options in the > proxy-server.conf and restarting Swift. > disk_chunk_size = 262144 > network_chunk_size = 262144 > ... > [app:proxy-server] > object_chunk_size = 262144 > client_chunk_size = 262144 > > However, this didn't show any improvement in the time required for PUT > requests. > > Am I missing anything? Does Swift require an extra round trip from the > client for completing PUT requests? Any ways of avoiding that? > > Thanks in advance. > -Shri > > _______________________________________________ > Mailing list: > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack > Post to : openstack@lists.openstack.org > Unsubscribe : > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack > > >
_______________________________________________ Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack Post to : openstack@lists.openstack.org Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
