Reading! -Sam On Fri, Aug 1, 2014 at 9:28 AM, Marios-Evaggelos Kogias <marioskogias@xxxxxxxxx> wrote: > Hello all, > > my name is Marios Kogias and I am a student at the National Technical > University of Athens. As part of my diploma thesis and my participation in > Google Summer of Code 2014 (in the LTTng organization) I am working on a > low-overhead tracing infrastructure for distributed systems. I am also > collaborating with the Synnefo team (https://www.synnefo.org/) and especially > with Vangelis Koukis, Constantinos Venetsanopoulos and Filippos Giannakos (cc) > > Some time ago, we started experimenting with RADOS instrumentation > using LTTng and > we noticed that there are similar endeavours in the Ceph github repository [1]. > > However, unlike your approach, we are following an annotation-based tracing > schema, which enables us to track a specific request from the time it enters > the system at higher levels till it is finally served by RADOS. > > In general, we try to implement the tracing semantics described in the Dapper > paper [2] in order to trace the causal relationships between the different > processing phases that an IO request may trigger. Our target is an end-to-end > visualisation of the request's route in the system, accompanied by information > concerning latencies in each processing phase. Thanks to LTTng this can happen > with a minimal overhead and in realtime. In order to visualize the results we > have integrated Twitter's Zipkin [3], (which is a tracing system > entirely based on > Dapper) with LTTng. > > You can find a proof of concept of what we've done so far here: > > http://snf-551656.vm.okeanos.grnet.gr:8080/traces/0b554b8a48cb3e84?serviceName=MOSDOp > > In the above link you can see the trace of a write request served by a RADOS > pool with replication level set to 3 (two replicas). > > We'd love to have early feedback and comments from you guys too, > so that we can incorporate useful recommendations. You can find all > the relevant code > here[5][6]. If you have any questions or you wish to experiment with the > project please do not hesitate to contact us. > > Kind regards, > Marios > > [1]https://github.com/ceph/ceph/tree/wip-lttng > [2]http://static.googleusercontent.com/media/research.google.com/el//pubs/archive/36356.pdf > [3]http://twitter.github.io/zipkin/ > [4] https://github.com/marioskogias/blkin > [5] https://github.com/marioskogias/babeltrace-plugins > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
