Hi everyone. As a part of GSoC, I will be implementing a tool, to analyse the need of reweighting devices in the crushmap, and assign a score to the reweight-by-utilisation algorithm. Please correct me where I am wrong, and any other suggestions are more than welcome. The tool shall be a python module, in /src/pybind/mgr and it will use Ceph's current python mgr module to get "pg_summary". The parameters that I plan to use are: * The devices utilisation The number of over-filled devices along with the the amount of over-filled%, will generate a score, using t-distribution. The reason, I shall consider only over-filled devices is because one 10% underfilled with 5 2% overfilled devices, is arguably a better situation than one 10% overfilled with 5 2% underfilled devices. The data for expected distribution after optimization can be obtained from python-crush module. * Expected amount of data flow over the network A score for it can be predicted, using the number of PGs that will be swapped during optimization, which can be found in python-crush[1]. However, the number of PGs, might not give a better idea about the amount of data flow, over the network. Hence, using python mgr-module, and obtaining pgmap before and after each optimization step, will give the amount of data flow in the network. * Time for optimization process This will simply keep a note of the time taken to produce an optimized crushmap from the existing one. I would be using data from python-crush[2] and from pg_map (in json format) obtained by sending commands to python mgr module, to gather the values for the required parameters. A weighted combination of this shall determine the score for the optimization algorithm in place. My initial target is to output the results into a file. I would try to merge it with the dashboard plugin in mgr module, after the implementing the tool at first. [1]: http://libcrush.org/main/python-crush/blob/master/tests/test_optimize.py#L460 [2]:http://libcrush.org/main/python-crush/blob/master/ -- Spandan Kumar Sahu IIT Kharagpur -- 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
