On 04/27/2017 11:43 PM, Oleg Kolosov wrote: > Hi Loic, > Of course. > I'm implementing a version of Pyramid Code. In Pyramid you remove one of the > global parities of Reed-Solomon and add one local parity for each local > group. In my version, I'd like to add local parity to the global parity > (meaning that for the case the global parity = 1, it would be replicated). > This way in case of a failure in the global parity, you can reconstruct it > using the replicated node instead of reconstructing it will all K nodes. > > This is my profile: > ceph osd erasure-code-profile set myprofile \ > plugin=lrc \ > mapping=DD_DD___ \ > layers='[ > [ "DD_DD_c_", "" ], > [ "DDc_____", "" ], > [ "___DDc__", "" ], > [ "______Dc", "" ], > ]' \ > ruleset-steps='[ > [ "chooseleaf", "osd", 8 ], > ]'
You could test and see if commenting out the sanity check at https://github.com/ceph/ceph/blob/master/src/erasure-code/jerasure/ErasureCodeJerasure.cc#L89 does the trick. I don't remember enough about this border case to be sure it won't work. You can also give it a try with https://github.com/ceph/ceph/blob/master/src/test/erasure-code/ceph_erasure_code_benchmark.cc Cheers > Regards, > Oleg > > On Fri, Apr 28, 2017 at 12:33 AM, Loic Dachary <[email protected] > <mailto:[email protected]>> wrote: > > Hi Oleg, > > On 04/27/2017 11:23 PM, Oleg Kolosov wrote: > > Hi, > > I'm working on various implementation of LRC codes for study purposes. > The layers implementation in the LRC module is very convenient for this, but > I've came upon a problem in one of the cases. > > I'm interested in having k=1, m=1 in one of the layers. However this > gives out an error: > > Error EINVAL: k=1 must be >= 2 > > > > I should point out that my erasure code has additional layers which are > fine, only this one has k=1, m=1. > > > > What was the reason for this issue? > > Can replication be implemented in one of LRC's layers? > > Could you provide the code for me to reproduce this problem ? Or a > description of the layers ? I implemented this restriction because it made > the code simpler. And also because I could not think of a valid use case. > > Cheers > > -- > Loïc Dachary, Artisan Logiciel Libre > > -- Loïc Dachary, Artisan Logiciel Libre _______________________________________________ ceph-users mailing list [email protected] http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
