From: Danny Al-Gaaf Date: Fri, 22 Mar 2019 00:37:56 +0000 (+0100) Subject: doc: fix LRC documentation X-Git-Tag: v15.0.0~150^2 X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=c9441c291662286a67a72f454f3e1b633aad3f78;p=ceph-ci.git doc: fix LRC documentation Recovery from a failure in jerasure need only k reads and not k+m-1. Signed-off-by: Danny Al-Gaaf --- diff --git a/doc/rados/operations/erasure-code-lrc.rst b/doc/rados/operations/erasure-code-lrc.rst index eeb07a38575..348fc164d00 100644 --- a/doc/rados/operations/erasure-code-lrc.rst +++ b/doc/rados/operations/erasure-code-lrc.rst @@ -5,14 +5,14 @@ Locally repairable erasure code plugin With the *jerasure* plugin, when an erasure coded object is stored on multiple OSDs, recovering from the loss of one OSD requires reading from all the others. For instance if *jerasure* is configured with -*k=8* and *m=4*, losing one OSD requires reading from the eleven +*k=8* and *m=4*, losing one OSD requires reading from the eight others to repair. The *lrc* erasure code plugin creates local parity chunks to be able to recover using less OSDs. For instance if *lrc* is configured with *k=8*, *m=4* and *l=4*, it will create an additional parity chunk for every four OSDs. When a single OSD is lost, it can be recovered with -only four OSDs instead of eleven. +only four OSDs instead of eight. Erasure code profile examples =============================