Hi, On 10/11/2014 07:20, ZHOU Yuan wrote: > Hi Loic, > > On Mon, Nov 10, 2014 at 6:44 AM, Loic Dachary <loic@xxxxxxxxxxx> wrote: >> >> >> On 05/11/2014 13:57, Jan Pekař wrote:> Hi, >>> >>> is there any possibility to change erasure coding pool parameters ie k and m values on the fly? I want to add more disks to existing erasure pool and change redundancy level. I cannot find it in docs. >> >> Hi, >> >> It is not possible to change k/m on the fly. > > I'm a little confused. Does this mean even if the pool is reported to > be using the updated profile, the one it is actually using is still > the old profile? If the profile has been modified after creating the pool, it means new objects will be created with the new profile and old objects will fail to be decoded and if the total of K+M is greater in the new profile than it was in the first one, it will not have enough OSD to work with because the associated crush ruleset will not map enough of them. >> >>> Changing erasure-code-profile is not working so I assume that is only template for newly created pools. >>> If it is not possible now is it planned in the feature (when)? >> >> Changing these parameters require a re-encoding of all objects. The interim solution is to create another pool and move all the objects from the first pool to the other. > > Is there any a easy way to do this transition other than copy these > objects one by one? > If disk space is an issue, a solution might be to define the old pool as a cache tier and evict its content to the storage tier. I did not test this though and there may be problems I do not yet see. Cheers -- Loïc Dachary, Artisan Logiciel Libre
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