[pve-devel] applied: [PATCH v2 storage] fix #1816: rbd: add support for erasure coded ec pools

[Thomas Lamprecht]

On 28.01.22 12:22, Aaron Lauterer wrote:
> The first step is to allocate rbd images correctly.
> 
> The metadata objects still need to be stored in a replicated pool, but
> by providing the --data-pool parameter on image creation, we can place
> the data objects on the erasure coded (EC) pool.
> 
> Signed-off-by: Aaron Lauterer <a.lauterer at proxmox.com>
> ---
> changes: add data-pool parameter in clone_image() if present
> 
> 
> Right now this only this only affects disk image creation and cloning.
> The EC pool needs to be created manually to test this.
> 
> The Ceph blog about EC with RBD + CephFS gives a nice introduction and
> the necessary steps to set up such a pool [0].
> 
> The steps needed are:
> 
> - create EC profile (a 21 profile is only useful for testing purposes in
>      a 3 node cluster, not something that should be considered for
>      production use!)
> # ceph osd erasure-code-profile set ec-21-profile k=2 m=1 crush-failure-domain=host
> 
> - create a new pool with that profile
> # ceph osd pool create ec21pool erasure ec-21-profile
> 
> - allow overwrite
> # ceph osd pool set ec21pool allow_ec_overwrites true
> 
> - enable application rbd on the pool (the command in the blog seems to
>     have gotten the order of parameters a bit wrong here)
> # ceph osd pool application enable ec21pool rbd
> 
> - add storage configuration
> # pvesm add rbd ectest --pool <replicated pool> --data-pool ec21pool
> 
> For the replicated pool, either create a new one without adding the PVE
> storage config or use a namespace to separate it from the existing pool.
> 
> To create a namespace:
> # rbd namespace create <pool>/<namespace>
> 
> add the '--namespace' parameter in the pvesm add command.
> 
> To check if the objects are stored correclty you can run rados:
> 
> # rados -p <pool> ls
> 
> This should only show metadata objects
> 
> # rados -p <ec pool> ls
> 
> This should then show only `rbd_data.xxx` objects.
> If you configured a namespace, you also need to add the `--namespace`
> parameter to the rados command.
> 
> 
> [0] https://ceph.io/en/news/blog/2017/new-luminous-erasure-coding-rbd-cephfs/
> 

argh, above should have been in the commit message and I overlooked that..

> 
>  PVE/Storage/RBDPlugin.pm | 23 +++++++++++++----------
>  1 file changed, 13 insertions(+), 10 deletions(-)
> 
>

applied, thanks! Made a few followups to improve readbillity, perl captures all
in the last array, e.g.:

my ($a, @foo) = ('a', 'all', @this, 'will', @be_in_foo)