On Mon, Nov 7, 2016 at 2:39 AM, Henrik Korkuc <lists@xxxxxxxxx> wrote: > Hey, > > trying to activate forward mode for cache pool results in "Error EPERM: > 'forward' is not a well-supported cache mode and may corrupt your data. > pass --yes-i-really-mean-it to force." > > Change for this message was introduced few months ago and I didn't manage to > find reason for that? Were there cases of data corruption or it's just > because some forwarded ops may fail (e.g. rewrite on EC)? Also there are > examples in docs of forward mode use before deactivating pool, etc. So how > bad it is? > > I want to use it to forward CephFS writes to EC pool (sequential writes, no > rewrites). Cache forwarding has never been well-tested and I haven't watched closely but I think the RADOS team identified some specific scenarios it could fail under. I would definitely not recommend trying to use it in combination with EC pools under CephFS; it might work but no part of the system is trying to cooperate to make it behave. -Greg _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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