Hi, We’ve been operating a ceph storage system storing files using librados (using a replicated pool on rust disks). We implemented a cache over the top of this with SSDs, however we now want to turn this off.
The documentation suggests setting the cache mode to forward before draining the pool, however the ceph management controller spits out an error about this saying that it is unsupported and hence dangerous. The thing is I cannot really locate any documentation as to why it’s considered unsupported and under what conditions it is expected to fail: I have read a passing comment about EC pools having data corruption, but we are using replicated pools. Is this something that is safe to do? Otherwise I have noted the read proxy mode of cache tiers which is documented as a mechanism to transition from write back to disabled, however the documentation is even sparser on this than forward mode. Would this be a better approach if there is some unsupported behaviour in the forward mode cache option? Any thoughts would be appreciated - we really cannot afford to corrupt the data, and I really do not want to have to do some manual software based eviction on this data. regards Stuart − Stuart Harland: Infrastructure Engineer Email: [email protected] <mailto:[email protected]> LiveLink Technology Ltd McCormack House 56A East Street Havant PO9 1BS IMPORTANT: The information transmitted in this e-mail is intended only for the person or entity to whom it is addressed and may contain confidential and/or privileged information. If you are not the intended recipient of this message, please do not read, copy, use or disclose this communication and notify the sender immediately. Any review, retransmission, dissemination or other use of, or taking any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. Any views or opinions presented in this e-mail are solely those of the author and do not necessarily represent those of LiveLink. This e-mail message has been checked for the presence of computer viruses. However, LiveLink is not able to accept liability for any damage caused by this e-mail.
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