Replies: 6 comments 2 replies
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Are you talking about this? |
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What kind of |
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I mean the rbd export on linux cli If use |
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Ah, that probably uses Or it could be used in combination with |
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We have issue #279 filed for rbd_read_iterate2. I don't think seek style interfaces are implemented (in librdb). Where they do exist, in cephfs, the Seek(Hole|Data) whence values don't actually seek the holes or data, they're just stubs (see issue #227). In the short term I suggest doing a simple copy loop as @nixpanic suggests with read calls and perhaps do hole detection yourself (eg. read N-size blocks and if the block is all zeros seek forward in your destination file). In the future, when rbd_read_iterate2 or other hole sensitive calls are available use it as an optimization. It's not pretty but that's today's situation AFAICT. |
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Hi @nixpanic, @phlogistonjohn, the export command in rbd cli does not only dump the sparse contents. It produces a file in a special format that also contains the image metadata and diffs. |
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I'd say no, a full implementation of a cli/function call that fully replicates the rbd command's import and export would be out of scope for go-ceph. I see go-ceph as a set of building blocks that you can use to interact with ceph using public APIs. I'd happily work to add any functions that are missing from go-ceph that are used to implement import/export. Additionally, I don't know how well standardized/documented the file format you mention is. I don't know if the file is constructed by exported library calls or is just private to the rbd cli tool. I would be open to having discussions [1] about how to implement such a thing and helping investigate what calls are used but I don't think go-ceph would be the right place for a full blown implementation. [1] - Thus I have converted the original issue to a discussion. :-) |
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As it seems the rbd export format is stable, documented and versioned. Currently it is at version v2. The documentation link I sent earlier details the structure of this file format so implementing it in go should be straight forward imho. I think it makes sense to have some interoperability with the rbd cli since it is the de-facto standard command line tool for working with RBDs in ceph. I can think more extreme and wonder if we can actually modernize the rbd cli and rewrite it using go on top of go-ceph:) |
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I did not found export func on
rbd.Imagestuct , any idea to implement this?Beta Was this translation helpful? Give feedback.
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