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Rbd - Copy-on-read for clones in kernel rbd client » History » Version 1

Jessica Mack, 07/03/2015 09:32 PM

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h1. Rbd - Copy-on-read for clones in kernel rbd client
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h3. Summary
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Add feature copy-on-read in kernel rbd client to improve read performance of clones
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h3. Owners
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* Min Chen (minchen@ubuntukylin.com)
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* Li Wang (liwang@ubuntukylin.com)
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* Name
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h3. Interested Parties
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* Name (Affiliation)
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* Name (Affiliation)
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* Name
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h3. Current Status
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The kernel rbd client does not support clones copy-on-read. We have implement it in librbd 
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at File:/C:\Users\ADMINI~1\AppData\Local\Temp\[5UQ[BL(6~BS2JV6W}N6[%S.pnghttps://github.com/ceph/ceph/pull/1808
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h3. Detailed Description
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Network latency will be the bottleneck of reading object not exist in clone , because it will read object 
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from parent. We will use the same algorithm of copy-on-read in librbd. Firstly, read data from clone if 
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it exists, or else send request to its parent. Secondly, after get the object from parent, in callback function
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write it directly into clone asynchronously with cls copyup. In addition, read the entire object from parent.
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h3. Work items
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h4. Coding tasks
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# Add an copy-on-read option
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# In function rbd_img_obj_request_submit(), sending read request to parent.
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h4. Build / release tasks
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# Task 1
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# Task 2
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# Task 3
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h4. Documentation tasks
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# Task 1
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# Task 2
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# Task 3
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h4. Deprecation tasks
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# Task 1
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# Task 2
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# Task 3