Ceph

h1. Specify File layout by kernel client and fuse client

h3. Summary

The file layout defines the stripe strategy of Ceph files, includes stripe count (1 by default), stripe  unit size (4MB by default), object size (4MB by default). Currently, the sole solution to change file layout at run-time is to use libcephfs, which works at a per-file base. Otherwise, it could be changed only at compile-time by revising ‘common/config.cc’, followed a time consuming recompilation. Flexible file layout specification is expected while Ceph is deployed for different types of storage, or for testing. We plan to enable Ceph kernel client, as well as Ceph fuse client to change file layout at run-time. First, the global default layout could be revised by a mount option at mount-time. Second, when a file is just created, being an empty file, ioctl() could be called on it to override the default file layout.

h3. Owners

* Li Wang (UbuntuKylin)

* Name (Affiliation)

* Name

h3. Interested Parties

* Name (Affiliation)

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* Name

h3. Current Status

Under design

h3. Detailed Description

h3. Work items

h4. Coding tasks

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h4. Build / release tasks

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h4. Documentation tasks

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h4. Deprecation tasks

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