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32 lines
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32 lines
1.5 KiB
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===========================
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File System Recommendations
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===========================
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Ceph OSDs depend on the Extended Attributes (XATTRS) of the underlying file system for:
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- Internal object state
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- Snapshot metadata
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- RADOS Gateway Access Control Lists (ACLs).
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Ceph OSDs rely heavily upon the stability and performance of the underlying file system. The
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underlying file system must provide sufficient capacity for XATTRS. File system candidates for
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Ceph include B tree and B+ tree file systems such as:
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- ``btrfs``
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- ``XFS``
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.. warning:: XATTR limits.
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The RADOS Gateway's ACL and Ceph snapshots easily surpass the 4-kilobyte limit for XATTRs in ``ext4``,
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causing the ``ceph-osd`` process to crash. So ``ext4`` is a poor file system choice if
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you intend to deploy the RADOS Gateway or use snapshots.
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.. tip:: Use `btrfs`
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The Ceph team believes that the best performance and stability will come from ``btrfs.``
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The ``btrfs`` file system has internal transactions that keep the local data set in a consistent state.
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This makes OSDs based on ``btrfs`` simple to deploy, while providing scalability not
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currently available from block-based file systems. The 64-kb XATTR limit for ``xfs``
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XATTRS is enough to accommodate RDB snapshot metadata and RADOS Gateway ACLs. So ``xfs`` is the second-choice
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file system of the Ceph team. If you only plan to use RADOS and ``rbd`` without snapshots and without
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``radosgw``, the ``ext4`` file system should work just fine.
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