X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=src%2Fceph%2Fdoc%2Frados%2Fconfiguration%2Fjournal-ref.rst;fp=src%2Fceph%2Fdoc%2Frados%2Fconfiguration%2Fjournal-ref.rst;h=0000000000000000000000000000000000000000;hb=7da45d65be36d36b880cc55c5036e96c24b53f00;hp=97300f4a57fe7f6e4f5ed1ae6e766ec6db7d7dd9;hpb=691462d09d0987b47e112d6ee8740375df3c51b2;p=stor4nfv.git diff --git a/src/ceph/doc/rados/configuration/journal-ref.rst b/src/ceph/doc/rados/configuration/journal-ref.rst deleted file mode 100644 index 97300f4..0000000 --- a/src/ceph/doc/rados/configuration/journal-ref.rst +++ /dev/null @@ -1,116 +0,0 @@ -========================== - Journal Config Reference -========================== - -.. index:: journal; journal configuration - -Ceph OSDs use a journal for two reasons: speed and consistency. - -- **Speed:** The journal enables the Ceph OSD Daemon to commit small writes - quickly. Ceph writes small, random i/o to the journal sequentially, which - tends to speed up bursty workloads by allowing the backing filesystem more - time to coalesce writes. The Ceph OSD Daemon's journal, however, can lead - to spiky performance with short spurts of high-speed writes followed by - periods without any write progress as the filesystem catches up to the - journal. - -- **Consistency:** Ceph OSD Daemons require a filesystem interface that - guarantees atomic compound operations. Ceph OSD Daemons write a description - of the operation to the journal and apply the operation to the filesystem. - This enables atomic updates to an object (for example, placement group - metadata). Every few seconds--between ``filestore max sync interval`` and - ``filestore min sync interval``--the Ceph OSD Daemon stops writes and - synchronizes the journal with the filesystem, allowing Ceph OSD Daemons to - trim operations from the journal and reuse the space. On failure, Ceph - OSD Daemons replay the journal starting after the last synchronization - operation. - -Ceph OSD Daemons support the following journal settings: - - -``journal dio`` - -:Description: Enables direct i/o to the journal. Requires ``journal block - align`` set to ``true``. - -:Type: Boolean -:Required: Yes when using ``aio``. -:Default: ``true`` - - - -``journal aio`` - -.. versionchanged:: 0.61 Cuttlefish - -:Description: Enables using ``libaio`` for asynchronous writes to the journal. - Requires ``journal dio`` set to ``true``. - -:Type: Boolean -:Required: No. -:Default: Version 0.61 and later, ``true``. Version 0.60 and earlier, ``false``. - - -``journal block align`` - -:Description: Block aligns write operations. Required for ``dio`` and ``aio``. -:Type: Boolean -:Required: Yes when using ``dio`` and ``aio``. -:Default: ``true`` - - -``journal max write bytes`` - -:Description: The maximum number of bytes the journal will write at - any one time. - -:Type: Integer -:Required: No -:Default: ``10 << 20`` - - -``journal max write entries`` - -:Description: The maximum number of entries the journal will write at - any one time. - -:Type: Integer -:Required: No -:Default: ``100`` - - -``journal queue max ops`` - -:Description: The maximum number of operations allowed in the queue at - any one time. - -:Type: Integer -:Required: No -:Default: ``500`` - - -``journal queue max bytes`` - -:Description: The maximum number of bytes allowed in the queue at - any one time. - -:Type: Integer -:Required: No -:Default: ``10 << 20`` - - -``journal align min size`` - -:Description: Align data payloads greater than the specified minimum. -:Type: Integer -:Required: No -:Default: ``64 << 10`` - - -``journal zero on create`` - -:Description: Causes the file store to overwrite the entire journal with - ``0``'s during ``mkfs``. -:Type: Boolean -:Required: No -:Default: ``false``