openstack/swift
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Merge "Add fallocate_reserve to account and container servers."

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Zuul
2018-07-20 08:42:51 +00:00
committed by Gerrit Code Review
parent 791009a6ff 8e651a2d3d
commit 89854250c3
10 changed files with 321 additions and 7 deletions
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doc/source/admin_guide.rst
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@@ -298,10 +298,27 @@ Preventing Disk Full Scenarios
Prevent disk full scenarios by ensuring that the ``proxy-server`` blocks PUT
requests and rsync prevents replication to the specific drives.
You can prevent `proxy-server` PUT requests to low space disks by ensuring
``fallocate_reserve`` is set in the ``object-server.conf``. By default,
``fallocate_reserve`` is set to 1%. This blocks PUT requests that leave the
free disk space below 1% of the disk.
You can prevent `proxy-server` PUT requests to low space disks by
ensuring ``fallocate_reserve`` is set in ``account-server.conf``,
``container-server.conf``, and ``object-server.conf``. By default,
``fallocate_reserve`` is set to 1%. In the object server, this blocks
PUT requests that would leave the free disk space below 1% of the
disk. In the account and container servers, this blocks operations
that will increase account or container database size once the free
disk space falls below 1%.
Setting ``fallocate_reserve`` is highly recommended to avoid filling
disks to 100%. When Swift's disks are completely full, all requests
involving those disks will fail, including DELETE requests that would
otherwise free up space. This is because object deletion includes the
creation of a zero-byte tombstone (.ts) to record the time of the
deletion for replication purposes; this happens prior to deletion of
the object's data. On a completely-full filesystem, that zero-byte .ts
file cannot be created, so the DELETE request will fail and the disk
will remain completely full. If ``fallocate_reserve`` is set, then the
filesystem will have enough space to create the zero-byte .ts file,
and thus the deletion of the object will succeed and free up some
space.
In order to prevent rsync replication to specific drives, firstly
setup ``rsync_module`` per disk in your ``object-replicator``.