mirror of
https://github.com/ceph/ceph
synced 2024-12-22 19:34:30 +00:00
661 lines
18 KiB
ReStructuredText
661 lines
18 KiB
ReStructuredText
======================
|
|
OSD Config Reference
|
|
======================
|
|
|
|
.. index:: OSD; configuration
|
|
|
|
You can configure Ceph OSD Daemons in the Ceph configuration file, but Ceph OSD
|
|
Daemons can use the default values and a very minimal configuration. A minimal
|
|
Ceph OSD Daemon configuration sets ``osd journal size`` and ``osd host``, and
|
|
uses default values for nearly everything else.
|
|
|
|
Ceph OSD Daemons are numerically identified in incremental fashion, beginning
|
|
with ``0`` using the following convention. ::
|
|
|
|
osd.0
|
|
osd.1
|
|
osd.2
|
|
|
|
In a configuration file, you may specify settings for all Ceph OSD Daemons in
|
|
the cluster by adding configuration settings to the ``[osd]`` section of your
|
|
configuration file. To add settings directly to a specific Ceph OSD Daemon
|
|
(e.g., ``osd host``), enter it in an OSD-specific section of your configuration
|
|
file. For example:
|
|
|
|
.. code-block:: ini
|
|
|
|
[osd]
|
|
osd journal size = 1024
|
|
|
|
[osd.0]
|
|
osd host = osd-host-a
|
|
|
|
[osd.1]
|
|
osd host = osd-host-b
|
|
|
|
|
|
.. index:: OSD; config settings
|
|
|
|
General Settings
|
|
================
|
|
|
|
The following settings provide an Ceph OSD Daemon's ID, and determine paths to
|
|
data and journals. Ceph deployment scripts typically generate the UUID
|
|
automatically. We **DO NOT** recommend changing the default paths for data or
|
|
journals, as it makes it more problematic to troubleshoot Ceph later.
|
|
|
|
The journal size should be at least twice the product of the expected drive
|
|
speed multiplied by ``filestore max sync interval``. However, the most common
|
|
practice is to partition the journal drive (often an SSD), and mount it such
|
|
that Ceph uses the entire partition for the journal.
|
|
|
|
|
|
``osd uuid``
|
|
|
|
:Description: The universally unique identifier (UUID) for the Ceph OSD Daemon.
|
|
:Type: UUID
|
|
:Default: The UUID.
|
|
:Note: The ``osd uuid`` applies to a single Ceph OSD Daemon. The ``fsid``
|
|
applies to the entire cluster.
|
|
|
|
|
|
``osd data``
|
|
|
|
:Description: The path to the OSDs data. You must create the directory when
|
|
deploying Ceph. You should mount a drive for OSD data at this
|
|
mount point. We do not recommend changing the default.
|
|
|
|
:Type: String
|
|
:Default: ``/var/lib/ceph/osd/$cluster-$id``
|
|
|
|
|
|
``osd max write size``
|
|
|
|
:Description: The maximum size of a write in megabytes.
|
|
:Type: 32-bit Integer
|
|
:Default: ``90``
|
|
|
|
|
|
``osd client message size cap``
|
|
|
|
:Description: The largest client data message allowed in memory.
|
|
:Type: 64-bit Integer Unsigned
|
|
:Default: 500MB default. ``500*1024L*1024L``
|
|
|
|
|
|
``osd class dir``
|
|
|
|
:Description: The class path for RADOS class plug-ins.
|
|
:Type: String
|
|
:Default: ``$libdir/rados-classes``
|
|
|
|
|
|
.. index:: OSD; file system
|
|
|
|
File System Settings
|
|
====================
|
|
Ceph builds and mounts file systems which are used for Ceph OSDs.
|
|
|
|
``osd mkfs options {fs-type}``
|
|
|
|
:Description: Options used when creating a new Ceph OSD of type {fs-type}.
|
|
|
|
:Type: String
|
|
:Default for xfs: ``-f -i 2048``
|
|
:Default for other file systems: {empty string}
|
|
|
|
For example::
|
|
``osd mkfs options xfs = -f -d agcount=24``
|
|
|
|
``osd mount options {fs-type}``
|
|
|
|
:Description: Options used when mounting a Ceph OSD of type {fs-type}.
|
|
|
|
:Type: String
|
|
:Default for xfs: ``rw,noatime,inode64``
|
|
:Default for other file systems: ``rw, noatime``
|
|
|
|
For example::
|
|
``osd mount options xfs = rw, noatime, inode64, logbufs=8``
|
|
|
|
|
|
.. index:: OSD; journal settings
|
|
|
|
Journal Settings
|
|
================
|
|
|
|
By default, Ceph expects that you will store an Ceph OSD Daemons journal with
|
|
the following path::
|
|
|
|
/var/lib/ceph/osd/$cluster-$id/journal
|
|
|
|
Without performance optimization, Ceph stores the journal on the same disk as
|
|
the Ceph OSD Daemons data. An Ceph OSD Daemon optimized for performance may use
|
|
a separate disk to store journal data (e.g., a solid state drive delivers high
|
|
performance journaling).
|
|
|
|
Ceph's default ``osd journal size`` is 0, so you will need to set this in your
|
|
``ceph.conf`` file. A journal size should find the product of the ``filestore
|
|
max sync interval`` and the expected throughput, and multiply the product by
|
|
two (2)::
|
|
|
|
osd journal size = {2 * (expected throughput * filestore max sync interval)}
|
|
|
|
The expected throughput number should include the expected disk throughput
|
|
(i.e., sustained data transfer rate), and network throughput. For example,
|
|
a 7200 RPM disk will likely have approximately 100 MB/s. Taking the ``min()``
|
|
of the disk and network throughput should provide a reasonable expected
|
|
throughput. Some users just start off with a 10GB journal size. For
|
|
example::
|
|
|
|
osd journal size = 10000
|
|
|
|
|
|
``osd journal``
|
|
|
|
:Description: The path to the OSD's journal. This may be a path to a file or a
|
|
block device (such as a partition of an SSD). If it is a file,
|
|
you must create the directory to contain it. We recommend using a
|
|
drive separate from the ``osd data`` drive.
|
|
|
|
:Type: String
|
|
:Default: ``/var/lib/ceph/osd/$cluster-$id/journal``
|
|
|
|
|
|
``osd journal size``
|
|
|
|
:Description: The size of the journal in megabytes. If this is 0, and the
|
|
journal is a block device, the entire block device is used.
|
|
Since v0.54, this is ignored if the journal is a block device,
|
|
and the entire block device is used.
|
|
|
|
:Type: 32-bit Integer
|
|
:Default: ``5120``
|
|
:Recommended: Begin with 1GB. Should be at least twice the product of the
|
|
expected speed multiplied by ``filestore max sync interval``.
|
|
|
|
|
|
See `Journal Config Reference`_ for additional details.
|
|
|
|
|
|
Monitor OSD Interaction
|
|
=======================
|
|
|
|
Ceph OSD Daemons check each other's heartbeats and report to monitors
|
|
periodically. Ceph can use default values in many cases. However, if your
|
|
network has latency issues, you may need to adopt longer intervals. See
|
|
`Configuring Monitor/OSD Interaction`_ for a detailed discussion of heartbeats.
|
|
|
|
|
|
Data Placement
|
|
==============
|
|
|
|
See `Pool & PG Config Reference`_ for details.
|
|
|
|
|
|
.. index:: OSD; scrubbing
|
|
|
|
Scrubbing
|
|
=========
|
|
|
|
In addition to making multiple copies of objects, Ceph insures data integrity by
|
|
scrubbing placement groups. Ceph scrubbing is analogous to ``fsck`` on the
|
|
object storage layer. For each placement group, Ceph generates a catalog of all
|
|
objects and compares each primary object and its replicas to ensure that no
|
|
objects are missing or mismatched. Light scrubbing (daily) checks the object
|
|
size and attributes. Deep scrubbing (weekly) reads the data and uses checksums
|
|
to ensure data integrity.
|
|
|
|
Scrubbing is important for maintaining data integrity, but it can reduce
|
|
performance. You can adjust the following settings to increase or decrease
|
|
scrubbing operations.
|
|
|
|
|
|
``osd max scrubs``
|
|
|
|
:Description: The maximum number of simultaneous scrub operations for
|
|
a Ceph OSD Daemon.
|
|
|
|
:Type: 32-bit Int
|
|
:Default: ``1``
|
|
|
|
|
|
``osd scrub thread timeout``
|
|
|
|
:Description: The maximum time in seconds before timing out a scrub thread.
|
|
:Type: 32-bit Integer
|
|
:Default: ``60``
|
|
|
|
|
|
``osd scrub finalize thread timeout``
|
|
|
|
:Description: The maximum time in seconds before timing out a scrub finalize
|
|
thread.
|
|
|
|
:Type: 32-bit Integer
|
|
:Default: ``60*10``
|
|
|
|
|
|
``osd scrub load threshold``
|
|
|
|
:Description: The maximum load. Ceph will not scrub when the system load
|
|
(as defined by ``getloadavg()``) is higher than this number.
|
|
Default is ``0.5``.
|
|
|
|
:Type: Float
|
|
:Default: ``0.5``
|
|
|
|
|
|
``osd scrub min interval``
|
|
|
|
:Description: The maximum interval in seconds for scrubbing the Ceph OSD Daemon
|
|
when the Ceph Storage Cluster load is low.
|
|
|
|
:Type: Float
|
|
:Default: Once per day. ``60*60*24``
|
|
|
|
|
|
``osd scrub max interval``
|
|
|
|
:Description: The maximum interval in seconds for scrubbing the Ceph OSD Daemon
|
|
irrespective of cluster load.
|
|
|
|
:Type: Float
|
|
:Default: Once per week. ``7*60*60*24``
|
|
|
|
|
|
``osd deep scrub interval``
|
|
|
|
:Description: The interval for "deep" scrubbing (fully reading all data). The
|
|
``osd scrub load threshold`` does not affect this setting.
|
|
|
|
:Type: Float
|
|
:Default: Once per week. ``60*60*24*7``
|
|
|
|
|
|
``osd deep scrub stride``
|
|
|
|
:Description: Read size when doing a deep scrub.
|
|
:Type: 32-bit Integer
|
|
:Default: 512 KB. ``524288``
|
|
|
|
|
|
.. index:: OSD; operations settings
|
|
|
|
Operations
|
|
==========
|
|
|
|
Operations settings allow you to configure the number of threads for servicing
|
|
requests. If you set ``osd op threads`` to ``0``, it disables multi-threading.
|
|
By default, Ceph uses two threads with a 30 second timeout and a 30 second
|
|
complaint time if an operation doesn't complete within those time parameters.
|
|
You can set operations priority weights between client operations and
|
|
recovery operations to ensure optimal performance during recovery.
|
|
|
|
|
|
``osd op threads``
|
|
|
|
:Description: The number of threads to service Ceph OSD Daemon operations.
|
|
Set to ``0`` to disable it. Increasing the number may increase
|
|
the request processing rate.
|
|
|
|
:Type: 32-bit Integer
|
|
:Default: ``2``
|
|
|
|
|
|
``osd client op priority``
|
|
|
|
:Description: The priority set for client operations. It is relative to
|
|
``osd recovery op priority``.
|
|
|
|
:Type: 32-bit Integer
|
|
:Default: ``63``
|
|
:Valid Range: 1-63
|
|
|
|
|
|
``osd recovery op priority``
|
|
|
|
:Description: The priority set for recovery operations. It is relative to
|
|
``osd client op priority``.
|
|
|
|
:Type: 32-bit Integer
|
|
:Default: ``10``
|
|
:Valid Range: 1-63
|
|
|
|
|
|
``osd op thread timeout``
|
|
|
|
:Description: The Ceph OSD Daemon operation thread timeout in seconds.
|
|
:Type: 32-bit Integer
|
|
:Default: ``30``
|
|
|
|
|
|
``osd op complaint time``
|
|
|
|
:Description: An operation becomes complaint worthy after the specified number
|
|
of seconds have elapsed.
|
|
|
|
:Type: Float
|
|
:Default: ``30``
|
|
|
|
|
|
``osd disk threads``
|
|
|
|
:Description: The number of disk threads, which are used to perform background
|
|
disk intensive OSD operations such as scrubbing and snap
|
|
trimming.
|
|
|
|
:Type: 32-bit Integer
|
|
:Default: ``1``
|
|
|
|
``osd disk thread ioprio class``
|
|
|
|
:Description: Warning: it will only be used if both ``osd disk thread
|
|
ioprio class`` and ``osd disk thread ioprio priority`` are
|
|
set to a non default value. Sets the ioprio_set(2) I/O
|
|
scheduling ``class`` for the disk thread. Acceptable
|
|
values are ``idle``, ``be`` or ``rt``. The ``idle``
|
|
class means the disk thread will have lower priority
|
|
than any other thread in the OSD. This is useful to slow
|
|
down scrubbing on an OSD that is busy handling client
|
|
operations. ``be`` is the default and is the same
|
|
priority as all other threads in the OSD. ``rt`` means
|
|
the disk thread will have precendence over all other
|
|
threads in the OSD. This is useful if scrubbing is much
|
|
needed and must make progress at the expense of client
|
|
operations. Note: Only works with the Linux Kernel CFQ
|
|
scheduler.
|
|
:Type: String
|
|
:Default: the empty string
|
|
|
|
``osd disk thread ioprio priority``
|
|
|
|
:Description: Warning: it will only be used if both ``osd disk thread
|
|
ioprio class`` and ``osd disk thread ioprio priority`` are
|
|
set to a non default value. It sets the ioprio_set(2)
|
|
I/O scheduling ``priority`` of the disk thread ranging
|
|
from 0 (highest) to 7 (lowest). If all OSDs on a given
|
|
host were in class ``idle`` and compete for I/O
|
|
(i.e. due to controller congestion), it can be used to
|
|
lower the disk thread priority of one OSD to 7 so that
|
|
another OSD with priority 0 can potentially scrub
|
|
faster. Note: Only works with the Linux Kernel CFQ
|
|
scheduler.
|
|
:Type: Integer in the range of 0 to 7 or -1 if not to be used.
|
|
:Default: ``-1``
|
|
|
|
``osd op history size``
|
|
|
|
:Description: The maximum number of completed operations to track.
|
|
:Type: 32-bit Unsigned Integer
|
|
:Default: ``20``
|
|
|
|
|
|
``osd op history duration``
|
|
|
|
:Description: The oldest completed operation to track.
|
|
:Type: 32-bit Unsigned Integer
|
|
:Default: ``600``
|
|
|
|
|
|
``osd op log threshold``
|
|
|
|
:Description: How many operations logs to display at once.
|
|
:Type: 32-bit Integer
|
|
:Default: ``5``
|
|
|
|
.. index:: OSD; backfilling
|
|
|
|
Backfilling
|
|
===========
|
|
|
|
When you add or remove Ceph OSD Daemons to a cluster, the CRUSH algorithm will
|
|
want to rebalance the cluster by moving placement groups to or from Ceph OSD
|
|
Daemons to restore the balance. The process of migrating placement groups and
|
|
the objects they contain can reduce the cluster's operational performance
|
|
considerably. To maintain operational performance, Ceph performs this migration
|
|
with 'backfilling', which allows Ceph to set backfill operations to a lower
|
|
priority than requests to read or write data.
|
|
|
|
|
|
``osd max backfills``
|
|
|
|
:Description: The maximum number of backfills allowed to or from a single OSD.
|
|
:Type: 64-bit Unsigned Integer
|
|
:Default: ``10``
|
|
|
|
|
|
``osd backfill scan min``
|
|
|
|
:Description: The minimum number of objects per backfill scan.
|
|
|
|
:Type: 32-bit Integer
|
|
:Default: ``64``
|
|
|
|
|
|
``osd backfill scan max``
|
|
|
|
:Description: The maximum number of objects per backfill scan.
|
|
|
|
:Type: 32-bit Integer
|
|
:Default: ``512``
|
|
|
|
|
|
``osd backfill full ratio``
|
|
|
|
:Description: Refuse to accept backfill requests when the Ceph OSD Daemon's
|
|
full ratio is above this value.
|
|
|
|
:Type: Float
|
|
:Default: ``0.85``
|
|
|
|
|
|
``osd backfill retry interval``
|
|
|
|
:Description: The number of seconds to wait before retrying backfill requests.
|
|
:Type: Double
|
|
:Default: ``10.0``
|
|
|
|
.. index:: OSD; osdmap
|
|
|
|
OSD Map
|
|
=======
|
|
|
|
OSD maps reflect the OSD daemons operating in the cluster. Over time, the
|
|
number of map epochs increases. Ceph provides some settings to ensure that
|
|
Ceph performs well as the OSD map grows larger.
|
|
|
|
|
|
``osd map dedup``
|
|
|
|
:Description: Enable removing duplicates in the OSD map.
|
|
:Type: Boolean
|
|
:Default: ``true``
|
|
|
|
|
|
``osd map cache size``
|
|
|
|
:Description: The number of OSD maps to keep cached.
|
|
:Type: 32-bit Integer
|
|
:Default: ``500``
|
|
|
|
|
|
``osd map cache bl size``
|
|
|
|
:Description: The size of the in-memory OSD map cache in OSD daemons.
|
|
:Type: 32-bit Integer
|
|
:Default: ``50``
|
|
|
|
|
|
``osd map cache bl inc size``
|
|
|
|
:Description: The size of the in-memory OSD map cache incrementals in
|
|
OSD daemons.
|
|
|
|
:Type: 32-bit Integer
|
|
:Default: ``100``
|
|
|
|
|
|
``osd map message max``
|
|
|
|
:Description: The maximum map entries allowed per MOSDMap message.
|
|
:Type: 32-bit Integer
|
|
:Default: ``100``
|
|
|
|
|
|
|
|
.. index:: OSD; recovery
|
|
|
|
Recovery
|
|
========
|
|
|
|
When the cluster starts or when a Ceph OSD Daemon crashes and restarts, the OSD
|
|
begins peering with other Ceph OSD Daemons before writes can occur. See
|
|
`Monitoring OSDs and PGs`_ for details.
|
|
|
|
If a Ceph OSD Daemon crashes and comes back online, usually it will be out of
|
|
sync with other Ceph OSD Daemons containing more recent versions of objects in
|
|
the placement groups. When this happens, the Ceph OSD Daemon goes into recovery
|
|
mode and seeks to get the latest copy of the data and bring its map back up to
|
|
date. Depending upon how long the Ceph OSD Daemon was down, the OSD's objects
|
|
and placement groups may be significantly out of date. Also, if a failure domain
|
|
went down (e.g., a rack), more than one Ceph OSD Daemon may come back online at
|
|
the same time. This can make the recovery process time consuming and resource
|
|
intensive.
|
|
|
|
To maintain operational performance, Ceph performs recovery with limitations on
|
|
the number recovery requests, threads and object chunk sizes which allows Ceph
|
|
perform well in a degraded state.
|
|
|
|
|
|
``osd recovery delay start``
|
|
|
|
:Description: After peering completes, Ceph will delay for the specified number
|
|
of seconds before starting to recover objects.
|
|
|
|
:Type: Float
|
|
:Default: ``0``
|
|
|
|
|
|
``osd recovery max active``
|
|
|
|
:Description: The number of active recovery requests per OSD at one time. More
|
|
requests will accelerate recovery, but the requests places an
|
|
increased load on the cluster.
|
|
|
|
:Type: 32-bit Integer
|
|
:Default: ``15``
|
|
|
|
|
|
``osd recovery max chunk``
|
|
|
|
:Description: The maximum size of a recovered chunk of data to push.
|
|
:Type: 64-bit Integer Unsigned
|
|
:Default: ``8 << 20``
|
|
|
|
|
|
``osd recovery threads``
|
|
|
|
:Description: The number of threads for recovering data.
|
|
:Type: 32-bit Integer
|
|
:Default: ``1``
|
|
|
|
|
|
``osd recovery thread timeout``
|
|
|
|
:Description: The maximum time in seconds before timing out a recovery thread.
|
|
:Type: 32-bit Integer
|
|
:Default: ``30``
|
|
|
|
|
|
``osd recover clone overlap``
|
|
|
|
:Description: Preserves clone overlap during recovery. Should always be set
|
|
to ``true``.
|
|
|
|
:Type: Boolean
|
|
:Default: ``true``
|
|
|
|
|
|
|
|
Miscellaneous
|
|
=============
|
|
|
|
|
|
``osd snap trim thread timeout``
|
|
|
|
:Description: The maximum time in seconds before timing out a snap trim thread.
|
|
:Type: 32-bit Integer
|
|
:Default: ``60*60*1``
|
|
|
|
|
|
``osd backlog thread timeout``
|
|
|
|
:Description: The maximum time in seconds before timing out a backlog thread.
|
|
:Type: 32-bit Integer
|
|
:Default: ``60*60*1``
|
|
|
|
|
|
``osd default notify timeout``
|
|
|
|
:Description: The OSD default notification timeout (in seconds).
|
|
:Type: 32-bit Integer Unsigned
|
|
:Default: ``30``
|
|
|
|
|
|
``osd check for log corruption``
|
|
|
|
:Description: Check log files for corruption. Can be computationally expensive.
|
|
:Type: Boolean
|
|
:Default: ``false``
|
|
|
|
|
|
``osd remove thread timeout``
|
|
|
|
:Description: The maximum time in seconds before timing out a remove OSD thread.
|
|
:Type: 32-bit Integer
|
|
:Default: ``60*60``
|
|
|
|
|
|
``osd command thread timeout``
|
|
|
|
:Description: The maximum time in seconds before timing out a command thread.
|
|
:Type: 32-bit Integer
|
|
:Default: ``10*60``
|
|
|
|
|
|
``osd command max records``
|
|
|
|
:Description: Limits the number of lost objects to return.
|
|
:Type: 32-bit Integer
|
|
:Default: ``256``
|
|
|
|
|
|
``osd auto upgrade tmap``
|
|
|
|
:Description: Uses ``tmap`` for ``omap`` on old objects.
|
|
:Type: Boolean
|
|
:Default: ``true``
|
|
|
|
|
|
``osd tmapput sets users tmap``
|
|
|
|
:Description: Uses ``tmap`` for debugging only.
|
|
:Type: Boolean
|
|
:Default: ``false``
|
|
|
|
|
|
``osd preserve trimmed log``
|
|
|
|
:Description: Preserves trimmed log files, but uses more disk space.
|
|
:Type: Boolean
|
|
:Default: ``false``
|
|
|
|
|
|
|
|
.. _pool: ../../operations/pools
|
|
.. _Configuring Monitor/OSD Interaction: ../mon-osd-interaction
|
|
.. _Monitoring OSDs and PGs: ../../operations/monitoring-osd-pg#peering
|
|
.. _Pool & PG Config Reference: ../pool-pg-config-ref
|
|
.. _Journal Config Reference: ../journal-ref
|