mirror of
https://github.com/ceph/ceph
synced 2024-12-19 01:46:00 +00:00
03e7f9d827
Fixes: https://tracker.ceph.com/issues/44192 Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>
134 lines
4.2 KiB
ReStructuredText
134 lines
4.2 KiB
ReStructuredText
.. _mds-scrub:
|
|
|
|
======================
|
|
Ceph File System Scrub
|
|
======================
|
|
|
|
CephFS provides the cluster admin (operator) to check consistency of a file system
|
|
via a set of scrub commands. Scrub can be classified into two parts:
|
|
|
|
#. Forward Scrub: In which the scrub operation starts at the root of the file system
|
|
(or a sub directory) and looks at everything that can be touched in the hierarchy
|
|
to ensure consistency.
|
|
|
|
#. Backward Scrub: In which the scrub operation looks at every RADOS object in the
|
|
file system pools and maps it back to the file system hierarchy.
|
|
|
|
This document details commands to initiate and control forward scrub (referred as
|
|
scrub thereafter).
|
|
|
|
.. warning::
|
|
|
|
CephFS forward scrubs are started and manipulated on rank 0. All scrub
|
|
commands must be directed at rank 0.
|
|
|
|
Initiate File System Scrub
|
|
==========================
|
|
|
|
To start a scrub operation for a directory tree use the following command::
|
|
|
|
ceph tell mds.<fsname>:0 scrub start <path> [scrubopts] [tag]
|
|
|
|
where ``scrubopts`` is a comma delimited list of ``recursive``, ``force``, or
|
|
``repair`` and ``tag`` is an optional custom string tag (the default is a generated
|
|
UUID). An example command is::
|
|
|
|
ceph tell mds.cephfs:0 scrub start / recursive
|
|
{
|
|
"return_code": 0,
|
|
"scrub_tag": "6f0d204c-6cfd-4300-9e02-73f382fd23c1",
|
|
"mode": "asynchronous"
|
|
}
|
|
|
|
Recursive scrub is asynchronous (as hinted by `mode` in the output above).
|
|
Asynchronous scrubs must be polled using ``scrub status`` to determine the
|
|
status.
|
|
|
|
The scrub tag is used to differentiate scrubs and also to mark each inode's
|
|
first data object in the default data pool (where the backtrace information is
|
|
stored) with a ``scrub_tag`` extended attribute with the value of the tag. You
|
|
can verify an inode was scrubbed by looking at the extended attribute using the
|
|
RADOS utilities.
|
|
|
|
Scrubs work for multiple active MDS (multiple ranks). The scrub is managed by
|
|
rank 0 and distributed across MDS as appropriate.
|
|
|
|
|
|
Monitor (ongoing) File System Scrubs
|
|
====================================
|
|
|
|
Status of ongoing scrubs can be monitored and polled using in `scrub status`
|
|
command. This commands lists out ongoing scrubs (identified by the tag) along
|
|
with the path and options used to initiate the scrub::
|
|
|
|
ceph tell mds.cephfs:0 scrub status
|
|
{
|
|
"status": "scrub active (85 inodes in the stack)",
|
|
"scrubs": {
|
|
"6f0d204c-6cfd-4300-9e02-73f382fd23c1": {
|
|
"path": "/",
|
|
"options": "recursive"
|
|
}
|
|
}
|
|
}
|
|
|
|
`status` shows the number of inodes that are scheduled to be scrubbed at any point in time,
|
|
hence, can change on subsequent `scrub status` invocations. Also, a high level summary of
|
|
scrub operation (which includes the operation state and paths on which scrub is triggered)
|
|
gets displayed in `ceph status`::
|
|
|
|
ceph status
|
|
[...]
|
|
|
|
task status:
|
|
scrub status:
|
|
mds.0: active [paths:/]
|
|
|
|
[...]
|
|
|
|
A scrub is complete when it no longer shows up in this list (although that may
|
|
change in future releases). Any damage will be reported via cluster health warnings.
|
|
|
|
Control (ongoing) File System Scrubs
|
|
====================================
|
|
|
|
- Pause: Pausing ongoing scrub operations results in no new or pending inodes being
|
|
scrubbed after in-flight RADOS ops (for the inodes that are currently being scrubbed)
|
|
finish::
|
|
|
|
ceph tell mds.cephfs:0 scrub pause
|
|
{
|
|
"return_code": 0
|
|
}
|
|
|
|
The ``scrub status`` after pausing reflects the paused state. At this point,
|
|
initiating new scrub operations (via ``scrub start``) would just queue the
|
|
inode for scrub::
|
|
|
|
ceph tell mds.cephfs:0 scrub status
|
|
{
|
|
"status": "PAUSED (66 inodes in the stack)",
|
|
"scrubs": {
|
|
"6f0d204c-6cfd-4300-9e02-73f382fd23c1": {
|
|
"path": "/",
|
|
"options": "recursive"
|
|
}
|
|
}
|
|
}
|
|
|
|
- Resume: Resuming kick starts a paused scrub operation::
|
|
|
|
ceph tell mds.cephfs:0 scrub resume
|
|
{
|
|
"return_code": 0
|
|
}
|
|
|
|
- Abort: Aborting ongoing scrub operations removes pending inodes from the scrub
|
|
queue (thereby aborting the scrub) after in-flight RADOS ops (for the inodes that
|
|
are currently being scrubbed) finish::
|
|
|
|
ceph tell mds.cephfs:0 scrub abort
|
|
{
|
|
"return_code": 0
|
|
}
|