X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=ceph%2Fdoc%2Fcephfs%2Fadministration.rst;h=23bd5fc6a991ed222b42b1b7117166eba01b7be8;hb=31f18b776d001752a193a7cec8bb49033c1a904c;hp=7375a7618e459007c3cc6038d6b2c4dfa8d4b765;hpb=40152f1e46a80b3405e5558a442ee632198dfd24;p=ceph.git diff --git a/ceph/doc/cephfs/administration.rst b/ceph/doc/cephfs/administration.rst index 7375a7618..23bd5fc6a 100644 --- a/ceph/doc/cephfs/administration.rst +++ b/ceph/doc/cephfs/administration.rst @@ -42,6 +42,38 @@ creation of multiple filesystems use ``ceph fs flag set enable_multiple true``. fs rm_data_pool +Settings +-------- + +:: + + fs set max_file_size + +CephFS has a configurable maximum file size, and it's 1TB by default. +You may wish to set this limit higher if you expect to store large files +in CephFS. It is a 64-bit field. + +Setting ``max_file_size`` to 0 does not disable the limit. It would +simply limit clients to only creating empty files. + + +Maximum file sizes and performance +---------------------------------- + +CephFS enforces the maximum file size limit at the point of appending to +files or setting their size. It does not affect how anything is stored. + +When users create a file of an enormous size (without necessarily +writing any data to it), some operations (such as deletes) cause the MDS +to have to do a large number of operations to check if any of the RADOS +objects within the range that could exist (according to the file size) +really existed. + +The ``max_file_size`` setting prevents users from creating files that +appear to be eg. exabytes in size, causing load on the MDS as it tries +to enumerate the objects during operations like stats or deletes. + + Daemons ------- @@ -126,6 +158,11 @@ filesystem. Legacy ------ +The ``ceph mds set`` command is the deprecated version of ``ceph fs set``, +from before there was more than one filesystem per cluster. It operates +on whichever filesystem is marked as the default (see ``ceph fs +set-default``.) + :: mds stat