ceph/doc/cephfs/administration.rst

   1
   2 CephFS Administrative commands
   3 ==============================
   4
   5 Filesystems
   6 -----------
   7
   8 These commands operate on the CephFS filesystems in your Ceph cluster.
   9 Note that by default only one filesystem is permitted: to enable
  10 creation of multiple filesystems use ``ceph fs flag set enable_multiple true``.
  11
  12 ::
  13
  14     fs new <filesystem name> <metadata pool name> <data pool name>
  15
  16 ::
  17
  18     fs ls
  19
  20 ::
  21
  22     fs rm <filesystem name> [--yes-i-really-mean-it]
  23
  24 ::
  25
  26     fs reset <filesystem name>
  27
  28 ::
  29
  30     fs get <filesystem name>
  31
  32 ::
  33
  34     fs set <filesystem name> <var> <val>
  35
  36 ::
  37
  38     fs add_data_pool <filesystem name> <pool name/id>
  39
  40 ::
  41
  42     fs rm_data_pool <filesystem name> <pool name/id>
  43
  44
  45 Settings
  46 --------
  47
  48 ::
  49
  50     fs set <fs name> max_file_size <size in bytes>
  51
  52 CephFS has a configurable maximum file size, and it's 1TB by default.
  53 You may wish to set this limit higher if you expect to store large files
  54 in CephFS. It is a 64-bit field.
  55
  56 Setting ``max_file_size`` to 0 does not disable the limit. It would
  57 simply limit clients to only creating empty files.
  58
  59
  60 Maximum file sizes and performance
  61 ----------------------------------
  62
  63 CephFS enforces the maximum file size limit at the point of appending to
  64 files or setting their size. It does not affect how anything is stored.
  65
  66 When users create a file of an enormous size (without necessarily
  67 writing any data to it), some operations (such as deletes) cause the MDS
  68 to have to do a large number of operations to check if any of the RADOS
  69 objects within the range that could exist (according to the file size)
  70 really existed.
  71
  72 The ``max_file_size`` setting prevents users from creating files that
  73 appear to be eg. exabytes in size, causing load on the MDS as it tries
  74 to enumerate the objects during operations like stats or deletes.
  75
  76
  77 Daemons
  78 -------
  79
  80 These commands act on specific mds daemons or ranks.
  81
  82 ::
  83
  84     mds fail <gid/name/role
  85
  86 This command deactivates an MDS causing it to flush its entire journal to
  87 backing RADOS objects and close all open client sessions. Deactivating an MDS
  88 is primarily intended for bringing down a rank after reducing the number of
  89 active MDS (max_mds).
  90
  91 ::
  92
  93     mds deactivate <role>
  94
  95 ::
  96
  97     tell mds.<daemon name>
  98
  99 ::
 100
 101     mds metadata <gid/name/role>
 102
 103 ::
 104
 105     mds repaired <role>
 106
 107
 108 Global settings
 109 ---------------
 110
 111 ::
 112
 113     fs dump
 114
 115 ::
 116
 117     fs flag set <flag name> <flag val> [<confirmation string>]
 118
 119 "flag name" must be one of ['enable_multiple']
 120
 121 Some flags require you to confirm your intentions with "--yes-i-really-mean-it"
 122 or a similar string they will prompt you with. Consider these actions carefully
 123 before proceeding; they are placed on especially dangerous activities.
 124
 125
 126 Advanced
 127 --------
 128
 129 These commands are not required in normal operation, and exist
 130 for use in exceptional circumstances.  Incorrect use of these
 131 commands may cause serious problems, such as an inaccessible
 132 filesystem.
 133
 134 ::
 135
 136     mds compat rm_compat
 137
 138 ::
 139
 140     mds compat rm_incompat
 141
 142 ::
 143
 144     mds compat show
 145
 146 ::
 147
 148     mds getmap
 149
 150 ::
 151
 152     mds set_state
 153
 154 ::
 155
 156     mds rmfailed
 157
 158 Legacy
 159 ------
 160
 161 The ``ceph mds set`` command is the deprecated version of ``ceph fs set``,
 162 from before there was more than one filesystem per cluster. It operates
 163 on whichever filesystem is marked as the default (see ``ceph fs
 164 set-default``.)
 165
 166 ::
 167
 168     mds stat
 169     mds dump  # replaced by "fs get"
 170     mds stop  # replaced by "mds deactivate"
 171     mds set_max_mds # replaced by "fs set max_mds"
 172     mds set # replaced by "fs set"
 173     mds cluster_down  # replaced by "fs set cluster_down"
 174     mds cluster_up  # replaced by "fs set cluster_up"
 175     mds newfs # replaced by "fs new"
 176     mds add_data_pool # replaced by "fs add_data_pool"
 177     mds remove_data_pool #replaced by "fs remove_data_pool"
 178