pvesm.adoc

   1 [[chapter_storage]]
   2 ifdef::manvolnum[]
   3 pvesm(1)
   4 ========
   5 :pve-toplevel:
   6
   7 NAME
   8 ----
   9
  10 pvesm - Proxmox VE Storage Manager
  11
  12
  13 SYNOPSIS
  14 --------
  15
  16 include::pvesm.1-synopsis.adoc[]
  17
  18 DESCRIPTION
  19 -----------
  20 endif::manvolnum[]
  21 ifndef::manvolnum[]
  22 {pve} Storage
  23 =============
  24 :pve-toplevel:
  25 endif::manvolnum[]
  26 ifdef::wiki[]
  27 :title: Storage
  28 endif::wiki[]
  29
  30 The {pve} storage model is very flexible. Virtual machine images
  31 can either be stored on one or several local storages, or on shared
  32 storage like NFS or iSCSI (NAS, SAN). There are no limits, and you may
  33 configure as many storage pools as you like. You can use all
  34 storage technologies available for Debian Linux.
  35
  36 One major benefit of storing VMs on shared storage is the ability to
  37 live-migrate running machines without any downtime, as all nodes in
  38 the cluster have direct access to VM disk images. There is no need to
  39 copy VM image data, so live migration is very fast in that case.
  40
  41 The storage library (package `libpve-storage-perl`) uses a flexible
  42 plugin system to provide a common interface to all storage types. This
  43 can be easily adopted to include further storage types in the future.
  44
  45
  46 Storage Types
  47 -------------
  48
  49 There are basically two different classes of storage types:
  50
  51 File level storage::
  52
  53 File level based storage technologies allow access to a fully featured (POSIX)
  54 file system.  They are in general more flexible than any Block level storage
  55 (see below), and allow you to store content of any type. ZFS is probably the
  56 most advanced system, and it has full support for snapshots and clones.
  57
  58 Block level storage::
  59
  60 Allows to store large 'raw' images. It is usually not possible to store
  61 other files (ISO, backups, ..) on such storage types. Most modern
  62 block level storage implementations support snapshots and clones.
  63 RADOS and GlusterFS are distributed systems, replicating storage
  64 data to different nodes.
  65
  66
  67 .Available storage types
  68 [width="100%",cols="<2d,1*m,4*d",options="header"]
  69 |===========================================================
  70 |Description    |PVE type    |Level |Shared|Snapshots|Stable
  71 |ZFS (local)    |zfspool     |file  |no    |yes      |yes
  72 |Directory      |dir         |file  |no    |no^1^    |yes
  73 |BTRFS          |btrfs       |file  |no    |yes      |technology preview
  74 |NFS            |nfs         |file  |yes   |no^1^    |yes
  75 |CIFS           |cifs        |file  |yes   |no^1^    |yes
  76 |Proxmox Backup |pbs         |both  |yes   |n/a      |yes
  77 |GlusterFS      |glusterfs   |file  |yes   |no^1^    |yes
  78 |CephFS         |cephfs      |file  |yes   |yes      |yes
  79 |LVM            |lvm         |block |no^2^ |no       |yes
  80 |LVM-thin       |lvmthin     |block |no    |yes      |yes
  81 |iSCSI/kernel   |iscsi       |block |yes   |no       |yes
  82 |iSCSI/libiscsi |iscsidirect |block |yes   |no       |yes
  83 |Ceph/RBD       |rbd         |block |yes   |yes      |yes
  84 |ZFS over iSCSI |zfs         |block |yes   |yes      |yes
  85 |===========================================================
  86
  87 ^1^: On file based storages, snapshots are possible with the 'qcow2' format.
  88
  89 ^2^: It is possible to use LVM on top of an iSCSI or FC-based storage.
  90 That way you get a `shared` LVM storage.
  91
  92
  93 Thin Provisioning
  94 ~~~~~~~~~~~~~~~~~
  95
  96 A number of storages, and the QEMU image format `qcow2`, support 'thin
  97 provisioning'.  With thin provisioning activated, only the blocks that
  98 the guest system actually use will be written to the storage.
  99
 100 Say for instance you create a VM with a 32GB hard disk, and after
 101 installing the guest system OS, the root file system of the VM contains
 102 3 GB of data.  In that case only 3GB are written to the storage, even
 103 if the guest VM sees a 32GB hard drive. In this way thin provisioning
 104 allows you to create disk images which are larger than the currently
 105 available storage blocks. You can create large disk images for your
 106 VMs, and when the need arises, add more disks to your storage without
 107 resizing the VMs' file systems.
 108
 109 All storage types which have the ``Snapshots'' feature also support thin
 110 provisioning.
 111
 112 CAUTION: If a storage runs full, all guests using volumes on that
 113 storage receive IO errors. This can cause file system inconsistencies
 114 and may corrupt your data. So it is advisable to avoid
 115 over-provisioning of your storage resources, or carefully observe
 116 free space to avoid such conditions.
 117
 118
 119 Storage Configuration
 120 ---------------------
 121
 122 All {pve} related storage configuration is stored within a single text
 123 file at `/etc/pve/storage.cfg`. As this file is within `/etc/pve/`, it
 124 gets automatically distributed to all cluster nodes. So all nodes
 125 share the same storage configuration.
 126
 127 Sharing storage configuration makes perfect sense for shared storage,
 128 because the same ``shared'' storage is accessible from all nodes. But it is
 129 also useful for local storage types. In this case such local storage
 130 is available on all nodes, but it is physically different and can have
 131 totally different content.
 132
 133
 134 Storage Pools
 135 ~~~~~~~~~~~~~
 136
 137 Each storage pool has a `<type>`, and is uniquely identified by its
 138 `<STORAGE_ID>`. A pool configuration looks like this:
 139
 140 ----
 141 <type>: <STORAGE_ID>
 142         <property> <value>
 143         <property> <value>
 144         <property>
 145         ...
 146 ----
 147
 148 The `<type>: <STORAGE_ID>` line starts the pool definition, which is then
 149 followed by a list of properties. Most properties require a value. Some have
 150 reasonable defaults, in which case you can omit the value.
 151
 152 To be more specific, take a look at the default storage configuration
 153 after installation. It contains one special local storage pool named
 154 `local`, which refers to the directory `/var/lib/vz` and is always
 155 available. The {pve} installer creates additional storage entries
 156 depending on the storage type chosen at installation time.
 157
 158 .Default storage configuration (`/etc/pve/storage.cfg`)
 159 ----
 160 dir: local
 161         path /var/lib/vz
 162         content iso,vztmpl,backup
 163
 164 # default image store on LVM based installation
 165 lvmthin: local-lvm
 166         thinpool data
 167         vgname pve
 168         content rootdir,images
 169
 170 # default image store on ZFS based installation
 171 zfspool: local-zfs
 172         pool rpool/data
 173         sparse
 174         content images,rootdir
 175 ----
 176
 177
 178 Common Storage Properties
 179 ~~~~~~~~~~~~~~~~~~~~~~~~~
 180
 181 A few storage properties are common among different storage types.
 182
 183 nodes::
 184
 185 List of cluster node names where this storage is
 186 usable/accessible. One can use this property to restrict storage
 187 access to a limited set of nodes.
 188
 189 content::
 190
 191 A storage can support several content types, for example virtual disk
 192 images, cdrom iso images, container templates or container root
 193 directories. Not all storage types support all content types. One can set
 194 this property to select what this storage is used for.
 195
 196 images:::
 197
 198 QEMU/KVM VM images.
 199
 200 rootdir:::
 201
 202 Allow to store container data.
 203
 204 vztmpl:::
 205
 206 Container templates.
 207
 208 backup:::
 209
 210 Backup files (`vzdump`).
 211
 212 iso:::
 213
 214 ISO images
 215
 216 snippets:::
 217
 218 Snippet files, for example guest hook scripts
 219
 220 shared::
 221
 222 Mark storage as shared.
 223
 224 disable::
 225
 226 You can use this flag to disable the storage completely.
 227
 228 maxfiles::
 229
 230 Deprecated, please use `prune-backups` instead. Maximum number of backup files
 231 per VM. Use `0` for unlimited.
 232
 233 prune-backups::
 234
 235 Retention options for backups. For details, see
 236 xref:vzdump_retention[Backup Retention].
 237
 238 format::
 239
 240 Default image format (`raw|qcow2|vmdk`)
 241
 242 preallocation::
 243
 244 Preallocation mode (`off|metadata|falloc|full`) for `raw` and `qcow2` images on
 245 file-based storages. The default is `metadata`, which is treated like `off` for
 246 `raw` images. When using network storages in combination with large `qcow2`
 247 images, using `off` can help to avoid timeouts.
 248
 249 WARNING: It is not advisable to use the same storage pool on different
 250 {pve} clusters. Some storage operation need exclusive access to the
 251 storage, so proper locking is required. While this is implemented
 252 within a cluster, it does not work between different clusters.
 253
 254
 255 Volumes
 256 -------
 257
 258 We use a special notation to address storage data. When you allocate
 259 data from a storage pool, it returns such a volume identifier. A volume
 260 is identified by the `<STORAGE_ID>`, followed by a storage type
 261 dependent volume name, separated by colon. A valid `<VOLUME_ID>` looks
 262 like:
 263
 264  local:230/example-image.raw
 265
 266  local:iso/debian-501-amd64-netinst.iso
 267
 268  local:vztmpl/debian-5.0-joomla_1.5.9-1_i386.tar.gz
 269
 270  iscsi-storage:0.0.2.scsi-14f504e46494c4500494b5042546d2d646744372d31616d61
 271
 272 To get the file system path for a `<VOLUME_ID>` use:
 273
 274  pvesm path <VOLUME_ID>
 275
 276
 277 Volume Ownership
 278 ~~~~~~~~~~~~~~~~
 279
 280 There exists an ownership relation for `image` type volumes. Each such
 281 volume is owned by a VM or Container. For example volume
 282 `local:230/example-image.raw` is owned by VM 230. Most storage
 283 backends encodes this ownership information into the volume name.
 284
 285 When you remove a VM or Container, the system also removes all
 286 associated volumes which are owned by that VM or Container.
 287
 288
 289 Using the Command Line Interface
 290 --------------------------------
 291
 292 It is recommended to familiarize yourself with the concept behind storage
 293 pools and volume identifiers, but in real life, you are not forced to do any
 294 of those low level operations on the command line. Normally,
 295 allocation and removal of volumes is done by the VM and Container
 296 management tools.
 297
 298 Nevertheless, there is a command line tool called `pvesm` (``{pve}
 299 Storage Manager''), which is able to perform common storage management
 300 tasks.
 301
 302
 303 Examples
 304 ~~~~~~~~
 305
 306 Add storage pools
 307
 308  pvesm add <TYPE> <STORAGE_ID> <OPTIONS>
 309  pvesm add dir <STORAGE_ID> --path <PATH>
 310  pvesm add nfs <STORAGE_ID> --path <PATH> --server <SERVER> --export <EXPORT>
 311  pvesm add lvm <STORAGE_ID> --vgname <VGNAME>
 312  pvesm add iscsi <STORAGE_ID> --portal <HOST[:PORT]> --target <TARGET>
 313
 314 Disable storage pools
 315
 316  pvesm set <STORAGE_ID> --disable 1
 317
 318 Enable storage pools
 319
 320  pvesm set <STORAGE_ID> --disable 0
 321
 322 Change/set storage options
 323
 324  pvesm set <STORAGE_ID> <OPTIONS>
 325  pvesm set <STORAGE_ID> --shared 1
 326  pvesm set local --format qcow2
 327  pvesm set <STORAGE_ID> --content iso
 328
 329 Remove storage pools. This does not delete any data, and does not
 330 disconnect or unmount anything. It just removes the storage
 331 configuration.
 332
 333  pvesm remove <STORAGE_ID>
 334
 335 Allocate volumes
 336
 337  pvesm alloc <STORAGE_ID> <VMID> <name> <size> [--format <raw|qcow2>]
 338
 339 Allocate a 4G volume in local storage. The name is auto-generated if
 340 you pass an empty string as `<name>`
 341
 342  pvesm alloc local <VMID> '' 4G
 343
 344 Free volumes
 345
 346  pvesm free <VOLUME_ID>
 347
 348 WARNING: This really destroys all volume data.
 349
 350 List storage status
 351
 352  pvesm status
 353
 354 List storage contents
 355
 356  pvesm list <STORAGE_ID> [--vmid <VMID>]
 357
 358 List volumes allocated by VMID
 359
 360  pvesm list <STORAGE_ID> --vmid <VMID>
 361
 362 List iso images
 363
 364  pvesm list <STORAGE_ID> --iso
 365
 366 List container templates
 367
 368  pvesm list <STORAGE_ID> --vztmpl
 369
 370 Show file system path for a volume
 371
 372  pvesm path <VOLUME_ID>
 373
 374 Exporting the volume `local:103/vm-103-disk-0.qcow2` to the file `target`.
 375 This is mostly used internally with `pvesm import`.
 376 The stream format qcow2+size is different to the qcow2 format.
 377 Consequently, the exported file cannot simply be attached to a VM.
 378 This also holds for the other formats.
 379
 380  pvesm export local:103/vm-103-disk-0.qcow2 qcow2+size target --with-snapshots 1
 381
 382 ifdef::wiki[]
 383
 384 See Also
 385 --------
 386
 387 * link:/wiki/Storage:_Directory[Storage: Directory]
 388
 389 * link:/wiki/Storage:_GlusterFS[Storage: GlusterFS]
 390
 391 * link:/wiki/Storage:_User_Mode_iSCSI[Storage: User Mode iSCSI]
 392
 393 * link:/wiki/Storage:_iSCSI[Storage: iSCSI]
 394
 395 * link:/wiki/Storage:_LVM[Storage: LVM]
 396
 397 * link:/wiki/Storage:_LVM_Thin[Storage: LVM Thin]
 398
 399 * link:/wiki/Storage:_NFS[Storage: NFS]
 400
 401 * link:/wiki/Storage:_CIFS[Storage: CIFS]
 402
 403 * link:/wiki/Storage:_Proxmox_Backup_Server[Storage: Proxmox Backup Server]
 404
 405 * link:/wiki/Storage:_RBD[Storage: RBD]
 406
 407 * link:/wiki/Storage:_CephFS[Storage: CephFS]
 408
 409 * link:/wiki/Storage:_ZFS[Storage: ZFS]
 410
 411 * link:/wiki/Storage:_ZFS_over_iSCSI[Storage: ZFS over iSCSI]
 412
 413 endif::wiki[]
 414
 415 ifndef::wiki[]
 416
 417 // backend documentation
 418
 419 include::pve-storage-dir.adoc[]
 420
 421 include::pve-storage-nfs.adoc[]
 422
 423 include::pve-storage-cifs.adoc[]
 424
 425 include::pve-storage-pbs.adoc[]
 426
 427 include::pve-storage-glusterfs.adoc[]
 428
 429 include::pve-storage-zfspool.adoc[]
 430
 431 include::pve-storage-lvm.adoc[]
 432
 433 include::pve-storage-lvmthin.adoc[]
 434
 435 include::pve-storage-iscsi.adoc[]
 436
 437 include::pve-storage-iscsidirect.adoc[]
 438
 439 include::pve-storage-rbd.adoc[]
 440
 441 include::pve-storage-cephfs.adoc[]
 442
 443 include::pve-storage-btrfs.adoc[]
 444
 445 include::pve-storage-zfs.adoc[]
 446
 447
 448 ifdef::manvolnum[]
 449 include::pve-copyright.adoc[]
 450 endif::manvolnum[]
 451
 452 endif::wiki[]
 453