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    |Plugin type |Level  |Shared|Snapshots|Stable
  71 |ZFS (local)    |zfspool     |both^1^|no    |yes      |yes
  72 |Directory      |dir         |file   |no    |no^2^    |yes
  73 |BTRFS          |btrfs       |file   |no    |yes      |technology preview
  74 |NFS            |nfs         |file   |yes   |no^2^    |yes
  75 |CIFS           |cifs        |file   |yes   |no^2^    |yes
  76 |Proxmox Backup |pbs         |both   |yes   |n/a      |yes
  77 |GlusterFS      |glusterfs   |file   |yes   |no^2^    |yes
  78 |CephFS         |cephfs      |file   |yes   |yes      |yes
  79 |LVM            |lvm         |block  |no^3^ |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^: Disk images for VMs are stored in ZFS volume (zvol) datasets, which provide
  88 block device functionality.
  89
  90 ^2^: On file based storages, snapshots are possible with the 'qcow2' format.
  91
  92 ^3^: It is possible to use LVM on top of an iSCSI or FC-based storage.
  93 That way you get a `shared` LVM storage
  94
  95
  96 Thin Provisioning
  97 ~~~~~~~~~~~~~~~~~
  98
  99 A number of storages, and the QEMU image format `qcow2`, support 'thin
 100 provisioning'.  With thin provisioning activated, only the blocks that
 101 the guest system actually use will be written to the storage.
 102
 103 Say for instance you create a VM with a 32GB hard disk, and after
 104 installing the guest system OS, the root file system of the VM contains
 105 3 GB of data.  In that case only 3GB are written to the storage, even
 106 if the guest VM sees a 32GB hard drive. In this way thin provisioning
 107 allows you to create disk images which are larger than the currently
 108 available storage blocks. You can create large disk images for your
 109 VMs, and when the need arises, add more disks to your storage without
 110 resizing the VMs' file systems.
 111
 112 All storage types which have the ``Snapshots'' feature also support thin
 113 provisioning.
 114
 115 CAUTION: If a storage runs full, all guests using volumes on that
 116 storage receive IO errors. This can cause file system inconsistencies
 117 and may corrupt your data. So it is advisable to avoid
 118 over-provisioning of your storage resources, or carefully observe
 119 free space to avoid such conditions.
 120
 121
 122 Storage Configuration
 123 ---------------------
 124
 125 All {pve} related storage configuration is stored within a single text
 126 file at `/etc/pve/storage.cfg`. As this file is within `/etc/pve/`, it
 127 gets automatically distributed to all cluster nodes. So all nodes
 128 share the same storage configuration.
 129
 130 Sharing storage configuration makes perfect sense for shared storage,
 131 because the same ``shared'' storage is accessible from all nodes. But it is
 132 also useful for local storage types. In this case such local storage
 133 is available on all nodes, but it is physically different and can have
 134 totally different content.
 135
 136
 137 Storage Pools
 138 ~~~~~~~~~~~~~
 139
 140 Each storage pool has a `<type>`, and is uniquely identified by its
 141 `<STORAGE_ID>`. A pool configuration looks like this:
 142
 143 ----
 144 <type>: <STORAGE_ID>
 145         <property> <value>
 146         <property> <value>
 147         <property>
 148         ...
 149 ----
 150
 151 The `<type>: <STORAGE_ID>` line starts the pool definition, which is then
 152 followed by a list of properties. Most properties require a value. Some have
 153 reasonable defaults, in which case you can omit the value.
 154
 155 To be more specific, take a look at the default storage configuration
 156 after installation. It contains one special local storage pool named
 157 `local`, which refers to the directory `/var/lib/vz` and is always
 158 available. The {pve} installer creates additional storage entries
 159 depending on the storage type chosen at installation time.
 160
 161 .Default storage configuration (`/etc/pve/storage.cfg`)
 162 ----
 163 dir: local
 164         path /var/lib/vz
 165         content iso,vztmpl,backup
 166
 167 # default image store on LVM based installation
 168 lvmthin: local-lvm
 169         thinpool data
 170         vgname pve
 171         content rootdir,images
 172
 173 # default image store on ZFS based installation
 174 zfspool: local-zfs
 175         pool rpool/data
 176         sparse
 177         content images,rootdir
 178 ----
 179
 180 CAUTION: It is problematic to have multiple storage configurations pointing to
 181 the exact same underlying storage. Such an _aliased_ storage configuration can
 182 lead to two different volume IDs ('volid') pointing to the exact same disk
 183 image. {pve} expects that the images' volume IDs point to, are unique. Choosing
 184 different content types for _aliased_ storage configurations can be fine, but
 185 is not recommended.
 186
 187 Common Storage Properties
 188 ~~~~~~~~~~~~~~~~~~~~~~~~~
 189
 190 A few storage properties are common among different storage types.
 191
 192 nodes::
 193
 194 List of cluster node names where this storage is
 195 usable/accessible. One can use this property to restrict storage
 196 access to a limited set of nodes.
 197
 198 content::
 199
 200 A storage can support several content types, for example virtual disk
 201 images, cdrom iso images, container templates or container root
 202 directories. Not all storage types support all content types. One can set
 203 this property to select what this storage is used for.
 204
 205 images:::
 206
 207 QEMU/KVM VM images.
 208
 209 rootdir:::
 210
 211 Allow to store container data.
 212
 213 vztmpl:::
 214
 215 Container templates.
 216
 217 backup:::
 218
 219 Backup files (`vzdump`).
 220
 221 iso:::
 222
 223 ISO images
 224
 225 snippets:::
 226
 227 Snippet files, for example guest hook scripts
 228
 229 shared::
 230
 231 Mark storage as shared.
 232
 233 disable::
 234
 235 You can use this flag to disable the storage completely.
 236
 237 maxfiles::
 238
 239 Deprecated, please use `prune-backups` instead. Maximum number of backup files
 240 per VM. Use `0` for unlimited.
 241
 242 prune-backups::
 243
 244 Retention options for backups. For details, see
 245 xref:vzdump_retention[Backup Retention].
 246
 247 format::
 248
 249 Default image format (`raw|qcow2|vmdk`)
 250
 251 preallocation::
 252
 253 Preallocation mode (`off|metadata|falloc|full`) for `raw` and `qcow2` images on
 254 file-based storages. The default is `metadata`, which is treated like `off` for
 255 `raw` images. When using network storages in combination with large `qcow2`
 256 images, using `off` can help to avoid timeouts.
 257
 258 WARNING: It is not advisable to use the same storage pool on different
 259 {pve} clusters. Some storage operation need exclusive access to the
 260 storage, so proper locking is required. While this is implemented
 261 within a cluster, it does not work between different clusters.
 262
 263
 264 Volumes
 265 -------
 266
 267 We use a special notation to address storage data. When you allocate
 268 data from a storage pool, it returns such a volume identifier. A volume
 269 is identified by the `<STORAGE_ID>`, followed by a storage type
 270 dependent volume name, separated by colon. A valid `<VOLUME_ID>` looks
 271 like:
 272
 273  local:230/example-image.raw
 274
 275  local:iso/debian-501-amd64-netinst.iso
 276
 277  local:vztmpl/debian-5.0-joomla_1.5.9-1_i386.tar.gz
 278
 279  iscsi-storage:0.0.2.scsi-14f504e46494c4500494b5042546d2d646744372d31616d61
 280
 281 To get the file system path for a `<VOLUME_ID>` use:
 282
 283  pvesm path <VOLUME_ID>
 284
 285
 286 Volume Ownership
 287 ~~~~~~~~~~~~~~~~
 288
 289 There exists an ownership relation for `image` type volumes. Each such
 290 volume is owned by a VM or Container. For example volume
 291 `local:230/example-image.raw` is owned by VM 230. Most storage
 292 backends encodes this ownership information into the volume name.
 293
 294 When you remove a VM or Container, the system also removes all
 295 associated volumes which are owned by that VM or Container.
 296
 297
 298 Using the Command Line Interface
 299 --------------------------------
 300
 301 It is recommended to familiarize yourself with the concept behind storage
 302 pools and volume identifiers, but in real life, you are not forced to do any
 303 of those low level operations on the command line. Normally,
 304 allocation and removal of volumes is done by the VM and Container
 305 management tools.
 306
 307 Nevertheless, there is a command line tool called `pvesm` (``{pve}
 308 Storage Manager''), which is able to perform common storage management
 309 tasks.
 310
 311
 312 Examples
 313 ~~~~~~~~
 314
 315 Add storage pools
 316
 317  pvesm add <TYPE> <STORAGE_ID> <OPTIONS>
 318  pvesm add dir <STORAGE_ID> --path <PATH>
 319  pvesm add nfs <STORAGE_ID> --path <PATH> --server <SERVER> --export <EXPORT>
 320  pvesm add lvm <STORAGE_ID> --vgname <VGNAME>
 321  pvesm add iscsi <STORAGE_ID> --portal <HOST[:PORT]> --target <TARGET>
 322
 323 Disable storage pools
 324
 325  pvesm set <STORAGE_ID> --disable 1
 326
 327 Enable storage pools
 328
 329  pvesm set <STORAGE_ID> --disable 0
 330
 331 Change/set storage options
 332
 333  pvesm set <STORAGE_ID> <OPTIONS>
 334  pvesm set <STORAGE_ID> --shared 1
 335  pvesm set local --format qcow2
 336  pvesm set <STORAGE_ID> --content iso
 337
 338 Remove storage pools. This does not delete any data, and does not
 339 disconnect or unmount anything. It just removes the storage
 340 configuration.
 341
 342  pvesm remove <STORAGE_ID>
 343
 344 Allocate volumes
 345
 346  pvesm alloc <STORAGE_ID> <VMID> <name> <size> [--format <raw|qcow2>]
 347
 348 Allocate a 4G volume in local storage. The name is auto-generated if
 349 you pass an empty string as `<name>`
 350
 351  pvesm alloc local <VMID> '' 4G
 352
 353 Free volumes
 354
 355  pvesm free <VOLUME_ID>
 356
 357 WARNING: This really destroys all volume data.
 358
 359 List storage status
 360
 361  pvesm status
 362
 363 List storage contents
 364
 365  pvesm list <STORAGE_ID> [--vmid <VMID>]
 366
 367 List volumes allocated by VMID
 368
 369  pvesm list <STORAGE_ID> --vmid <VMID>
 370
 371 List iso images
 372
 373  pvesm list <STORAGE_ID> --content iso
 374
 375 List container templates
 376
 377  pvesm list <STORAGE_ID> --content vztmpl
 378
 379 Show file system path for a volume
 380
 381  pvesm path <VOLUME_ID>
 382
 383 Exporting the volume `local:103/vm-103-disk-0.qcow2` to the file `target`.
 384 This is mostly used internally with `pvesm import`.
 385 The stream format qcow2+size is different to the qcow2 format.
 386 Consequently, the exported file cannot simply be attached to a VM.
 387 This also holds for the other formats.
 388
 389  pvesm export local:103/vm-103-disk-0.qcow2 qcow2+size target --with-snapshots 1
 390
 391 ifdef::wiki[]
 392
 393 See Also
 394 --------
 395
 396 * link:/wiki/Storage:_Directory[Storage: Directory]
 397
 398 * link:/wiki/Storage:_GlusterFS[Storage: GlusterFS]
 399
 400 * link:/wiki/Storage:_User_Mode_iSCSI[Storage: User Mode iSCSI]
 401
 402 * link:/wiki/Storage:_iSCSI[Storage: iSCSI]
 403
 404 * link:/wiki/Storage:_LVM[Storage: LVM]
 405
 406 * link:/wiki/Storage:_LVM_Thin[Storage: LVM Thin]
 407
 408 * link:/wiki/Storage:_NFS[Storage: NFS]
 409
 410 * link:/wiki/Storage:_CIFS[Storage: CIFS]
 411
 412 * link:/wiki/Storage:_Proxmox_Backup_Server[Storage: Proxmox Backup Server]
 413
 414 * link:/wiki/Storage:_RBD[Storage: RBD]
 415
 416 * link:/wiki/Storage:_CephFS[Storage: CephFS]
 417
 418 * link:/wiki/Storage:_ZFS[Storage: ZFS]
 419
 420 * link:/wiki/Storage:_ZFS_over_iSCSI[Storage: ZFS over iSCSI]
 421
 422 endif::wiki[]
 423
 424 ifndef::wiki[]
 425
 426 // backend documentation
 427
 428 include::pve-storage-dir.adoc[]
 429
 430 include::pve-storage-nfs.adoc[]
 431
 432 include::pve-storage-cifs.adoc[]
 433
 434 include::pve-storage-pbs.adoc[]
 435
 436 include::pve-storage-glusterfs.adoc[]
 437
 438 include::pve-storage-zfspool.adoc[]
 439
 440 include::pve-storage-lvm.adoc[]
 441
 442 include::pve-storage-lvmthin.adoc[]
 443
 444 include::pve-storage-iscsi.adoc[]
 445
 446 include::pve-storage-iscsidirect.adoc[]
 447
 448 include::pve-storage-rbd.adoc[]
 449
 450 include::pve-storage-cephfs.adoc[]
 451
 452 include::pve-storage-btrfs.adoc[]
 453
 454 include::pve-storage-zfs.adoc[]
 455
 456
 457 ifdef::manvolnum[]
 458 include::pve-copyright.adoc[]
 459 endif::manvolnum[]
 460
 461 endif::wiki[]
 462