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 Indicate that this is a single storage with the same contents on all nodes (or
 232 all listed in the 'nodes' option). It will not make the contents of a local
 233 storage automatically accessible to other nodes, it just marks an already shared
 234 storage as such!
 235
 236 disable::
 237
 238 You can use this flag to disable the storage completely.
 239
 240 maxfiles::
 241
 242 Deprecated, please use `prune-backups` instead. Maximum number of backup files
 243 per VM. Use `0` for unlimited.
 244
 245 prune-backups::
 246
 247 Retention options for backups. For details, see
 248 xref:vzdump_retention[Backup Retention].
 249
 250 format::
 251
 252 Default image format (`raw|qcow2|vmdk`)
 253
 254 preallocation::
 255
 256 Preallocation mode (`off|metadata|falloc|full`) for `raw` and `qcow2` images on
 257 file-based storages. The default is `metadata`, which is treated like `off` for
 258 `raw` images. When using network storages in combination with large `qcow2`
 259 images, using `off` can help to avoid timeouts.
 260
 261 WARNING: It is not advisable to use the same storage pool on different
 262 {pve} clusters. Some storage operation need exclusive access to the
 263 storage, so proper locking is required. While this is implemented
 264 within a cluster, it does not work between different clusters.
 265
 266
 267 Volumes
 268 -------
 269
 270 We use a special notation to address storage data. When you allocate
 271 data from a storage pool, it returns such a volume identifier. A volume
 272 is identified by the `<STORAGE_ID>`, followed by a storage type
 273 dependent volume name, separated by colon. A valid `<VOLUME_ID>` looks
 274 like:
 275
 276  local:230/example-image.raw
 277
 278  local:iso/debian-501-amd64-netinst.iso
 279
 280  local:vztmpl/debian-5.0-joomla_1.5.9-1_i386.tar.gz
 281
 282  iscsi-storage:0.0.2.scsi-14f504e46494c4500494b5042546d2d646744372d31616d61
 283
 284 To get the file system path for a `<VOLUME_ID>` use:
 285
 286  pvesm path <VOLUME_ID>
 287
 288
 289 Volume Ownership
 290 ~~~~~~~~~~~~~~~~
 291
 292 There exists an ownership relation for `image` type volumes. Each such
 293 volume is owned by a VM or Container. For example volume
 294 `local:230/example-image.raw` is owned by VM 230. Most storage
 295 backends encodes this ownership information into the volume name.
 296
 297 When you remove a VM or Container, the system also removes all
 298 associated volumes which are owned by that VM or Container.
 299
 300
 301 Using the Command-line Interface
 302 --------------------------------
 303
 304 It is recommended to familiarize yourself with the concept behind storage
 305 pools and volume identifiers, but in real life, you are not forced to do any
 306 of those low level operations on the command line. Normally,
 307 allocation and removal of volumes is done by the VM and Container
 308 management tools.
 309
 310 Nevertheless, there is a command-line tool called `pvesm` (``{pve}
 311 Storage Manager''), which is able to perform common storage management
 312 tasks.
 313
 314
 315 Examples
 316 ~~~~~~~~
 317
 318 Add storage pools
 319
 320  pvesm add <TYPE> <STORAGE_ID> <OPTIONS>
 321  pvesm add dir <STORAGE_ID> --path <PATH>
 322  pvesm add nfs <STORAGE_ID> --path <PATH> --server <SERVER> --export <EXPORT>
 323  pvesm add lvm <STORAGE_ID> --vgname <VGNAME>
 324  pvesm add iscsi <STORAGE_ID> --portal <HOST[:PORT]> --target <TARGET>
 325
 326 Disable storage pools
 327
 328  pvesm set <STORAGE_ID> --disable 1
 329
 330 Enable storage pools
 331
 332  pvesm set <STORAGE_ID> --disable 0
 333
 334 Change/set storage options
 335
 336  pvesm set <STORAGE_ID> <OPTIONS>
 337  pvesm set <STORAGE_ID> --shared 1
 338  pvesm set local --format qcow2
 339  pvesm set <STORAGE_ID> --content iso
 340
 341 Remove storage pools. This does not delete any data, and does not
 342 disconnect or unmount anything. It just removes the storage
 343 configuration.
 344
 345  pvesm remove <STORAGE_ID>
 346
 347 Allocate volumes
 348
 349  pvesm alloc <STORAGE_ID> <VMID> <name> <size> [--format <raw|qcow2>]
 350
 351 Allocate a 4G volume in local storage. The name is auto-generated if
 352 you pass an empty string as `<name>`
 353
 354  pvesm alloc local <VMID> '' 4G
 355
 356 Free volumes
 357
 358  pvesm free <VOLUME_ID>
 359
 360 WARNING: This really destroys all volume data.
 361
 362 List storage status
 363
 364  pvesm status
 365
 366 List storage contents
 367
 368  pvesm list <STORAGE_ID> [--vmid <VMID>]
 369
 370 List volumes allocated by VMID
 371
 372  pvesm list <STORAGE_ID> --vmid <VMID>
 373
 374 List iso images
 375
 376  pvesm list <STORAGE_ID> --content iso
 377
 378 List container templates
 379
 380  pvesm list <STORAGE_ID> --content vztmpl
 381
 382 Show file system path for a volume
 383
 384  pvesm path <VOLUME_ID>
 385
 386 Exporting the volume `local:103/vm-103-disk-0.qcow2` to the file `target`.
 387 This is mostly used internally with `pvesm import`.
 388 The stream format qcow2+size is different to the qcow2 format.
 389 Consequently, the exported file cannot simply be attached to a VM.
 390 This also holds for the other formats.
 391
 392  pvesm export local:103/vm-103-disk-0.qcow2 qcow2+size target --with-snapshots 1
 393
 394 ifdef::wiki[]
 395
 396 See Also
 397 --------
 398
 399 * link:/wiki/Storage:_Directory[Storage: Directory]
 400
 401 * link:/wiki/Storage:_GlusterFS[Storage: GlusterFS]
 402
 403 * link:/wiki/Storage:_User_Mode_iSCSI[Storage: User Mode iSCSI]
 404
 405 * link:/wiki/Storage:_iSCSI[Storage: iSCSI]
 406
 407 * link:/wiki/Storage:_LVM[Storage: LVM]
 408
 409 * link:/wiki/Storage:_LVM_Thin[Storage: LVM Thin]
 410
 411 * link:/wiki/Storage:_NFS[Storage: NFS]
 412
 413 * link:/wiki/Storage:_CIFS[Storage: CIFS]
 414
 415 * link:/wiki/Storage:_Proxmox_Backup_Server[Storage: Proxmox Backup Server]
 416
 417 * link:/wiki/Storage:_RBD[Storage: RBD]
 418
 419 * link:/wiki/Storage:_CephFS[Storage: CephFS]
 420
 421 * link:/wiki/Storage:_ZFS[Storage: ZFS]
 422
 423 * link:/wiki/Storage:_ZFS_over_ISCSI[Storage: ZFS over ISCSI]
 424
 425 endif::wiki[]
 426
 427 ifndef::wiki[]
 428
 429 // backend documentation
 430
 431 include::pve-storage-dir.adoc[]
 432
 433 include::pve-storage-nfs.adoc[]
 434
 435 include::pve-storage-cifs.adoc[]
 436
 437 include::pve-storage-pbs.adoc[]
 438
 439 include::pve-storage-glusterfs.adoc[]
 440
 441 include::pve-storage-zfspool.adoc[]
 442
 443 include::pve-storage-lvm.adoc[]
 444
 445 include::pve-storage-lvmthin.adoc[]
 446
 447 include::pve-storage-iscsi.adoc[]
 448
 449 include::pve-storage-iscsidirect.adoc[]
 450
 451 include::pve-storage-rbd.adoc[]
 452
 453 include::pve-storage-cephfs.adoc[]
 454
 455 include::pve-storage-btrfs.adoc[]
 456
 457 include::pve-storage-zfs.adoc[]
 458
 459
 460 ifdef::manvolnum[]
 461 include::pve-copyright.adoc[]
 462 endif::manvolnum[]
 463
 464 endif::wiki[]
 465