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
 181 Common Storage Properties
 182 ~~~~~~~~~~~~~~~~~~~~~~~~~
 183
 184 A few storage properties are common among different storage types.
 185
 186 nodes::
 187
 188 List of cluster node names where this storage is
 189 usable/accessible. One can use this property to restrict storage
 190 access to a limited set of nodes.
 191
 192 content::
 193
 194 A storage can support several content types, for example virtual disk
 195 images, cdrom iso images, container templates or container root
 196 directories. Not all storage types support all content types. One can set
 197 this property to select what this storage is used for.
 198
 199 images:::
 200
 201 QEMU/KVM VM images.
 202
 203 rootdir:::
 204
 205 Allow to store container data.
 206
 207 vztmpl:::
 208
 209 Container templates.
 210
 211 backup:::
 212
 213 Backup files (`vzdump`).
 214
 215 iso:::
 216
 217 ISO images
 218
 219 snippets:::
 220
 221 Snippet files, for example guest hook scripts
 222
 223 shared::
 224
 225 Mark storage as shared.
 226
 227 disable::
 228
 229 You can use this flag to disable the storage completely.
 230
 231 maxfiles::
 232
 233 Deprecated, please use `prune-backups` instead. Maximum number of backup files
 234 per VM. Use `0` for unlimited.
 235
 236 prune-backups::
 237
 238 Retention options for backups. For details, see
 239 xref:vzdump_retention[Backup Retention].
 240
 241 format::
 242
 243 Default image format (`raw|qcow2|vmdk`)
 244
 245 preallocation::
 246
 247 Preallocation mode (`off|metadata|falloc|full`) for `raw` and `qcow2` images on
 248 file-based storages. The default is `metadata`, which is treated like `off` for
 249 `raw` images. When using network storages in combination with large `qcow2`
 250 images, using `off` can help to avoid timeouts.
 251
 252 WARNING: It is not advisable to use the same storage pool on different
 253 {pve} clusters. Some storage operation need exclusive access to the
 254 storage, so proper locking is required. While this is implemented
 255 within a cluster, it does not work between different clusters.
 256
 257
 258 Volumes
 259 -------
 260
 261 We use a special notation to address storage data. When you allocate
 262 data from a storage pool, it returns such a volume identifier. A volume
 263 is identified by the `<STORAGE_ID>`, followed by a storage type
 264 dependent volume name, separated by colon. A valid `<VOLUME_ID>` looks
 265 like:
 266
 267  local:230/example-image.raw
 268
 269  local:iso/debian-501-amd64-netinst.iso
 270
 271  local:vztmpl/debian-5.0-joomla_1.5.9-1_i386.tar.gz
 272
 273  iscsi-storage:0.0.2.scsi-14f504e46494c4500494b5042546d2d646744372d31616d61
 274
 275 To get the file system path for a `<VOLUME_ID>` use:
 276
 277  pvesm path <VOLUME_ID>
 278
 279
 280 Volume Ownership
 281 ~~~~~~~~~~~~~~~~
 282
 283 There exists an ownership relation for `image` type volumes. Each such
 284 volume is owned by a VM or Container. For example volume
 285 `local:230/example-image.raw` is owned by VM 230. Most storage
 286 backends encodes this ownership information into the volume name.
 287
 288 When you remove a VM or Container, the system also removes all
 289 associated volumes which are owned by that VM or Container.
 290
 291
 292 Using the Command Line Interface
 293 --------------------------------
 294
 295 It is recommended to familiarize yourself with the concept behind storage
 296 pools and volume identifiers, but in real life, you are not forced to do any
 297 of those low level operations on the command line. Normally,
 298 allocation and removal of volumes is done by the VM and Container
 299 management tools.
 300
 301 Nevertheless, there is a command line tool called `pvesm` (``{pve}
 302 Storage Manager''), which is able to perform common storage management
 303 tasks.
 304
 305
 306 Examples
 307 ~~~~~~~~
 308
 309 Add storage pools
 310
 311  pvesm add <TYPE> <STORAGE_ID> <OPTIONS>
 312  pvesm add dir <STORAGE_ID> --path <PATH>
 313  pvesm add nfs <STORAGE_ID> --path <PATH> --server <SERVER> --export <EXPORT>
 314  pvesm add lvm <STORAGE_ID> --vgname <VGNAME>
 315  pvesm add iscsi <STORAGE_ID> --portal <HOST[:PORT]> --target <TARGET>
 316
 317 Disable storage pools
 318
 319  pvesm set <STORAGE_ID> --disable 1
 320
 321 Enable storage pools
 322
 323  pvesm set <STORAGE_ID> --disable 0
 324
 325 Change/set storage options
 326
 327  pvesm set <STORAGE_ID> <OPTIONS>
 328  pvesm set <STORAGE_ID> --shared 1
 329  pvesm set local --format qcow2
 330  pvesm set <STORAGE_ID> --content iso
 331
 332 Remove storage pools. This does not delete any data, and does not
 333 disconnect or unmount anything. It just removes the storage
 334 configuration.
 335
 336  pvesm remove <STORAGE_ID>
 337
 338 Allocate volumes
 339
 340  pvesm alloc <STORAGE_ID> <VMID> <name> <size> [--format <raw|qcow2>]
 341
 342 Allocate a 4G volume in local storage. The name is auto-generated if
 343 you pass an empty string as `<name>`
 344
 345  pvesm alloc local <VMID> '' 4G
 346
 347 Free volumes
 348
 349  pvesm free <VOLUME_ID>
 350
 351 WARNING: This really destroys all volume data.
 352
 353 List storage status
 354
 355  pvesm status
 356
 357 List storage contents
 358
 359  pvesm list <STORAGE_ID> [--vmid <VMID>]
 360
 361 List volumes allocated by VMID
 362
 363  pvesm list <STORAGE_ID> --vmid <VMID>
 364
 365 List iso images
 366
 367  pvesm list <STORAGE_ID> --iso
 368
 369 List container templates
 370
 371  pvesm list <STORAGE_ID> --vztmpl
 372
 373 Show file system path for a volume
 374
 375  pvesm path <VOLUME_ID>
 376
 377 Exporting the volume `local:103/vm-103-disk-0.qcow2` to the file `target`.
 378 This is mostly used internally with `pvesm import`.
 379 The stream format qcow2+size is different to the qcow2 format.
 380 Consequently, the exported file cannot simply be attached to a VM.
 381 This also holds for the other formats.
 382
 383  pvesm export local:103/vm-103-disk-0.qcow2 qcow2+size target --with-snapshots 1
 384
 385 ifdef::wiki[]
 386
 387 See Also
 388 --------
 389
 390 * link:/wiki/Storage:_Directory[Storage: Directory]
 391
 392 * link:/wiki/Storage:_GlusterFS[Storage: GlusterFS]
 393
 394 * link:/wiki/Storage:_User_Mode_iSCSI[Storage: User Mode iSCSI]
 395
 396 * link:/wiki/Storage:_iSCSI[Storage: iSCSI]
 397
 398 * link:/wiki/Storage:_LVM[Storage: LVM]
 399
 400 * link:/wiki/Storage:_LVM_Thin[Storage: LVM Thin]
 401
 402 * link:/wiki/Storage:_NFS[Storage: NFS]
 403
 404 * link:/wiki/Storage:_CIFS[Storage: CIFS]
 405
 406 * link:/wiki/Storage:_Proxmox_Backup_Server[Storage: Proxmox Backup Server]
 407
 408 * link:/wiki/Storage:_RBD[Storage: RBD]
 409
 410 * link:/wiki/Storage:_CephFS[Storage: CephFS]
 411
 412 * link:/wiki/Storage:_ZFS[Storage: ZFS]
 413
 414 * link:/wiki/Storage:_ZFS_over_iSCSI[Storage: ZFS over iSCSI]
 415
 416 endif::wiki[]
 417
 418 ifndef::wiki[]
 419
 420 // backend documentation
 421
 422 include::pve-storage-dir.adoc[]
 423
 424 include::pve-storage-nfs.adoc[]
 425
 426 include::pve-storage-cifs.adoc[]
 427
 428 include::pve-storage-pbs.adoc[]
 429
 430 include::pve-storage-glusterfs.adoc[]
 431
 432 include::pve-storage-zfspool.adoc[]
 433
 434 include::pve-storage-lvm.adoc[]
 435
 436 include::pve-storage-lvmthin.adoc[]
 437
 438 include::pve-storage-iscsi.adoc[]
 439
 440 include::pve-storage-iscsidirect.adoc[]
 441
 442 include::pve-storage-rbd.adoc[]
 443
 444 include::pve-storage-cephfs.adoc[]
 445
 446 include::pve-storage-btrfs.adoc[]
 447
 448 include::pve-storage-zfs.adoc[]
 449
 450
 451 ifdef::manvolnum[]
 452 include::pve-copyright.adoc[]
 453 endif::manvolnum[]
 454
 455 endif::wiki[]
 456