ZFS (on Linux) driver¶

Requirements¶

• NFS daemon that can be handled through exportfs app.
• ZFS file system packages, either Kernel or FUSE versions.
• ZFS zpools that are going to be used by Manila should exist and be configured as desired. Manila will not change zpool configuration.
• For remote ZFS hosts according to manila-share service host SSH should be installed.
• For ZFS hosts that support replication:
  • SSH access for each other should be passwordless.
  • Service IP addresses should be available by ZFS hosts for each other.

Supported shared filesystems and operations¶

The driver supports NFS shares.

The following operations are supported:

• Create a share.
• Delete a share.
• Allow share access.
  • Only IP access type is supported.
  • Both access levels are supported - RW and RO.
• Deny share access.
• Bring an existing ZFSOnLinux share under the shared file system service (Managing a share)
• Remove a ZFSOnLinux share from the shared file system service without deleting it (Unmanaging a share)
• Create a snapshot.
• Delete a snapshot.
• Bring an existing ZFSOnLinux snapshot under the shared file system service (Managing a snapshot)
• Remove a ZFSOnLinux snapshot from the shared file system service without deleting it (Unmanaging a snapshot)
• Create a share from snapshot.
• Extend a share.
• Shrink a share.
• Share replication (experimental):
  • Create, update, delete, and promote replica operations are supported.

Possibilities¶

• Any amount of ZFS zpools can be used by share driver.
• Allowed to configure default options for ZFS datasets that are used for share creation.
• Any amount of nested datasets is allowed to be used.
• All share replicas are read-only, only active one is read-write.
• All share replicas are synchronized periodically, not continuously. Status in_sync means latest sync was successful. Time range between syncs equals to the value of the replica_state_update_interval configuration global option.
• Driver can use qualified extra spec zfsonlinux:compression. It can contain any value that ZFS app supports. But if it is disabled through the configuration option with the value compression=off, then it will not be used.

Restrictions¶

The ZFSonLinux share driver has the following restrictions:

• Only IP access type is supported for NFS.
• Only FLAT network is supported.
• Promote share replica operation will switch roles of current secondary replica and active. It does not make more than one active replica available.
• The below items are not yet implemented:
  • SaMBa based sharing.
  • Thick provisioning capability.

Known problems¶

• Promote share replica operation will make ZFS file system that became secondary as RO only on NFS level. On ZFS level system will stay mounted as was - RW.

Back-end configuration¶

The following parameters need to be configured in the manila configuration file for back-ends that use the ZFSonLinux driver:

• share_driver = manila.share.drivers.zfsonlinux.driver.ZFSonLinuxShareDriver
• driver_handles_share_servers = False
• replication_domain = custom_str_value_as_domain_name
  • If empty, then replication will be disabled.
  • If set, then will be able to be used as replication peer for other back ends with the same value.
• zfs_share_export_ip = <user_facing IP address of ZFS host>
• zfs_service_ip = <IP address of service network interface of ZFS host>
• zfs_zpool_list = zpoolname1,zpoolname2/nested_dataset_for_zpool2
  • Can be one or more zpools.
  • Can contain nested datasets.
• zfs_dataset_creation_options = <list of ZFS dataset options>
  • readonly, quota, sharenfs and sharesmb options will be ignored.
• zfs_dataset_name_prefix = <prefix>
  • Prefix to be used in each dataset name.
• zfs_dataset_snapshot_name_prefix = <prefix>
  • Prefix to be used in each dataset snapshot name.
• zfs_use_ssh = <boolean_value>
  • Set False if ZFS located on the same host as manila-share service.
  • Set True if manila-share service should use SSH for ZFS configuration.
• zfs_ssh_username = <ssh_username>
  • Required for replication operations.
  • Required for SSH``ing to ZFS host if zfs_use_ssh is set to True.
• zfs_ssh_user_password = <ssh_user_password>
  • Password for zfs_ssh_username of ZFS host.
  • Used only if zfs_use_ssh is set to True.
• zfs_ssh_private_key_path = <path_to_private_ssh_key>
  • Used only if zfs_use_ssh is set to True.
• zfs_share_helpers = NFS=manila.share.drivers.zfsonlinux.utils.NFSviaZFSHelper
  • Approach for setting up helpers is similar to various other share drivers.
  • At least one helper should be used.
• zfs_replica_snapshot_prefix = <prefix>
  • Prefix to be used in dataset snapshot names that are created by update replica operation.

Driver options¶