zpool-add.8

ZPOOL-ADD(8)

System Manager's Manual

ZPOOL-ADD(8)

NAME

zpool-add — add vdevs to ZFS storage pool

SYNOPSIS

zpool add [-fgLnP] [--allow-in-use --allow-replication-mismatch --allow-ashift-mismatch] [-o property=value] pool vdev…

DESCRIPTION

Adds the specified virtual devices to the given pool. The vdev specification is described in the Virtual Devices section of zpoolconcepts(7). The behavior of the -f option, and the device checks performed are described in the zpool create subcommand.

-f: Forces use of vdevs, even if they appear in use, have conflicting ashift values, or specify a conflicting replication level. Not all devices can be overridden in this manner.
-g: Display vdev, GUIDs instead of the normal device names. These GUIDs can be used in place of device names for the zpool detach/offline/remove/replace commands.
-L: Display real paths for vdevs resolving all symbolic links. This can be used to look up the current block device name regardless of the /dev/disk path used to open it.
-n: Displays the configuration that would be used without actually adding the vdevs. The actual pool creation can still fail due to insufficient privileges or device sharing.
-P: Display real paths for vdevs instead of only the last component of the path. This can be used in conjunction with the -L flag.
-o property=value: Sets the given pool properties. See the zpoolprops(7) manual page for a list of valid properties that can be set. The only property supported at the moment is ashift.
--allow-ashift-mismatch: Disable the ashift validation which allows mismatched ashift values in the pool. Adding top-level vdevs with different sector sizes will prohibit future device removal operations, see zpool-remove(8).
--allow-in-use: Allow vdevs to be added even if they might be in use in another pool.
--allow-replication-mismatch: Allow vdevs with conflicting replication levels to be added to the pool.

EXAMPLES

Example 1: Adding a Mirror to a ZFS Storage Pool

The following command adds two mirrored disks to the pool tank, assuming the pool is already made up of two-way mirrors. The additional space is immediately available to any datasets within the pool.

# zpool
  add tank
  mirror
  sda sdb

Example 2: Adding Cache Devices to a ZFS Pool

The following command adds two disks for use as cache devices to a ZFS storage pool:

# zpool
  add pool
  cache
  sdc sdd

Once added, the cache devices gradually fill with content from main memory. Depending on the size of your cache devices, it could take over an hour for them to fill. Capacity and reads can be monitored using the iostat subcommand as follows:

# zpool
  iostat -v pool
  5