VDEVPROPS(7)

NAME
vdevprops - native and user-defined properties of ZFS vdevs

DESCRIPTION
Properties are divided into two types, native properties and user-defined (or "user") properties. Native properties either export internal statistics or control ZFS behavior. In addition, native properties are either editable or read-only. User properties have no effect on ZFS behavior, but you can use them to annotate vdevs in a way that is meaningful in your environment. For more information about user properties, see the User Properties section, below.

  Native Properties
Every vdev has a set of properties that export statistics about the vdev as well as control various behaviors. Properties are not inherited from top-level vdevs, with the exception of checksum_n, checksum_t, io_n, io_t, slow_io_n, and slow_io_t.

The values of numeric properties can be specified using human-readable suffixes (for example, k, KB, M, Gb, and so forth, up to Z for zettabyte). The following are all valid (and equal) specifications: 1536M, 1.5g, 1.50GB.

The values of non-numeric properties are case sensitive and must be lowercase.

The following native properties consist of read-only statistics about the vdev. These properties can not be changed.

capacity
    Percentage of vdev space used

state
    state of this vdev such as online, faulted, or offline

guid
    globally unique id of this vdev

asize
    The allocatable size of this vdev

psize
    The physical size of this vdev

ashift
    The physical sector size of this vdev expressed as the power of two

size
    The total size of this vdev

free
    The amount of remaining free space on this vdev

allocated
    The amount of allocated space on this vdev

expandsize
    How much this vdev can expand by

fragmentation
    Percent of fragmentation in this vdev

parity
    The level of parity for this vdev

devid
    The device id for this vdev

physpath
    The physical path to the device

encpath
    The enclosure path to the device

fru Field Replaceable Unit, usually a model number

parent
    Parent of this vdev

children
    Comma separated list of children of this vdev

numchildren
    The number of children belonging to this vdev

read_errors, write_errors, checksum_errors, initialize_errors, trim_errors
    The number of errors of each type encountered by this vdev

slow_ios
    The number of slow I/Os encountered by this vdev, These represent I/O operations that didn't complete in zio_slow_io_ms milliseconds (30000 by default).

null_ops, read_ops, write_ops, free_ops, claim_ops, trim_ops
    The number of I/O operations of each type performed by this vdev

    null_bytes, read_bytes, write_bytes, free_bytes, claim_bytes, trim_bytes The cumulative size of all operations of each type performed by this vdev

removing
    If this device is currently being removed from the pool

trim_support
    Indicates if a leaf device supports trim operations.

The following native properties can be used to change the behavior of a vdev.

checksum_n, checksum_t, io_n, io_t, slow_io_n, slow_io_t
    Tune the fault management daemon by specifying checksum/io thresholds of <N> errors in <T> seconds, respectively. These properties can be set on leaf and top-level vdevs. When the property is set on the leaf and top-level vdev, the value of the leaf vdev will be used. If the property is only set on the top-level vdev, this value will be used. The value of these properties do not persist across vdev replacement. For this reason, it is advisable to set the property on the top-level vdev - not on the leaf vdev itself. The default values for OpenZFS on Linux are 10 errors in 600 seconds. For OpenZFS on FreeBSD defaults see zfsd(8).

comment
    A text comment up to 8192 characters long

bootsize
    The amount of space to reserve for the EFI system partition

failfast
    If this device should propagate BIO errors back to ZFS, used to disable failfast.

path
    The path to the device for this vdev

allocating
    If this device should perform new allocations, used to disable a device when it is scheduled for later removal. See zpool-remove(8).

  User Properties
In addition to the standard native properties, ZFS supports arbitrary user properties. User properties have no effect on ZFS behavior, but applications or administrators can use them to annotate vdevs.

User property names must contain a colon (""): character to distinguish them from native properties. They may contain lowercase letters, numbers, and the following punctuation characters: colon (""):, dash ("-"), period ("")., and underscore ("_"). The expected convention is that the property name is divided into two portions such as module:property, but this namespace is not enforced by ZFS. User property names can be at most 256 characters, and cannot begin with a dash ("-").

When making programmatic use of user properties, it is strongly suggested to use a reversed DNS domain name for the module component of property names to reduce the chance that two independently-developed packages use the same property name for different purposes.

The values of user properties are arbitrary strings and are never validated. Use the zpool set command with a blank value to clear a user property. Property values are limited to 8192 bytes.

SEE ALSO
zpoolprops(7), zpool-set(8)