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VDEVPROPS(7) Miscellaneous Information Manual VDEVPROPS(7) NAME vdevprops -- native and user-defined properties of ZFS vdevs DESCRIPTION Properties are divided into two types, native properties and user-de- fined (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 mean- ingful in your environment. For more information about user proper- ties, 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 inher- ited from top-level vdevs, with the exception of checksum_n, check- sum_t, io_n, io_t, slow_io_events, 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 This indicates the number of slow I/O operations encoun- tered by this vdev. A slow I/O is defined as an opera- tion that did not complete within the zio_slow_io_ms threshold in milliseconds (30000 by default). For RAIDZ and DRAID configurations, this value also represents the number of times the vdev was identified as an outlier and excluded from participating in read I/O operations. 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 per- formed 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 it- self. The default values for OpenZFS on Linux are 10 er- rors in 600 seconds. For OpenZFS on FreeBSD defaults see zfsd(8). The slow_io_events property controls whether slow I/O events are generated. Even when disabled, slow I/Os will be included in the zpool status -s output. 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. sit_out Only valid for RAIDZ and DRAID vdevs. True when a slow disk outlier was detected and the vdev is currently in a sit out state. This property can be manually set to cause vdevs to sit out. It will also be automatically set by the autosit logic if that is enabled. While sitting out, the vdev will not participate in normal reads, instead its data will be reconstructed as needed from parity. autosit Only valid for RAIDZ and DRAID vdevs. If set, this enables the kernel-level slow disk detection logic. This logic au- tomatically causes any vdevs that are significant negative performance outliers to sit out, as described in the sit_out property. path The path to the device for this vdev allocating If this device should perform new allocations, used to dis- able 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, num- bers, 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 prop- erty names can be at most 256 characters, and cannot begin with a dash ("-"). When making programmatic use of user properties, it is strongly sug- gested 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 vali- dated. 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) FreeBSD 15.0 July 23, 2024 VDEVPROPS(7)
NAME | DESCRIPTION | SEE ALSO
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