vxvol

NAME

vxvol - perform VERITAS Volume Manager operations on volumes

SYNOPSIS

DESCRIPTION

The vxvol utility performs VERITAS Volume Manager (VxVM) operations on volumes. The first operand is a keyword that determines the specific operation to perform. The remaining operands specify configuration records to which the operation is to be applied.

Each operation can be applied to only one disk group at a time. If a disk group is not specified using the -g diskgroup option, the default disk group is determined using the rules described in vxdg(1M).

KEYWORDS

aslog

(VVR only) Associates the named volume with the specified rvg as the VERITAS Volume Replicator log volume. The volume must have a usage-type of gen or fsgen, and cannot have a DRL associated with it.

assoc

(VVR) Associates the named volume with the specified rvg as a data volume. The volume must have a usage-type of gen or fsgen, and cannot have a DRL associated with it.

(Volume Sets) Associates the specified standalone volume, vol, with the volume set, vset. If the -o index option is specified, the value of the index argument is assigned to the volume. If the -o index option is not specified, an index value is assigned automatically.

After the move, any ch_addopt argument string that is specified using the -c option is passed to the vset_addvol content-handler operation (if any). This string indicates how the volume is to be processed by the application. For example, the string may indicate how the volume should be incorporated into a file system. The vset_addvol operation may provide a context string that is stored in the volume record.

dis

(VVR) Dissociates the named volume from its associated rvg.

(Volume Sets) Dissociates the specified volume, vol, from the volume set, vset, and makes it available a standalone volume.

The content-handler string, ch_rmopt, that is specified by the -c option is passed to the vset_rmvol content-handler operation (if any). Typically, the vset_rmvol operation (if any) may choose to reorganize the data in the data set before performing the remove operation, or alternatively, it may cancel the the remove operation altogether.

init

Performs an initialization action on a volume. This can be applied to volumes that were created by vxmake and that have not yet been initialized, or volumes that have been set to the uninitialized state with vxmend fix empty. The action to perform is specified by the init_type operand, which is usage-type-dependent. The volume operand determines which usage type to use for performing the operation.

maint

Detaches each volume named by the volume operands. When a volume is detached, open, read and write operations to the volume fail, although most volume ioctl operations can still be used.

noderecover

When a node in a cluster aborts or crashes, it is not allowed to rejoin the cluster until the active logs of the volumes affected by the crash are recovered. The noderecover operation examines all volumes named by the volume operands and recovers the active log maps corresponding to the crashed nodes, but does not initiate mirror resynchronization. Mirrors are subsequently resynchronized by a vxvol -o force resync volume... command.

This operation is currently applicable only to the volumes with DRL logs and is relevant only in clustered systems.

oem

Not used in this release.

rdpol

Sets the read policy for a volume based on the policy operand. These are the recognized read policies:

prefer

Reads preferentially from the plex named by the plex operand. If the plex is enabled, readable, and associated with the volume, then any read operation on the volume results in a read from that plex if all blocks requested in the read are contained in the plex. The plex operand is required for the prefer read-policy type.

round

Uses a round-robin read order among the enabled, readable plexes associated with the volume. No plex operand should be specified for the round read-policy type.

select

Selects a default policy based on plex associations to the volume. For a volume that contains one enabled, striped plex, the default is to prefer that plex. For any other set of plex associations, the default is to use a round-robin policy. No plex operand should be specified for the select read-policy type.

recover

Some usage types support the concept of recovery of data for objects within a volume different from the mirror resynchronization model. The recover operation is used to specify this type of recovery. The exact procedure for this operation is usage type specific.

resync

Examines all volumes named by the volume operands and perform any synchronization operations that are required. The exact procedure for this operation is usage-type specific.

set

Changes specific volume characteristics. The changes to be made are given by arguments immediately after the set keyword of the form attribute=value. The set of volumes affected by the operation are given after these operands; thus the attribute list ends with an operand that does not contain an equal sign. To allow for volume names that contain an equal sign, an operand of -- can be used to terminate the attribute list. Each usage type represented by the list of volume operands is called once, with the set of all volumes with that usage type.

The set of attribute=value attribute arguments that are recognized depends upon the volume usage type (see the sections on usage types later in this manual page for information on available attributes). However, an attribute argument of the form len=number is expected to be interpreted (if at all) as requesting a change in the length of a volume, regardless of the volume's usage type. The number value is interpreted as a standard length number (see vxintro(1M)).

start

Enables disabled or detached volumes named by the volume operands. The process of enabling a volume is a highly usage-type-dependent operation and may result in transfers of data between plexes associated with the volume.

If the start operation is applied to an uninitialized volume (for example, a volume just created by vxmake), a default initialization is used to initialize and enable the volume.

If the volume is not normally started because failures and disk removals have left all associated plexes with invalid data, the -f option can be used to try to start the volume, anyway. This can be used after replacing disks to enable the volume so that its contents can be restored from backup or reinitialized.

The -a option can be used to start the sub-volumes of a layered volume recursively. (This is the default behavior from VxVM 4.0 onwards.) If the top-level volume in a layered volume fails to start, its sub-volumes are not started.

startall

Attempts to start all volumes that are disabled. If a -U usetype option is specified, then attempt to start all disabled volumes with the indicated usage type. This operation cannot be used to start uninitialized volumes. By default, all volumes in the default disk group (see vxdg(1M)) are started. A different disk group can be specified with the -g option.

The -a option prevents sub-volumes from starting if the top-level volume in a layered volume fails to start.

stop

Disables the enabled or detached volumes named by the volume operands, and prevents the volumes from being opened.

A disk group cannot be deported until all its volumes are closed. The stop operation cannot be used to close a volume that is open to applications. Even if the -f option is specified for an open volume, the volume is disabled but not closed. Failures are returned for any pending or further I/O operations on the volume device.

The -a option stops the sub-volumes of a layered volume recursively. (This is the default behavior from VxVM 4.0 onwards.)

stopall

Attempts to stop all volumes that are currently enabled (see the description of stop for more information).

If the -o usetype option is specified, VxVM attempts to stop all disabled volumes with the indicated usage type. By default, all volumes in the default disk group (see vxdg(1M)) are stopped. A different disk group can be specified with the -g option.

OPTIONS

-f

Forces an operation in some situations where the operation has questionable semantics. For example, -f may be used to reduce the length of a volume with vxvol set, to stop a volume that is currently open or mounted as a file system, or to attempt to start a volume that has no plexes with valid data.

-a

Starts or stops all sub-volumes. If the top layered-volume fails to start or stop, the sub-volumes are not started or stopped.

-c "ch_addopt"

Starts or stops all sub-volumes. If the top layered-volume fails to start or stop, the sub-volumes are not started or stopped.

-c "ch_rmopt"

Specifies a string that is passed to the vset_addvol content handler operation (if any) when a volume is associated with a volume set, or that is passed to the vset_rmvol content handler operation (if any) when a volume is dissociated from a volume set.

-g diskgroup

Specifies the disk group for the operation. The disk group can be specified either by name or by disk group ID. See vxdg(1M) for more information on disk groups.

-m

(VVR only) Maps the data volume to the rvg on the secondary. This is used in the case that the name of the secondary data volume is not the same as that of the corresponding primary data volume. The argument primary_datavol specifies the name of the data volume on the primary.

The current mapping for a secondary volume is given by the primary_datavol field in the long listing of the secondary volume (vxprint -l). If this field is not listed, then global naming is in effect for that data volume, which means that the secondary is using the same name as the primary. The primary_datavol field can also be set for a secondary data volume with vxedit(1M).

-o useopt

Passes in usage-type-specific options to the operation. By convention, the following usage-type-specific options should be implemented by all usage types:

bg

Performs any extended revive operations in background processes after the volume and one or more plexes have been enabled. A volume that is started, or whose length is changed successfully with this option, is usable immediately after the operation completes, although recovery operations may affect performance of the volume for an extended period of time.

delayrecover

Does not perform any plex revive operations when starting a volume. Instead, the volume and any plexes are enabled. This may leave some stale plexes, and may leave a mirrored volume in a special read-writeback (NEEDSYNC) recover state that performs limited plex recovery for each read to the volume.

index

Specifies the index of a volume within a volume set.

iosize=size

Performs recovery operations in regions with the length specified by size, which is a standard VERITAS Volume Manager length number (see vxintro(1M)). Specifying a larger number typically causes the operation to complete sooner, but with greater impact on other processes using the volume. The default I/O size is 1 megabyte.

plexfork[=count]

Performs up to count plex revive operations simultaneously. If no count is specified, then a suitable small number is used (usually 10).

slow[=iodelay]

Reduces the system performance impact of plex recovery operations and volume length changes. Startup recovery and length change consistency operations are usually a set of short operations on small regions of the volume (normally from 16K bytes to 128K bytes). This option inserts a delay between the recovery of each such region. A specific delay can be specified with iodelay as a number of milliseconds, or else a default is chosen (normally 250 milliseconds).

verbose

Prints a message for each volume that is successfully started. Without this option, messages appear only for volumes that fail to start.

-r rvg

(VVR only) Specifies an alternative replicated volume for use as a data or log volume. This option is only used with the assoc and aslog operations.

-q

Waits for the volume daemon if it is not running or available for transactions. If -q is not specified, vxvol aborts if the volume daemon is not available.

-R request_portal

Specifies a rendezvous file path name for regular configuration and query requests. /etc/vx/vold_request is the default.

-t tasktag

If any tasks are registered to track the progress of the operation, mark them with the tag tasktag. The tag specified by tasktag is a sequence of up to 16 alphanumeric characters.

-T taskid

Associates new tasks with the specified parent task ID.

-U usetype

Forces the operation to be performed by the usage-type utility for this usage type.

-V

Displays a list of utilities that would be called from vxvol, along with the arguments that would be passed. The -V option performs a preview run so the utilities are not actually called, and no changes are made to the volume configuration database.

FSGEN AND GEN USAGE TYPES

The fsgen and gen usage types provide the same semantics for all operations of the vxvol utility. However, some options are provided only by the gen usage type.

In addition to the standard -o options required for all usage types, the fsgen and gen usage types provide the following additional options:

force

Forces an operation that is not normally performed as part of the operational model of VxVM and may have adverse effects on data. This is the same as -f.

norecov

Prevents the start operation from recovering plexes through the vxplex utility. Instead, all STALE and ACTIVE plexes are simply treated as equivalent to CLEAN plexes, and are thus enabled without being made consistent. This can be used for volumes whose contents are recreated for each use. Note: This option can only be used with the gen usage type.

An example of a possible use for this attribute is a swap area and the /tmp file system. In the case of /tmp, the model assumes that mkfs is used to create an empty file system after the volume has been started.

Limitations and extensions for the fsgen and gen usage types consist of the following:

init

These are the recognized uses of the vxvol init operation:

vxvol init active volume

Sets the state for all plexes associated with volume to ACTIVE and enables the volume and its plexes. This is used to initialize a single or multiple-plex volume where all plexes are known to have identical contents.

vxvol init clean volume [plex]

Sets the state for the specified plex to CLEAN, and sets all other plexes to STALE. The vxvol start operation can then be used to recover the volume from the CLEAN plex. This operation requires that the volume not be enabled.

If the specified volume has only one plex, then the plex argument is not required as it defaults to that plex. If specified, then the plex argument must represent a plex that is associated with the volume.

vxvol init enable volume

Enables the volume and its plexes but leaves the volume uninitialized. This operation can be used only for non-enabled volumes. It is used to temporarily enable a volume so that data can be loaded onto it to make it consistent. Once the data has been loaded, init active should be used to fully enable the volume. init active could be used, for example, if a complete image of the volume is to be loaded from a tape.

vxvol init zero volume

Writes zero blocks to all plexes in the volume, up to the length of the volume. After the writes complete, the state of each plex is set to ACTIVE and the volume and its plexes are enabled. init zero volume could be used, for example, before running mkfs to put a file system on the volume.

If this operation is interrupted by a signal, then an attempt is made to restore all affected records to their original state, or to a state that is roughly equivalent to their original state. If this attempt is interrupted, such as through another signal, then the user many need to perform some cleanup. A set of commands to perform this cleanup are written to the standard error before the volume utility exits.

maint

The -f option is required to detach an enabled volume. Also, a warning is written to the standard error for volumes that are open or mounted.

resync

Volumes that have possibly differing plex contents are resynchronized to contain consistent data. Any such volumes that are in the NEEDSYNC state are recovered using a read/write-back recovery mode and then put into the ACTIVE state.

Plexes in the SYNC state may already be under recovery and the volume command takes no action to recover them unless the command was invoked with the -o force option.

set

The attributes that can be changed are:

exclusive=yes|y|on|true|no|n|off|false

Sets or clears the EXCLUSIVE flag on the volume. A volume in exclusive open state can be opened by only one node in the cluster at a time. Multiple opens of an exclusive volume from the same node are permitted. Non-exclusive volumes can be simultaneously opened by more than one node. After a node opens an exclusive volume, every other node's open attempt fails until the last close of the volume by the first opener. Such an open failure returns a EBUSY error code. Available only if the VERITAS Volume Manager cluster feature is enabled.

fastresync=yes|y|on|true|no|n|off|false

Enables or disables the FastResync (previously known as Fast Mirror Resynchronization) feature. If enabled, FastResync is non-persistent if no DCO object or DCO volume are associated with a volume. By default, Persistent FastResync is enabled on a volume when a DCO object and DCO volume are created.

fmr=yes|y|on|true|no|n|off|false

Identical to fastresync.

len=number

Changes the length of each volume specified by the volume operands to number sectors. number is a standard VERITAS Volume Manager length number (see vxintro(1M)). Decreasing the length of a volume requires use of -f.

If the volume is enabled, the number of enabled, read-write plexes that would remain complete after the length change is calculated. The operation fails if this number would become zero, but the number of sparse plexes would become greater than 1. Changing the length of a volume with one enabled plex beyond the length of the plex requires use of the -f option.

If the volume is not enabled, the number of CLEAN and ACTIVE plexes that would remain complete after the length change is calculated. The operation fails if this number would become zero, but the number of sparse plexes would become greater than 1. Changing the length of a volume with one enabled plex beyond the length of the plex requires use of the -f option.

To ensure that the new region of the volume is consistent across all plexes of the volume, the volume is put into a SYNC state and read/write-back mode, and a read loop is then performed against the volume. Once this loop has completed, the volume is put back into the ACTIVE state.

loglen=size

Sets the size for logs used with the volume. The size value is a standard VERITAS Volume Manager length numbers (see vxintro(1M)).

logmap_len=size

Specifies the maximum usable size of a DRL or DCM log. This value must be a positive integer multiple of the alignment value for the disk group (see vxdg(1M)).

logtype=type

Sets the type of logging to be used on the volume. This change can be applied only to volumes that are stopped and that have no ACTIVE plexes.

Allowed log types are:

dcm

(VVR only) Used by VVR for srl overflow protection and autosync.

drl

Logs the regions involved in all mirrored or RAID-5 volume writes. (Dirty region logging or DRL is used for speedy recovery after a system crash.)

drlseq

(Sequential DRL) Identical to drl except that the number of dirty bits that can be set in the DRL is limited to the value of the tunable voldrl_max_seq_dirty (default value is 3). This is useful on volumes that are usually written to sequentially, such as database log volumes. Limiting the number of dirty regions allows for faster recovery if a crash occurs. However, if applied to volumes that are written to randomly, this type of logging can be a performance bottleneck as it limits the number of parallel writes that can be carried out.

none

Turns off logging.

undef

Turns off logging until a vxsd aslog or vxplex att operation changes it to drl. See the fsgen and gen sections of vxsd(1M) and vxplex(1M) for more information.

startopts=volume_options

Sets options that are applied to the volume every time the volume is started, independently of options specified with the volume start command. This is a set of comma-separated options of the same form used with the -o option letter. At the present time, only the noattach and verbose options can be applied to volumes in this manner. Unrecognized or inappropriate options are ignored.

start

Starting an uninitialized gen or fsgen volume enables the volume and its plexes, sets the plexes to the ACTIVE state, and recovers the plexes to ensure that each plex has the same contents. If the volume has only one plex, then the volume is immediately set to the ACTIVE state; otherwise, the volume is set to the SYNC state and a special read/write-back mode is set to recover regions of the volume on every read operation. The volume is then read from beginning to end to make all plexes consistent, then the volume is set to the ACTIVE state.

Starting a volume with no active dirty region logging involves enabling all CLEAN and ACTIVE plexes and putting them in the ACTIVE state. If an I/O failure was logged against the plex, or if a disk replacement caused a plex to become stale, then the plex is considered STALE. If any of the subdisks for the plex reside on a removed or inaccessible disk, then the plex is ignored for the purposes of starting the volume.

If two or more plexes were enabled, and if the volume was active at the time the system went down, then the state for the volume is set to SYNC and a special read/write-back recovery mode is used to recover consistency of the volume, segment-by-segment, on every read. A process is then started (in the background with the -o\ bg option) to recover consistency for the entire length of the volume.

If any plexes were considered STALE, then those plexes are attached by calling vxplex att. The number of concurrent plex attach operations are limited based on the rules for -o\ plexfork.

Recovery of plexes with a dirty region log uses the same rules as for volumes without a valid dirty region log, except that recovery of non-stale plexes is done by scanning the contents of the dirty region log and recovering consistency for those regions listed in the log as requiring recovery.

In addition to enabling the volume and managing the recovery of plex consistency, starting a volume clears any transient operations that were being applied to a volume before the system was rebooted. Starting a volume dissociates and removes temporary plexes or subdisks, and dissociates plexes that were being attached if the attach operation did not complete. Snapshot plexes created by vxassist are also removed.

If the volume is unstartable because there are no valid, non-stale plexes and the -f flag is then specified, all STALE plexes that do not contain unusable subdisks (subdisks on failed or removed disks) are changed to ACTIVE. The volume is then started and synchronized from those plexes.

stop

Stopping an fsgen or gen volume disables the volume and its associated plexes. In addition, the utility state for each ACTIVE plex is changed as follows:

• If the plex is detached or disabled, set the state for the plex to STALE. If all plexes are set to STALE, then the volume cannot be started until vxmend is used to change the state of one or more plexes to CLEAN or ACTIVE. A plex normally becomes detached as a result of an I/O error on the plex, or a disk failure or replacement. I/O failures do not normally detach the last remaining enabled plex in a volume, so disk removal operations are the only normal operational method of making a volume unstartable.
• If the plex is volatile, that is, one of the subdisks in the plex is defined on a disk with the volatile attribute (see vxdisk(1M)), then set the plex state to STALE.
• If the volume is enabled and the plex is also enabled, then set the plex state to CLEAN.
• If the volume is detached and the plex is enabled, then the plex state is left as ACTIVE. A volume can be left detached, with remaining valid plexes, only as a result of calling vxvol maint to detach an enabled volume.

Normally, the stop operation fails if any extended operations are using the volume or any of its associated plexes. Such operations are detected as a nonempty value for the tutil0 field in a volume or plex record. If the -f option is specified, then the stop operation ignores volume and plex tutil0 fields.

The -f option must also be given to force the stopping of a volume that is open or mounted as a file system. In this case, a warning message is still written to the standard error, but the stop operation is not otherwise affected. Stopping an open or mounted volume is not normally advisable.

RAID-5 USAGE TYPE

In addition to the standard -o options required for all usage types, the raid5 usage type provides the following options:

checkpt=size

Sets the checkpoint size for a volume. A complete resynchronization of a volume via VOL_R5_RESYNC ioctls can take an extended amount of time. In some circumstances, such as a system crash, the operation may stop before it is complete. To avoid having to restart the synchronization from the beginning of the volume after a certain amount of the volume has been synchronized, a transaction is issued to record the offset to which the resynchronization has completed. This size is called the checkpoint length and can be set using the checkpt option. The default checkpoint length is 64 megabytes.

delayrecover

Prevents the start operation from undergoing some recovery operations. RAID-5 logs, if any are valid, are replayed; however, no parity resynchronizations or subdisk recoveries are performed.

force

Forces an operation that is not normally performed as part of the operational model of VxVM. It may have adverse effects on the data contained by the volume. This is the same as -f.

syncstartok

Allows the delayrecover option to be ignored if the volume must undergo parity resynchronizations or subdisk recoveries before the volume can be enabled.

unsafe

Allows access to certain volumes earlier in the starting process than is normally allowed by the operating process of RAID-5 volumes. This can have adverse effects on the data, and can also result in the RAID-5 volume becoming unusable after a system crash or a power failure.

Limitations and extensions for the raid5 usage type consist of the following:

init

The raid5 usage type recognizes the following uses of the init operation:

vxvol init active volume

Zeros the RAID-5 log plexes, if any, and make the volume available for use. The parity in the volume is marked as stale, though no parity resynchronization is performed; the volume is left with a state of NEEDSYNC.

vxvol init zero volume

Writes zeros to the RAID-5 log plexes, if any, and write zeros to the entire length of the volume. This is achieved by issuing the VOL_R5_ZERO ioctl for the entire altitude of the volume. The volume is left in the ACTIVE state.

recover

The raid5 usage type supports the following invocations of the recover operation:

recover [subdisk ...]

Initiates a recovery of subdisks containing invalid data. If subdisks are specified and are stale, they are recovered in the order specified. This is done by setting the stale and write-only flags on the subdisks and issuing VOL_R5_RECOVER ioctls to regenerate the data. After a successful recovery, the subdisk is marked as non-stale and read-write.

If no subdisk arguments are specified, the subdisks of the RAID-5 plex of the volume are checked to see if they are stale or have invalid contents. If any are found, they are recovered as described above.

resync

Examines the named volumes to see if they are enabled and if the parity in any part of a volume is stale; this is normally indicated by a volume state of NEEDSYNC. If so, the volume is placed in the SYNC state and VOL_R5_RESYNC ioctls are issued to resynchronize the parity in those regions. Upon completion, the volume is placed in the ACTIVE state.

set

The attributes that can be set for raid5 volumes are:

len=number

Changes the length of the volumes specified to be number sectors. number is a standard VERITAS Volume Manager length specification (see vxintro(1M)). Decreasing the length of a volume requires -f.

The volume length cannot be increased such that the RAID-5 plex is sparse in respect to the new volume length; this would make the volume unusable.

In order to assure that the new region of the volume is consistent, the new region of the volume (from the old length to the new length) is filled with zeros by issuing VOL_R5_ZERO ioctls before the length is reset.

loglen=size

Sets the size of the RAID-5 log for the volume. This cannot be set if the volume has no logs. If the length is being increased, the operation is not allowed if it would cause any of the RAID-5 log plexes to become sparse in respect to the new length.

startopts=volume_options

Sets options that are applied to the volume every time the volume is started, independently of options specified with the volume start command. This is a set of comma-separated options of the same form used with the -o option letter. Unrecognized or inappropriate options are ignored.

start

Starting an uninitialized volume (one with a state of EMPTY) zeros any RAID-5 log plexes and then resynchronizes the parity of the volume by issuing VOL_R5_RESYNC ioctls. All subdisks are marked as non-stale and read-write. The volume and RAID-5 plex are then enabled and marked as ACTIVE, and all valid RAID-5 log plexes are marked as LOG. If any RAID-5 log plex proves to be invalid (such as having its NODAREC flag set) its state is set to BADLOG.

Starting a volume that has been shut down cleanly or is not marked as dirty enables the RAID-5 plex and RAID-5 log plexes, and sets the volume kernel state to detached to zero the RAID-5 log plexes for the volume, if any. Once this is completed, all valid RAID-5 log plexes are set to LOG and the volume is enabled and put in the ACTIVE state.

Starting a volume that was not shut down cleanly requires that the parity be resynchronized. If the volume has valid RAID-5 log plexes, the volume is first detached and has its state set to REPLAY, and all log plexes and the RAID-5 plex are enabled. If there are any valid RAID-5 log plexes, their contents are read and their data is written to the appropriate regions of the RAID-5 plex. If reading the RAID-5 logs fails, the logs are marked as invalid and the parity is resynchronized as if there were no logs. Once the replay is complete, the RAID-5 logs are enabled and the volume is enabled and its state is set to ACTIVE.

If the volume needs resynchronization and no valid log plexes exist, the parity must be fully resynchronized. The volume is enabled and its state is set to RESYNC, and the RAID-5 plex is enabled. If usable RAID-5 plexes are available, but contain invalid data, they are zeroed. The parity is then resynchronized by issuing VOL_R5_RESYNC ioctls for the entire length of the volume. Once this is completed, the volume's state is set to ACTIVE. Any usable RAID-5 logs are enabled and set to the LOG state.

If a volume requires full resynchronization (that is, has no usable logs) and the RAID-5 plex has stale or unusable subdisks, the volume is unusable and the start operation fails. This can be overridden by using the -f flag or the -o force option. In this case, any stale subdisks are marked as non-stale and a full resynchronization is performed; however, this may result in some invalid data being introduced into the volume. If multiple subdisks at the same altitude in the RAID-5 plex are unusable (such as because they have their NODEVICE flag set), the volume is unusable and cannot be overridden.

Once any parity resynchronization has been completed, any subdisks still marked as stale are recovered. This is done by marking the subdisk as stale and write-only and issuing VOL_R5_RECOVER ioctls to regenerate the data on the stale subdisks. The subdisk is then marked as non-stale and read-write.

If the -o delayrecover option is specified, the only recoveries that are performed are log replays. If the volume requires a parity resynchronization, it is enabled and left in the NEEDSYNC operation, and its parity is marked as stale. Any subdisk recoveries that are needed are not performed, and the stale subdisks are marked as stale.

Normally, if a volume has no RAID-5 logs, it is not enabled with a stale subdisk or an unusable subdisk. This is because a system crash or power failure while the volume is in use can make the parity stale and render the volume unusable. This behavior can be overridden by specifying the -o unsafe option, which enables the volume during the above situations.

Caution: Using the -o unsafe option can potentially result in data loss.

If only the -o delayrecover option is specified to start a volume with a stale subdisk or an unusable subdisk, the start operation fails. In this case, the delayrecover option can be ignored by also specifying the -o syncstartok option.

stop

Stopping a raid5 volume disables the volume and its associated plexes. If the volume is in the SYNC state, it is changed to the NEEDSYNC state so that recovery is performed at the next start. Any invalid or detached RAID-5 logs are set to the BADLOG state so that they are not used during the next start.

Normally, the stop operation fails if any extended operations are using the volume or any of its plexes. Such operations are detected as a non-empty value for the tutil0 field in a volume or plex record. If the -f option is specified, then the stop operation ignores volume and plex tutil0 fields.

FILES

/usr/lib/vxvm/type/usetype/vxvol

The utility that performs volume operations for a particular volume usage type.

/dev/vx/dsk/group/volume

The device node that can be used for mounting a file system created on the volume named volume in the disk group named group.

/dev/vx/rdsk/group/volume

The device node that can be used for issuing raw I/O requests and also for issuing ioctl requests to the volume named volume in disk group named group.

EXIT CODES

The vxvol utility exits with a non-zero status if the attempted operation fails. A non-zero exit code is not a complete indicator of the problems encountered, but rather denotes the first condition that prevented further execution of the utility.

See vxintro(1M) for a list of standard exit codes.

SEE ALSO

vxassist (1M), vxdg (1M), vxinfo (1M), vxintro (1M), vxmend (1M), vxplex (1M), vxrecover (1M)