VDISK(1M) RISC/os Reference Manual VDISK(1M)
NAME
vdisk - configure virtual disk
SYNOPSIS
/etc/vdisk split add vdisk partition start end
/etc/vdisk split delete vdisk
/etc/vdisk split info [ partition]
/etc/vdisk span add [ -b partition ] [ -a partition ] vdisk
partition [ partition ...]
/etc/vdisk span delete vdisk partition [ partition ...]
/etc/vdisk span info
/etc/vdisk mirror add [ -b partition ] [ -a partition ]
vdisk partition [ partition ...]
/etc/vdisk mirror delete vdisk partition [ partition ...]
/etc/vdisk mirror info
/etc/vdisk stripe add [ -s stripe_size ] [ -b partition ] [
-a partition ] vdisk
partition[ partition ...]
/etc/vdisk stripe delete vdisk partition [ partition ...]
/etc/vdisk stripe info
/etc/vdisk attr get partition attr
/etc/vdisk attr set partition attr value
/etc/vdisk info [ partition]
DESCRIPTION
vdisk is used to create, delete, and examine virtual disks
(see vdisk(7)). It can also be used to modify the attri-
butes of an existing virtual disk.
The vdisk argument should be of the form vdcCdDsS. C, D,
and S are the major number, high order four bits of the
minor number, and low order four bits of the minor number,
respectively. If a new virtual disk is being created, you
must make a special device using MKDEV(see MKDEV(1M)). The
partition argument is the device name of a partition, of the
form iscCdDsS, ipcCdDsS, or vdcCdDsS.
The following types of requests are supported by the vdisk
command:
split Split a partition into a smaller virtual par-
tition.
span Concatenate multiple partitions together to
form one large partition.
mirror Replicate the data over multiple partitions.
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stripe Spread the data over several partitions in
stripesize blocks.
attr Examine or modify virtual disk attributes.
The legal attributes are described below.
info Display information on all the virtual disks.
The split, span, stripe, and mirror requests have the fol-
lowing options:
add Add a member to a virtual disk.
delete Remove a member from a virtual disk.
info List the virtual disks of the specified type.
When adding a span, stripe, or mirror partition, the follow-
ing control options are available:
-b partition
Add the new partition before partition in the set.
-a partition
Add the new partition after partition in the set.
-s stripesize
The value to use for the stripe blocksize.
Many of the partition attributes can be modified with the
attr request. The following attributes apply to all types
of virtual partitions:
open
The partition is currently open. If this
attribute is set after the system is booted,
the partition may have been in use when the
system went down and is possibly out of sync.
disabled The member partition has been disabled.
The following attribute pertains to striped partitions:
stripesize
The stripe block size for striped partitions. The
default is 16 (the file system block size).
The following attributes pertain to split partitions:
splitstart
The beginning block of a split partition.
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splitend
The ending block of a split partition.
The following attributes are for mirrored partitions only:
writesequential
Writes to the members of a mirrored partition
occur sequentially. This attribute is off by
default.
insync
The member partition is in sync with the primary
partition of the set.
readalgorithm
The algorithm to use when choosing which member of
the mirror set to read. The following are legal
read_algorithm values:
primary All reads are attempted on the primary
partition first. A read is only
attempted on the secondary partitions
when the read from the primary parti-
tions fails. This algorithm is particu-
larly useful when the primary partition
is on a faster device than the secondary
partitions. This is the default read
algorithm.
next Reads are distributed to different par-
titions in round-robin order. This
algorithm works best in the case of many
small random accesses.
burst This is similar to read next except that
several reads are done on one partition
before switching over to the next. The
burst size is dynamically configurable.
This algorithm works well with sequen-
tial access patterns.
balanced Each read is divided evenly among the
member partitions.
bursttotal
The burst size to use when doing mirror burst
reads. The default value is 5.
autosync
If this attribute is set and the open flag is set
(for example, after a crash), instead of marking
all the secondary partitions dirty, the system
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automatically starts a sync operation.
balancedminimum
The minimum I/O request size that causes the I/O
to be divided among the partitions. This attri-
bute is only used when the read algorithm is
balanced_read. The default value is 17.
dirty
This attribute is set when a member of the mirror
set may be inconsistent (e.g. when coming back up
after a crash). No access is permitted to a
member which has this attribute set.
syncblocksize
The blocksize to use when syncing a mirror set.
The default value is 256 blocks.
readerrorcount
The total number of read errors on a member parti-
tion of a mirror partition.
readerrorthreshold
The number of read errors permitted before a
member partition of a mirror set is disabled. The
default threshold is 50.
syncdelay
This is the delay time between sync operations.
The value is in 100ths of a second. The default
value is 0.
scratch
If this attribute is set, the partition is being
used for scratch (or temporary) storage. If a
system crash occurs while a scratch partition is
open, crash recovery is not initiated for the par-
tition when the system is rebooted.
syncinprogress
If the value is 1, a sync is in progress. If the
value is 0, there is no sync currently in pro-
gress. Changing the value from 0 to 1 initiates a
sync. Changing the value from 1 to 0 stops the
sync that is in progress.
synclocation
This attribute cannot be changed. It indicates
the current block number of the sync operation.
NOTES
Only the super-user may modify a virtual disk. After adding
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to or deleting from a spanned, split, or striped partition,
you must rebuild the file system using the newfs.ffs(1M)
command. You must also rebuild the file system after chang-
ing the attributes of a split or striped partition.
DIAGNOSTICS
INFORMATIONAL MESSAGES
The following messages provide information only (no errors
have occurred). They are displayed as a result of a change
in the attributes of a partition. The text in italics is
supplied by the system.
partition: marked partition as dirty.
partition: turning on sequential writes.
partition: turning off sequential writes.
partition: marking partition as not in sync.
partition: marking partition as disabled.
partition: marking partition as not disabled.
partition: marking as open.
partition: marking as not open.
partition: turning on mirror auto sync.
partition: turning off mirror auto sync.
partition: setting stripe size to number.
partition: setting read algorithm to primary.
partition: setting read algorithm to next.
partition: setting read algorithm to burst.
partition: setting read algorithm to balanced.
partition: setting burst total to number.
partition: setting balanced minimum to number.
partition: marking partition as dirty.
partition: marking partition as not dirty.
partition: setting sync_blocksize to number.
partition: setting read_error_count for partition to
number.
partition: setting read_error_threshold for partition
to number.
partition: setting split_start to number.
partition: setting split end to number.
partition: marking as not scratch.
partition: marking as scratch.
partition: setting sync delay to delay.
ERROR MESSAGES
Write Error Messages
The messages listed below are displayed if an error occurs
during an I/O operation on a virtual disk. The messages
appear in the syslog (see syslogd(8)) and give an indication
of the problem. The message also may appear on the console.
The text in italics is supplied by the system.
partition: received error error_number during write of
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partition. Member disabled.
Read Recovery Messages
The following error message indicates that a read error
occurred on a member of a mirrored partition and the system
is attempting to correct the problem:
partition: received error error_number during read of
partition. Attempting correction.
The following message indicates that the number of read
errors for the specified partition has exceeded the number
allowed. The partition is disabled.
partition: read error count of partition exceeds
threshold. Disabling member.
The following message indicates an internal error:
partition: Unable to find dktab for partition. Read
error recovery failed.
The following message indicates that the read error was
corrected:
partition: error correction of partition successful.
The following message indicates that the write to correct
the read error failed and the partition is disabled:
partition: read error recovery write failed for parti-
tion. Member disabled.
The following message indicates that the read that is per-
formed after rewriting the data that caused a read error
failed and the error could not be corrected.
partition: read of partition received error
error_number. Read error recovery failed.
The following messages indicate that the read error could
not be corrected:
partition: read error recovery of partition failed.
partition: received error error_number. Read error
recovery failed.
Sync Messages
The following error messages may occur during a sync opera-
tion on a mirror partition or as a result of initiating a
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sync operation:
partition: received error error_number during sync.
Sync failed.
partition: sync of partition successful.
partition: partition is already in sync.
partition: adding first disk to mirror set. partition
marked as in sync.
partition: marking partition as in sync.
partition: adding first disk to mirror set. partition
marked as in sync.
partition: all accessible member are currently in
sync.
partition: only one disk in mirror set. partition
marked as in sync.
partition: stopping sync operation.
Warning Messages
The following message indicates an error from low level rou-
tines:
partition: received error error_number.
The following message indicates that one member partition
has had fewer updates of its dktab entry than the others in
the set. If the virtual partition is not a mirrored parti-
tion, data may be lost.
partition: bad generation count. Disabling partition.
The following messages indicate a problem updating internal
data structures:
vdisk: vd is NULL.
vdisk: vdhead is NULL.
vdisk: device does not have a physical disk.
vdinit: vdidx is NULL.
This message indicates that a disk was removed and replaced
or was moved to another machine. Use dvhtool(1M) to delete
the dktab entry and then reboot the system.
vdinit: unique id for disk is not in the plurality of
the disks.
The following three messages indicate a problem with the
disk volume header:
vdisk: get config dev device dktab wrong magic.
vdisk: device disk has an invalid dktab checksum.
vdisk: dev device dktab wrong magic.
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The following message indicates that the system does not
have sufficient memory available:
vd_update_physical: Unable to allocate dkentry buffer.
The following message may occur during an update to the
dktab and may mean that the disk is bad:
dktab2_iodone: dev device received error error_number.
The following message indicates that a disk was removed and
replaced in a different location. Either replace the disk
in its previous location or use dvhtool(1M) to delete the
dktab entry in the volume directory of the volume header.
After deleting the entry, you must reboot the system.
vdisk: dktab device number disk_vh does not match dev-
ice disk_vh.
The following message indicates that the generation counts
have been reset to zero to avoid overflow:
vdisk: resetting generation counts.
Volume Header Error Messages
The following messages indicates a problem with the physical
device:
vdisk: get config dev device unable to read dktab.
Received error error_number.
vdisk: set vh failed.
dktab_update_start: Unable to get volume header for
device device.
The following message indicates that the volume header on
the disk is full and an entry cannot be made for the virtual
disk:
vdisk: dev device no empty directory entry.
The following messages indicate problems with the volume
header of the disk:
dktab1_iodone: Received error error_number.
dktab3_iodone: Received error error_number while updat-
ing volume header for device.
vdisk: Received error error_number while updating
volume header for partition.
vdisk: set vh received error error_number.
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FILES
/etc/vdisk_data mapping of major/minor number to
/dev/dsk entry name.
SEE ALSO
Data Manager Manual, Data Manager Plus Manual.
ORIGIN
Mips Computer Systems, Inc.
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