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drdmgr(8)
NAME
drdmgr - Gets or sets distributed device attributes
SYNOPSIS
Query:
/usr/sbin/drdmgr [-n] [-h member] [-a attribute]... [-v] [-F raw | std]
device [device ...]
Set:
/usr/sbin/drdmgr [-h member] [-a attribute=value]... [-v] device
Get version number:
/usr/sbin/drdmgr -V
OPTIONS
-n Gets attribute values without waiting for reconfiguration to
complete. If a reconfiguration is in progress at the time a
drdmgr query occurs, and the -n flag is specified, the current
attribute values are returned. If the -n flag is not specified,
drdmgr waits until reconfiguration is complete before getting the
attribute values.
This flag is valid only when getting attributes.
-h member Designates the member that the command acts on. The default is
the local member. A member name takes the same form as the
output from a hostname -s command.
Regardless of which member drdmgr acts on, the SERVER and
PARTITIONS device attributes are cluster-wide and have the same
values on every member. The ACCESSNODE and STATISTICS attributes
are specific to each member, and can vary according to the member
drdmgr acts on.
The default value for -h is the local member.
-a attribute
-a attribute=value
Specifies the attribute to be queried or set. If you do not
specify an attribute, all attributes for the device are
displayed. If you specify an attribute but no value, the current
value for that attribute is displayed. If you specify an
attribute followed by =value, drdmgr sets the attribute to the
specified value. When setting attributes, you can specify only a
single device.
The following are valid attributes. Attribute names are not case
sensitive, and any attribute can be preceded by DRD_. For
example, server, SERVER, and DRD_SERVER are all synonyms.
SERVER The member or members that serve a device. Except
during relocations, the value of this attribute is the
same for all members.
When you query this attribute, drdmgr displays a list
of members that can act as servers of the device and
lists those members that actually serve the device. If
the device is a direct-access I/O disk, then all
cluster members with local access to the disk are
listed as servers. If the device is a served disk or
tape, then the name of the one cluster member that
serves the device is displayed.
Setting the SERVER attribute for a served disk or tape
causes a planned relocation to be performed. Only one
member can be specified when setting the attribute.
That host becomes the one cluster member that serves
the device. Setting this attribute on a direct-access
I/O disk fails unless the disk is already a served
disk. If the value of the SERVER attribute specified
in the drdmgr command is the same as the current value,
no relocation occurs. Unexpected behavior can result
if you set the SERVER attribute and specify a direct-
access I/O disk.
ACCESSNODE
The member used by a client member when it accesses a
specific device. This attribute applies to client
members and is member-specific. It is useful for load-
balancing access to direct-access I/O disks.
When you query this attribute, drdmgr displays the name
of the member used by the client member when it
accesses the device. For a served disk or tape, this
is the same as the value of the SERVER attribute; the
server and the access member are the same. For a
direct-access I/O disk, the value of the ACCESSNODE
attribute is the member from which the disk is accessed
by an application running on the client member. For a
direct-access I/O disk, the default value of the
ACCESSNODE attribute is the local member, but it can be
any member capable of serving the disk.
When you assign a value to the ACCESSNODE attribute,
device traffic is redirected to the indicated member.
If you attempt to set the ACCESSNODE attribute to a
member that is not currently a server for the device,
drdmgr returns an error.
If the SERVER attribute for a served device is set, the
ACCESSNODE attribute for that device is automatically
set to the same value.
If an automatic failover occurs because of a member or
path failure, the ACCESSNODE attribute is changed. When
the original path becomes available again, you must
reset the attribute to the pre-failover value in order
to return to using the pre-failover member.
STATISTICS
When you query this attribute, drdmgr displays
cluster-related I/O statistics about the device: the
number of read operations, the number of write
operations, the number of bytes read, and the number of
bytes written.
The STATISTICS attribute is member specific. When this
attribute is queried from a client member, drdmgr
displays statistics about the remote I/O. When this
attribute is queried from a server member, drdmgr
displays statistics about device I/O for both clients
and the server.
Setting the STATISTICS attribute to 0 (zero) resets the
statistics counters to 0. Zero is the only value the
user can assign to STATISTICS.
PARTITIONS
When you query this attribute, drdmgr displays a bit
mask in hexadecimal of the open disk partitions and
explicitly identifies the open partitions. This
information is useful if you are considering
repartitioning a disk.
The drdmgr command checks all the members that use this
disk, to see whether any of the members has open
partitions on the disk. PARTITIONS is the result of a
logical OR of the open partition mask for each member
that uses the disk.
The PARTITIONS attribute cannot be set.
-v Enables verbose mode.
device [device ...]
A device name that identifies the device upon which the specified
operations are executed. Note that /dev/rdisk/dsk8c, dsk8b, and
dsk8 all refer to the same disk. Similarly, /dev/tape/tape0c and
tape0c refer to the same tape drive.
For queries where more than one device is named, the requested
information is returned for each device. Use a wildcard to get
information for all the disks in a given directory. To avoid
querying each disk multiple times, specify a partition in the
wildcard. For example, /dev/rdisk/*a
When setting an attribute, you can specify only a single device.
-V Returns the version of the command.
-F std | raw
Specifies output format. The default, std, is intended to be read
by people. The output is clearly labeled and formated for that
purpose.
The raw output is intended to be used as input to scripts. Data
is unlabeled. Data fields are separated by spaces. Data is
grouped into lines as follows:
Line 1, data about member on which the command was executed:
Member name.
Member number.
The date (year month day hour minute second).
For example:
mutt 2 1998 12 08 09 12 50
Line 2, device data:
Device name.
Hardware ID.
Device type: 1=direct-access I/O device, 2=served
device, 0=unknown.
Device kind: 1=disk, 2=tape, 3=changer device,
0=unknown.
Result of test for access member name: T=name found,
F=name not found.
Access member name (if previous field is T) or none (if
previous field is F). For information about the access
member, see the description of the ACCESSNODE
attribute.
Device status: 1=OK, 2=no service found for device,
3=cluster reconfiguration in progress, 4=not a cluster
device, 0=status unknown.
Open partitions on the device. The number is a hex
bitmap of open partitions on the disk, with the h
partition at the high bit and the a partition at the
low bit. For example, 0x80 indicates that only the h
partition is open. 0x1 indicates only the a partition
is open. 0xff indicates all partitions are open.
Total number of servers.
Number of lines of member statistics that will be
generated.
For example,
dsk2 24 1 1 T mutt 1 0x3 2 1
Data about possible servers of the device. One line per member:
S (Indicates data is for a server.)
Member name.
Member number.
Status: 1=not a server, 2=server, 0=unknown. Although
a served device might be attached to several members,
it is served by only a single member at a time. The
serving member can be changed to any available server.
For example,
S jeff 1 2
The last line shows the I/O data for the client.
This data is for I/O activity is through the member on
which the drdmgr command was executed (by default, the
local member; otherwise, the member designated with the
-h option):
C (Indicates data is for a client).
Member number.
Client name.
Status of client-to-server connection. A=active. The
client member is currently using the member on which
the drdmgr command executed as the server for this
device. I=inactive. The client member is not
currently using the member on which the drdmgr command
executed as the server for this device. This value can
also indicate that the client node is not currently a
member of the cluster. U=unknown. The client status
could not be determined.
Total number of read operations.
Total number of bytes read.
Total number of write operations.
Total number of bytes written.
For example,
C 2 jeff I 392 26468352 3113 26058752
DESCRIPTION
Use the form in the first syntax diagram to query DRD (device request
dispatcher) attributes. Use the second form to set DRD attributes. The
third form returns the version number of drdmgr.
In a cluster, DRD handles the distribution of disk and tape requests.
Disks can be either served or direct-access I/O. Tapes are always served.
Use drdmgr with the SERVER attribute to specify or query which members
actually serve a particular file system/disk or tape.
With a served device, only one member is allowed to act as server of the
device, even though the device might be physically attached to several
members. When a served device is connected to a shared bus, you can use the
SERVER attribute to designate which member on the shared bus serves the
device.
A direct-access I/O disk attached to a shared bus is served by all members
on that bus, and you cannot set the SERVER attribute for the disk.
Use drdmgr with the ACCESSNODE attribute to specify or query which member
is used by the client member to access a device to which the client member
is not directly connected.
Setting the ACCESSNODE attribute applies only when the device is not local
to the member on which you execute the command, and the disk is a direct-
access I/O disk on a shared bus. In this case, you can set the accessnode
to be any one of the members on the shared bus.
The accessnode for a member and a direct-access I/O device when both are
attached to the same shared bus is the member itself, and you cannot change
the accessnode.
The accessnode to a served device is always the same as the server for the
device.
The values of attributes set with drdmgr do not survive a reboot of the
host on which the attribute was set.
To set an attribute and have it survive a reboot, create a startup script
that calls drdmgr to make the desired configuration.
EXAMPLES
1. In the following example, drdmgr is used to get the values of all the
distributed device attributes for dsk11:
# drdmgr dsk11
View of Data from Node mutt.tyron.com as of 1998-12-07:11:45:44
Device Name: dsk11
Device Type: MUNSA Disk
Device Status: OK
Number of Servers: 2
Server Name: mutt
Server State: Server
Server Name: jeff
Server State: Server
Access Node Name: mutt
Open Partition Mask: 0x3 < a b >
Statistics for Client Node: mutt.cntrl.tyron.com
Number of Read Operations: 1565
Number of Write Operations: 3769
Number of Bytes Read: 8376320
Number of Bytes Written: 31883264
2. In the following example, drdmgr is used to check which partitions are
open on dsk3:
# drdmgr -a ACCESSNODE -a PARTITIONS dsk3
View of Data from Node mutt.tyron.com as of 1998-12-07:13:00:19
Device Name: dsk3
Access Node Name: mutt
Open Partition Mask: 0x3 < a b >
EXIT VALUES
Upon successful completion the command returns 0 (zero); otherwise it
returns a nonzero value.
FILES
/usr/sbin/drdmgr
The command path.
SEE ALSO
Commands: cfsmgr(8)
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Index for
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Alphabetical
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