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HiCommand Dynamic Link Manager User's Guide (for Windows(R))
This glossary explains the terms used in this manual.
A
- automatic failback
- Functionality for checking the status of paths at regular intervals, and automatically placing the status of a path recovered from an error into Online status.
- If a path with Offline(E) or Online(E) status recovers from an error, automatic failback places the path Online.
- Automatic failback checks the status of paths that were placed in Offline(E) or Online(E) status because of an error, but does not check the status of paths that were placed in Offline(C) status by executing the offline operation. For details on the offline operation, see 7.4 offline (Places a path or paths offline).
- AutoPATH_ID
- An ID that HDLM assigns to a path at system startup. Every path has a unique AutoPATH_ID.
- (See also: path)
B
- boot disk environment
- An environment in which the startup disk is in a storage subsystem instead of in the host.
C
- CHA (Channel Adapter)
- An adapter for controlling a channel of a storage subsystem.
- CLPR(Cache Logical Partition)
- A function, supported by the TagmaStore USP and Universal Storage Platform V, for logically splitting a cache. This function splits the cache by array groups in the storage subsystem, so that other array groups do not affect cache performance.
- cluster
- A system that connects multiple hosts having the same OS or platform (that is, an environment in which the same application can run) and treats them as one system.
D
- Dev
- A logical division of an LU that HDLM controls and operates. A Dev is equivalent to a partition in Windows.
- In a Windows, each LU has only one Dev.
- Each Dev has a Dev number.
- (See also: Dev number)
- Dev number
- A Dev number (DNum column) in the configuration list in HDLM.
- 0 is displayed. This number indicates the entire LU.
- HDLM operates assuming that one LU has one Dev, so the Dev number is fixed to 0
- (See also: Dev)
- dynamic reconfiguration
- Dynamic reconfiguration enables HDLM to recognize devices whose configuration has been changed without restarting the host. The plug and play operation of Windows enables this functionality.
E
- emulation type
- An LU type accessible from a host. Since an HDLM host is an open-system host such as a PC or a UNIX machine, the HDLM host can access only the LUs that have open-system emulation types.
- For details on emulation types supported by a storage subsystem, see the maintenance manual for that storage subsystem.
F
- failback
- Functionality for placing the status of a path recovered from an error into Online status, and switching the access path to the recovered path.
- failover
- Functionality for switching to another normal path if there is an error in a path, thereby enabling the system to continue to operate.
- FC-SAN (Fibre Channel - Storage Area Network)
- A SAN using a fibre channel.
H
- HBA (Host Bus Adapter)
- A device that functions as an interface connecting hosts and external devices.
- In this manual, the term HBA indicates an interface card that is mounted on a host when the host connects to a storage subsystem via a SCSI or FC connection.
- HDLM alert driver
- A program that receives information about an error detected by the HDLM driver, and then reports the error information to the HDLM manager.
- HDLM driver
- A program that controls the HDLM functionality, manages paths, and detects errors.
- HDLM manager
- A program that manages error information. The HDLM manager receives the error information from the HDLM alert driver and then collects error logs.
- host
- A generic term for both servers and clients.
- host device
- A device within a host LU.
- (See also: host LU, host device name)
- host device name
- A logical area within a host LU.
- (See also: host device)
- host LU
- An LU that the host recognizes. The actual HDev entity is a Dev in the storage subsystem.
- Each host LU has a host LU number.
- (See also: LU, host LU number, host device)
- host LU number
- A number assigned to a host LU. The host LU number is a part of a path name.
- (See also: host LU, path name)
I
- intermittent error
- An error that occurs irregularly due to reasons such as a loose cable connection.
- IP-SAN (Internet Protocol - Storage Area Network)
- A data transfer network that connects hosts and storage subsystems by using the iSCSI standard.
L
- LDEV (Logical Device)
- The value that identifies an LDEV consists of a combination of the storage subsystem's product name, serial number, and internal LU. HDLM uses this value to identify an LU.
- load balancing
- Functionality for distributing the load across the paths that access each logical area within an LU. To distribute loads, load balancing uses multiple paths to perform I/O operations.
- Two types of algorithms are available: round-robin and extended round-robin.
- LU (Logical Unit)
- A logical unit that is a logical volume defined in the storage subsystem, and with which the host can perform input or output operations.
N
- node
- A server of cluster members.
- non-owner controller
- A controller other than an owner controller.
- Non-owner controllers exist only when the Thunder 9200, Thunder 9500V Series, or TagmaStore AMS/WMS series is in use.
- (See also: owner controller, non-owner path)
- non-owner path
- A path that passes through a controller other than an owner controller.
- Non-owner paths exist only when the Thunder9200, Thunder 9500V Series, or TagmaStore AMS/WMS series is in use.
- (See also: owner path, non-owner controller)
O
- owner controller
- A controller that has been set as an owner controller for an LU on the storage subsystem when using the Thunder 9200, Thunder 9500V Series, or TagmaStore AMS/WMS series. A controller other than an owner controller is called a non-owner controller.
- When using Lightning 9900 Series, Lightning 9900V Series, TagmaStore USP, or Universal Storage Platform V all controllers are owner controllers.
- (See also: owner path, non-owner controller)
- owner path
- A path that passes through a controller that has been set as an owner controller for an LU on the storage subsystem when using the Thunder 9200, Thunder 9500V Series, or TagmaStore AMS/WMS series. A path that passes through a controller other than an owner controller is called a non-owner path.
- When using the Lightning 9900 Series, Lightning 9900V Series, TagmaStore USP, or Universal Storage Platform V, all paths are owner paths.
- (See also: owner controller, non-owner path)
P
- path
- An access path from a host to storage subsystem. Access to a logical area within an LU in a storage subsystem is made via a cable connecting the host bus adapter on the host and the channel adapter on the storage subsystem. Each path has an AutoPATH_ID.
- (See also: AutoPATH_ID)
- path health checking
- Functionality for checking the status of paths at regular intervals.
- When an error occurs at a path that was in the Online status, path health checking changes the status of the path to the Offline(E) status.
- Path health checking checks only those paths that have Online status.
- path name
- The name consisting of the following four elements, separated by periods:
- Host port number (hexadecimal number)
- Bus number (hexadecimal number)
- Target ID (hexadecimal number)
- Host LU number (hexadecimal number)
- A path name is used to identify a path.
- (See also: host LU number)
- persistent reservation
- Similar to reservation, persistent reservation enables a host to declare that it has exclusive use of an LU, and prevents other hosts from accessing that LU. Note, however, that reservation allows a host to have exclusive use of only one path to the LU, but persistent reservation allows a host to have exclusive use of more than one path.
- If HDLM applies persistent reservation, a host can have exclusive use of multiple paths to an LU, so load balancing among these exclusively used paths is possible.
- (See also: reservation)
R
- Remove LU
- Functionality to delete LU from an HDLM target host when an LU is deleted or all paths connected to the LU are placed in Offline(E) status.(the LU dynamic deletion functionality)
- reservation
- The reservation functionality enables a host to declare that it has exclusive use of an LU, and prevents other hosts from accessing that LU. Access permission for an LU that has been reserved is given only to the host that issued the reservation, so the LU cannot be accessed from multiple paths simultaneously. As a result, load balancing is not possible.
- (See also: persistent reservation)
S
- SAN (Storage Area Network)
- A high-speed network connecting hosts and storage subsystems. This network is independent of a LAN and is dedicated to data transfer. A SAN provides faster accesses to storage subsystems, and prevents the transfer of high-volumes of data from deteriorating LAN performance.
- SCSI device
- A SCSI disk device
- SLPR(Storage Logical Partition)
- A function, supported by the TagmaStore USP, and Universal Storage Platform V, for logically splitting a storage subsystem. This function splits the resources (ports, CLPR, and volumes) in the storage subsystem, so that the user can manage each resource independently.
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