Active Directory

A directory service that implements LDAP in a Windows environment. It provides a hierarchical structure for organizing access to data.

aggregate (bonded) network interface

Virtual network interface that consists of real interfaces working in tandem. A virtual interface can provide the aggregated bandwidth of all of the interfaces that you used to create it.


Challenge Handshake Authentication Protocol is a means of authentication used between a client and server where the password is sent over the wire in a form that is impossible to discover and impossible to replay. Both client and server must know what the original password is, but someone snooping on wire traffic cannot recover the password and cannot later send the original (snooped upon) authentication packet to the server in an attempt to try to trick it into letting them authenticate as a valid client.


Common internet filesystem. This protocol is usually used by Microsoft Windows clients.


Computer running a program that accesses the fileserver.

current metric

Metric drawn live from the server or taken from the last few minutes of the metric archives.


Disk cache manager, which lets you configure the DMF disk MSP to manage data on secondary storage, allowing you to further migrate the data to tape as needed.

default network gateway

The IP address of the router that this system should use to communicate with machines that are outside of its subnet.


Dynamic host configuration protocol (DHCP) allows one or more server systems to dynamically distribute network IP addresses and site configuration parameters to new or requesting client systems. By using DHCP, a site with only a few available addresses can serve a large number of hosts that connect to the network only occasionally, or a large site can manage the permanent assignment of addresses with a minimum of administrative attention. The NAS server can be configured as a DHCP client.

directory service

See name service.

distinguished name

A unique identifier for an entry in an LDAP directory tree structure.

disk IOPS

Disk I/O per second.

disk striping

Writing data in units to multiple disks in a round-robin fashion, increasing IOPS performance.

disk throughput

The amount of data that is transferred to and from disks.

dual-resident file

In DCM, a cache-resident copy of a migrated file that has already been copied to tape, and can therefore be released quickly in order to prevent the cache filling, without any need to first copy it to tape


Fibre Channel storage interface connection.


Fully qualified domain name.

hot spare

Disk drive within a RAID array that is not used unless another drive within the RAID array fails, at which point it is added to the filesystem to replace the failed drive without shutting the filesystem down or interrupting service.

historic metric

Metric taken exclusively from the metric archives.

idle time

Time that remained when the CPU could not find any tasks to run


The client accessing the storage in an iSCSI network.

interrupt time

Time the CPU spent processing requests from I/O devices. In a fileserver context, these are almost exclusively generated by disk operations or network packets and by switching between processes.


I/O per second.


Internet Small Computers Systems Interface is a protocol that is used to transport SCSI commands across a TCP/IP network. This allows a system to access storage across a network just as if the system were accessing a local physical disk. In an iSCSI network, the client access the storage is called the initiator. The remote storage that the client accesses is called the target .


Lightweight directory access protocol (LDAP) is a networking protocol that organizes access to data in a directory tree structure.

name service

Application that manages the information associated with network users.


Network interface card.


Network information service (NIS) is a network lookup service that provides a centralized database of information about the network to systems participating in the service.


Network file system.

non-dual-resident file

A file in DCM that is not a cache-resident copy of a migrated file. It must be migrated to tape before it can be removed.


Network Time Protocol.

physical volume element

The combination of multiple RAID disk drives into a single logical unit.


Redundant array of independent disks.


A level of RAID that uses block-level striping and distributed parity

remote replication

Duplication of local filesystem writes on a separate machine. The local system is the replication source, the system on which the writes are duplicated is the replication destination.


A finite capacity of the fileserver.

serial ATA (SATA)

Serial advanced technology attachement storage interface connection.


Task performed by the fileserver.

shadow file

A file that is protected from all access by non- root users and stores the encrypted passwords

smart host

The gateway server where email should be delivered.


Virtual point-in-time image of a filesystem. Snapshot copies are not actual media backup for a filesystem.

system time

Time the CPU spent executing kernel code. This is usually dominated by NFS file serving and accessing data from disks.

tape library slot usage

The number of slots used by DMF, other applications, or vacant.


The storage that appears to the initiator as a disk drive in an iSCSI network.


Tape Management Facility.


Volume group, one of the components of a DMF library server. A volume group is responsible for copying data blocks onto alternate media.

wait time

Time when a CPU was forced to do nothing while waiting for an event to occur. Typical causes of wait time are filesystem I/O and memory swapping.


An operating system setup and configuration tool.