The ability to support I/O interspersed on multiple paths to a storage device.
The ability to support I/O on a path to a storage device with an alternate path for failover.
Hardware that allows one device to interact with another. Typically, an adapter enables a computer to access peripheral devices or networks. In common SAN architecture, the host bus adapter (HBA) or network interface card (NIC) enables connection to the SAN.
An alternate name for an entity that is easy to identify.
Amount of physical space in the pool that is in use by virtual disks.
Each mirrored virtual disk has a preferred server and an alternate server. Generally, the alternate server is used for failover when the preferred server is not available.
Asymmetric logical unit access occurs when the access characteristics of one port may differ from those of another port. ALUA enables support for SCSI-3 target port group commands.
Advanced Site Recovery, also known as Bidirectional Replication.
Authentication is the process by which the system validates the logon information of a user. A user name and password are compared against an authorized list, and if the system detects a match, access is granted to the extent specified in the permission list for that user.
Back-end refers to the physical disks that are connected to storage servers and used for storage. This term can also be used to describe the paths between storage servers and physical disks.
The volume that contains the Windows operating system and support files.
The main communication avenue in a computer; an electrical pathway along which signals are sent from one part of the computer to another, for example from the CPU to the hard disk.
Random access memory used for temporary storage of information. Retrieval of data from cache memory is much faster than getting it directly from disk. Increasing cache improves performance.
Continuous Data Protection is a disaster recovery solution for virtual disks.
The basic level of security based on the Challenge Handshake Authentication Protocol (CHAP). CHAP is a protocol that is used to authenticate the peer of a connection and is based upon the peers sharing a secret.
A security key similar to a password.
Command line interface, used for snapshots, replication, and support bundles. Commands initiated from a Windows command line instead of a user interface.
A group of independent computers that work together to perform a common set of services and present a single-system image to hosts. The use of a cluster enhances the availability of the services and scalability and managibility of the operating system providing the services.
The storage server with SANsymphony software installed.
The delta map is a record of the differences between the original virtual disk and the snapshot.
An arrangement of two or more disk drives with control software. May be in RAID or daisy-chain (linked in one after the other) fashion. The control software presents the disks' storage capacity to hosts as one or more virtual disks.
Domain Name Service. A computer program that converts between IP addresses and symbolic names for nodes on a network in a standard way. Most operating systems include a version of Domain Name Service.
The server running the Domain Name Service (DNS). DNS converts the IP addresses and symbolic names for nodes on a network.
Restoration of a failed system component's share of a load to a replacement component. Also, the process of moving resources, either individually or in a group, back to their preferred path after the path has failed and come back online.
The automatic substitution of a functionally equivalent system component for a failed one.
The ability of a system to continue to perform its function (possibly at a reduced performance level) when one or more of its components has failed. Fault tolerance in disk subsystems is often achieved by including redundant instances of components whose failure would make the system inoperable, coupled with facilities that allow the redundant components to assume the function of the failed ones. Fault tolerant features include mirroring, RAID-5 volumes, and server clusters.
A high speed network transmission technology that is capable of transferring data between two ports at up to 100 megabytes/second (higher speeds in the future) over a distance of up to 10 kilometers. It is almost three times as fast as the average physical SCSI connection. Largely credited with enabling the SAN model due to its performance attributes. Fibre Channel supports point to point, arbitrated loop, and switched topologies.
A high speed network transmission technology that is capable of transferring data between two ports at up to 100 megabytes/second (higher speeds in the future) over a distance of up to 10 kilometers. It is almost three times as fast as the average physical SCSI connection. Largely credited with enabling the SAN model due to its performance attributes. Fibre Channel supports point to point, arbitrated loop, and switched topologies.
Fully qualified domain name. The FQDN specifies the exact network location of the network device. For example, given a device with a local hostname \"mycomputer\" and a parent domain name \"mycompany.com\", the fully qualified domain name is \"mycomputer.mycompany.com\".
SAUs are free when they have been reclaimed and are available for use in a virtual disk.
Front-end is used to describe the host or storage client. This term can also be used to describe the paths between storage server and host.
GUID Partition Table. This is a physical disk initialization layout supported by Windows Disk Management utility.
A concept used to perform commands and functions on multiple objects simultaneously, i.e. a group of virtual volumes, snapshot relationships, or AIM sets.
High Availability. The ability of a system to function without interruption for a significantly longer period of time, with greater reliability than its individual components are capable. High availability is most often achieved through fault tolerance.
Host bus adapter.
The ability of a system to function without interruption for a significantly longer period of time, with greater reliability than its individual components are capable. High availability is most often achieved through fault tolerance.
A server that utilizes storage (virtual disks) served by a DataCore Server. Hosts can be any physical or virtual server with FC and/or iSCSI network capabilities. SANsymphony software supports hosts using all major open systems operating environments, including Windows, IBM AIX, Linux, VMware ESX, Citrix XenServer, HP HP-UX, and Oracle Solaris. (Also known as an application server or storage client.)
A hardware card that resides on the computer's bus and provides a connection to storage devices.
The computer that originates a SCSI I/O command over a network. Initiators are commonly storage clients in a SAN, but would also be storage servers if mirroring data.
A unique address that devices use in order to identify and communicate with each other on a network utilizing the Internet Protocol standard (IP)?a computer address. Any participating network device (i.e. routers, computers, servers, printers) can have their own unique address.
A network protocol standard, allowing for use of the SCSI protocol over TCP/IP networks. Building iSCSI-based Storage Area Networks (SANs) has become a less costly but worthy alternative to creating Fibre Channel-based SANs.
IP security (IPsec) is a protocol that enforces authentication and data encryption at the IP packet layer, which provides an added level of security.
iSCSI Qualified Name is the iSCSI node name used for identity. Similar to a MAC address.
An iSCSI Simple Name Services (iSNS) server groups initiators and targets in sets and allows automatic discovery of all target ports. iSCSI initiators and targets register with the iSNS server. Similar to DNS.
Originally used to mean a collection of disks without the coordinated control provided by control software; today the term JBOD most often refers to a cabinet of disks whether or not software control is present.
Originally used to mean a collection of disks without the coordinated control provided by control software; today the term JBOD most often refers to a cabinet of disks whether or not software control is present.
A network covering a local area, such as an office or group of buildings. Each computer or node in the LAN has its own computing power, but it can also access other devices on the LAN subject to the permissions it has been allowed (including data, devices, and the ability to communicate with other users in the network).
Loop Initialization Primitive (LIP) is a Fibre Channel (FC) primitive (low level command) used to initiate a procedure that results in unique addressing for all nodes.
A network covering a local area, such as an office or group of buildings. Each computer or node in the LAN has its own computing power, but it can also access other devices on the LAN subject to the permissions it has been allowed (including data, devices, and the ability to communicate with other users in the network).
SANsymphony software provides virtual Fibre Channel ports, called loopback ports, on each server. Loopback ports ares used exclusively to serve a virtual disk from the server to itself. This could be helpful during testing or troubleshooting virtual disk issues. For instance, a virtual disk served to a host can also be served to the loopback port in order to read the contents.
Logical Unit Number is a logical array of storage units. A storage client discovers a LUN when a virtual disk is served.
Assigning paths to LUNs maintaining a balance between the resources assigned to each available path.
A method of achieving high availability (HA) by providing redundant paths to target SCSI devices. Multiple instances of a disk device object identified by the driver over one or more fibre channel paths will be managed as one object with multiple paths. Only one device will be exposed to the upper layer drives.
Master Boot Record. This is a physical disk initialization layout supported by Windows Disk Management utility.
The process or practice of continuously updating in real-time to make two or more identical copies of data on separate storage devices with the purpose of protecting data resources and maintaining business operations in the event of failure of the storage devices or the path between servers and storage devices.
Multipath I/O
Millisecond-a 1/1000th of a second.
Providing more than one physical path from the client to the virtual disk.
A network card (hardware) designed to allow computers to communicate over an Ethernet network using iSCSI.
A network card (hardware) designed to allow computers to communicate over an Ethernet network using iSCSI.
Network Time Protocol
Objects are resources managed by SANsymphony software. Objects include DataCore Servers, hosts, ports and I/O paths, physical disks, disk pools, and virtual disks,
If the total size of all virtual disks created from the pool is greater than the size of the pool, the difference is the amount over subscription.
Hard disk drive partitioning is the creation of logical divisions upon a hard disk that allows the application of operating system-specific logical formatting. Partitioning a hard drive makes it appear to be more than one hard drive, because each partition can be formatted for different operating systems, and files can be copied from partition to partition.
A path is a Fibre Channel or iSCSI connection between two ports.
petabyte
Any storage device that is qualified to work with the Windows operating system; from JBOD (just a bunch of disks) enclosures to intelligent storage arrays can be attached to a DataCore Server. Devices can connect through FC or iSCSI switches or directly to the storage server. Basic vendor-specific configuration and installation of these storage devices should be performed according to manufacturer instructions. After the physical devices are discovered by SANsymphony software, no further device-specific configuration is necessary, other than for hardware maintenance or failure correction. Disks marked as \"Removable\" in Windows Disk Management cannot be used as storage resources.
A port is a Fibre Channel or iSCSI port on the storage client or storage server. Ports are the end-points of paths.
When multiple paths exist from the client to the virtual disk, the preferred path is the path to use until a failure occurs. During a failure, another path will take over.
The preferred server is the first server selected as a storage source when the virtual disk was created. If the virtual disk is mirrored, then the additional storage source is from the alternate server.
A Raw Device Mapping (RDM) is a mapping file in a VMFS volume that acts as a proxy for a raw physical storage device. The RDM allows a virtual machine to directly access and use a VMFS volume as a storage device.
Reclamation is the process of removing old data from the physical disk. Reclamation occurs when a disk is added to a pool or when a previously used virtual disk from a pool is deleted.
Two paths from the client to each server.
Space reserved (but not allocated) in a pool for exclusive use by a virtual disk.
The point-in-time used to create a rollback.
Network used exclusively for storage infrastructure.
This term is used in the context of the resources that SANsymphony software manages: storage servers, hosts, ports and I/O paths, physical disks, disk pools, and virtual disks. These resources are also referred to as objects.
A pre-set unit of measurement for a pool. When a virtual disk is created, SAUs are allocated from the pool.
A method of destroying the current contents of a disk by overwriting, as opposed to logically, erasing the contents.
Persistent Reserve refers to a set of Small Computer Systems Interface-3 (SCSI-3) standard commands and command options which provide SCSI initiators with the ability to establish, preempt, query, and reset a reservation policy with a specified target device.
An open storage interface designed for network computing, enabling simultaneous communication between multiple devices, subsystems, and local host processors throughout the open systems environment.
A collection of standards which define the way storage devices communicate with hosts. Originally intended primarily for use with small (desktop and desk-side workstation) computers, SCSI has been extended to serve most computing needs, and is arguably the most widely implemented I/O bus in use today.
Shared Multi-port Array
SMTP (Simple Mail Transfer Protocol) is the protocol used for outgoing email notifications in the software.
The point-in-time that a snapshot was created or updated.
A full usable image of a defined collection of data created at a specific point in time. You can use this image for application testing, backups, or in other situations where you could benefit from using a collection of data as it appeared at a previous point in time.
Simple Network Management Protocol (SNMP) is a popular protocol for network management.
Secure Sockets Layer is a secure communications protocol used with TCP.
Network used exclusively for storage infrastructure.
Any storage device that is qualified to work with the Windows operating system; from JBOD (just a bunch of disks) enclosures to intelligent storage arrays can be attached to a DataCore Server. Devices can connect through FC or iSCSI switches or directly to the storage server. Basic vendor-specific configuration and installation of these storage devices should be performed according to manufacturer instructions. After the physical devices are discovered by SANsymphony software, no further device-specific configuration is necessary, other than for hardware maintenance or failure correction. Disks marked as \"Removable\" in Windows Disk Management cannot be used as storage resources.
A centralized resource of disk drives and disk subsystems connected by a Storage Area Network to application servers.
A storage server is a standard, commercially available Windows-based computer on which SANsymphony software has been installed. A storage server contains FC HBAs and/or NICs for iSCSI. A storage server has access and control over physical disk resources which are used to create virtual storage.
The source of the storage used to create a virtual disk. The source can be from a disk pool or a physical disk (referred to as a pass-through disk).
Units of storage (also referred to as chunks) that are allocated when virtual disks are created. Storage units are allocated dynamically from dynamic pools and allocated in total from static pools.
A network infrastructure component to which multiple nodes attach. Unlike hubs, switches maintain full bandwidth capacity to all attached devices. They also have the ability to rapidly switch node connections from one to another.
The computer that receives a SCSI I/O command. The storage device receiving read and write commands.
The Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet and most commercial networks run. The two protocols in it are: Transmission Control Protocol (TCP) and Internet Protocol (IP), the first two defined protocols.
The number of I/O requests satisfied per unit time. Expressed in I/O requests/second, where a request is an application request to a storage server to perform a read or write operation.
Third Party Logout (TPRLO) is a method of resetting storage target devices.
DataCore Management Console or other DataCore user interface included in the platform.
Uninterruptible Power Supply (UPS) is an electrical apparatus that provides emergency power to servers when the input power source fails.
Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. UTC is based on International Atomic Time (TAI).
Virtual disk paths consist of the front-end paths from server to clients and the mirror paths between servers.
The storage on one or two servers which comprise the virtual disk. A non-mirrored virtual disk will have one source and a mirrored virtual disk will have two sources, one from each server. (Known in earlier versions as logical disks.)
A storage resource that is made to look and behave like a complete disk volume to an operating system on a storage client, when the storage resource actually is the amount of space allocated from the pool, which may be as small as one storage allocation unit (SAU).
A virtual SAN configuration is created when SANsymphony software is installed on hosts to bring advanced SAN features closer to running applications. Hosts can virtualize local storage resources to take advantage of the same performance enhancing features used by DataCore Servers; such as auto-tiering and caching.
A computer network that covers a broad geographical area; a network that uses routers and public communication links. The largest and most well-known example of a WAN is the Internet.
Write operations are recorded in the cache first and an acknowledgement is immediately sent back to the operating system confirming the operation before the write operation is written to physical disk.
Writes sent to the virtual disk are not cached on the storage server, but are sent directly to physical disk for storage.
Every port on a fibre channel network has a unique 8-byte identifier called the WorldWide Name (WWN). This identifier is hard-coded into every fibre channel host busadapter (HBA), fibre channel disk drive, tape drive, and so forth, that is capableof participating on a fibre channel network. (The WWN is similar in concept to theMAC address in Ethernet cards.)
A method of subdividing a Storage Area Network into logical groups of nodes. Storage area network nodes outside a zone are invisible to nodes within the zone. Also, traffic within each zone may be physically isolated from traffic outside the zone