Abstract: A technique is provided for implementing online restriping of a volume in a storage area network. A first instance of the volume is instantiated at a first port of the fibre channel fabric for enabling I/O operations to be performed at the volume. While restriping operations are being performed at the volume, the first port is able to concurrently perform I/O operations at the volume.

Abstract: The Switch includes a port configured to receive a command frame when installed in a switching Fabric. The frame identifies a source device and a destination device in the Switching Fabric, a command, and a read/write flag which indicates if the identified source intends to exercise read-only or write access to the destination device. The Switch also includes a processor coupled to the port. The processor is configured to trap the frame and prevent it from reaching the defined destination device in the switching Fabric if both the source and destination devices are in a read-only zone and the flag indicates that the source intends to write to the destination device. In this manner, read-only zones can be implemented in the Switching Fabric.

Abstract: Disclosed is a a session modification mechanism for altering a data tapping process in a storage area network (SAN). In general, a data tapping mechanism is set up so that an appliance receives SAN data that is tapped from a particular SAN session. That is, the data tapping mechanism provides to a particular appliance a copy of the SAN data that is being written from a particular host to a particular storage device. The session modification mechanism allows the appliance to alter various aspects of the SAN session that is to be (or is being) tapped.

Abstract: A technique is provided for facilitating information management in a storage area network. The storage area network may utilize a fibre channel fabric which includes a plurality of ports. The storage area network may also comprise a first volume which includes a first mirror copy and a second mirror copy. The storage area network may further comprise a mirror consistency data structure adapted to store mirror consistency information. A mirror consistency check procedure is performed to determine whether data of the first mirror copy is consistent with data of the second mirror copy. According to one implementation, the mirror consistency check procedure may be implemented using the consistency information stored at the mirror consistency data structure.

Abstract: A technique is provided for implementing online mirroring of a volume in a storage area network. A first instance of the volume is instantiated at a first port of the fibre channel fabric for enabling I/O operations to be performed at the volume. One or more mirroring procedures may be performed at the volume. In at least one implementation, the first port is able to perform first I/O operations at the volume concurrently while the mirroring procedures are being performed at the first volume. In one implementation, the mirroring procedures may be implemented at a fabric switch of the storage area network. Additionally, in at least one implementation, multiple hosts may be provided with concurrent access to the volume during the mirroring operations without serializing the access to the volume.

Abstract: A technique is provided for implementing online mirroring of a volume in a storage area network. A first instance of the volume is instantiated at a first port of the fibre channel fabric for enabling I/O operations to be performed at the volume. One or more mirroring procedures may be performed at the volume. In at least one implementation, the first port is able to perform first I/O operations at the volume concurrently while the mirroring procedures are being performed at the first volume. In one implementation, the mirroring procedures may be implemented at a fabric switch of the storage area network. Additionally, in at least one implementation, multiple hosts may be provided with concurrent access to the volume during the mirroring operations without serializing the access to the volume.

Abstract: Disclosed are methods and apparatus for data tapping within a storage area network (SAN) and providing tapped data to a third party device, such as an appliance. In general, mechanisms are provided in a SAN to allow a data tap of data flowing between an initiator and a target. In one implementation, a data virtual target (DVT) in created in a network device to intercept data sent by a specific initiator to a specific logical unit of a specific target. The data or a copy of the data is sent to both the specific logical unit of the specific target and to an appliance. The data routing may be accomplished by use of a virtual initiator (VI), which is configured to send the data (or a copy of the data) to the specific target and the appliance. In a transparent mode of operations, the DVT has a same PWWN (port world wide name) and FCID (fibre channel identifier) as the specific target. In a first proxy mode of operation, the DVT has a different PWWN and FCID than the specific target.

Abstract: Disclosed is apparatus and methods for enabling an appliance to receive data being sent between any host of a host cluster to a specified storage device's logical unit (LUN) in a single stream or session. In one embodiment, a data virtual target is initially set up for a specified storage device LUN so that data written from a host to the specified storage device LUN is received by the DVT. An appliance then sends a session request to mirror data that is sent to the DVT (and specified storage device LUN) to a specified LUN of the appliance. The session request is not host specific. That is, data that is sent by any host to the DVT is mirrored to the same appliance LUN.

Abstract: A technique is provided for implementing online restriping of a volume in a storage area network. A first instance of the volume is instantiated at a first port of the fibre channel fabric for enabling I/O operations to be performed at the volume. While restriping operations are being performed at the volume, the first port is able to concurrently perform I/O operations at the volume.

Abstract: The present invention provides methods and devices for implementing a Low Latency Ethernet (“LLE”) solution, also referred to herein as a Data Center Ethernet (“DCE”) solution, which simplifies the connectivity of data centers and provides a high bandwidth, low latency network for carrying Ethernet and storage traffic. Some aspects of the invention involve transforming FC frames into a format suitable for transport on an Ethernet. Some preferred implementations of the invention implement multiple virtual lanes (“VLs”) in a single physical connection of a data center or similar network. Some VLs are “drop” VLs, with Ethernet-like behavior, and others are “no-drop” lanes with FC-like behavior. Some preferred implementations of the invention provide guaranteed bandwidth based on credits and VL. Active buffer management allows for both high reliability and low latency while using small frame buffers. Preferably, the rules for active buffer management are different for drop and no drop VLs.

Abstract: The present invention provides methods and devices for implementing a Low Latency Ethernet (“LLE”) solution, also referred to herein as a Data Center Ethernet (“DCE”) solution, which simplifies the connectivity of data centers and provides a high bandwidth, low latency network for carrying Ethernet and storage traffic. Some aspects of the invention involve transforming FC frames into a format suitable for transport on an Ethernet. Some preferred implementations of the invention implement multiple virtual lanes (“VLs”) in a single physical connection of a data center or similar network. Some VLs are “drop” VLs, with Ethernet-like behavior, and others are “no-drop” lanes with FC-like behavior. Some preferred implementations of the invention provide guaranteed bandwidth based on credits and VL. Active buffer management allows for both high reliability and low latency while using small frame buffers. Preferably, the rules for active buffer management are different for drop and no drop VLs.

Abstract: A scalable NAS file system and protocols for implementing CIFS thereon are disclosed. In certain embodiments, the protocols implement the CIFS protocol on a scalable file server architecture having one or more protocol termination nodes, one or more file server nodes, and one or more disk controller nodes. Among the features that may be specifically implemented are tree access, file access, user authentication, locking, state maintenance, and failover of protocol termination nodes and file server nodes.

Abstract: A method and apparatus to improve the performance of a SCSI write over a high latency network. The apparatus includes a first Switch close to the initiator in a first SAN and a second Switch close to the target in a second SAN. In various embodiments, the two Switches are border switches connecting their respective SANs to a relatively high latency network between the two SANs. In addition, the initiator can be either directly connected or indirectly connected to the first Switch in the first SAN. The target can also be either directly or indirectly connected to the second Switch in the second SAN. During operation, the method includes the first Switch sending Transfer Ready (Xfr_rdy) frame(s) based on buffer availability to the initiating Host in response to a SCSI Write command from the Host directed to the target. The first and second Switches then coordinate with one another by sending Transfer Ready commands to each other independent of the target's knowledge.

Abstract: A method and apparatus to improve the performance of a SCSI write over a high latency network. The apparatus includes a first Switch close to the initiator in a first SAN and a second Switch close to the target in a second SAN. In various embodiments, the two Switches are border switches connecting their respective SANs to a relatively high latency network between the two SANs. In addition, the initiator can be either directly connected or indirectly connected to the first Switch in the first SAN. The target can also be either directly or indirectly connected to the second Switch in the second SAN. During operation, the method includes the first Switch sending Transfer Ready (Xfr_rdy) frame(s) based on buffer availability to the initiating Host in response to a SCSI Write command from the Host directed to the target. The first and second Switches then coordinate with one another by sending Transfer Ready commands to each other independent of the target's knowledge.

Abstract: Methods and devices are provided for non-disruptive monitoring of network traffic through one or more ports of a Fibre Channel network device. Preferred embodiments of the invention are used in conjunction with the switched port analyzer (“SPAN”) and/or remote SPAN (“RSPAN”) features. SPAN mode operation allows traffic through any Fibre Channel interface of a network device to be replicated and delivered to a single port on the same network device. Ingress SPAN allows the monitoring of some or all packets that ingress a specified port or ports. Egress SPAN allows the monitoring of some or all packets that egress a specified port or ports. RSPAN allows the delivery of the replicated traffic to a port on a remote network device. Filtering may be applied, for example, to SPAN packets having selected virtual storage area network numbers.

Abstract: The Switch includes a port configured to receive a command frame when installed in a switching Fabric. The frame identifies a source device and a destination device in the Switching Fabric, a command, and a read/write flag which indicates if the identified source intends to exercise read-only or write access to the destination device. The Switch also includes a processor coupled to the port. The processor is configured to trap the frame and prevent it from reaching the defined destination device in the switching Fabric if both the source and destination devices are in a read-only zone and the flag indicates that the source intends to write to the destination device. In this manner, read-only zones can be implemented in the Switching Fabric.

Abstract: An Fibre Channel Switch which enables end devices in different Fabrics to communicate with one another while retaining their unique Fibre Channel Domain_IDs. The Switch is coupled to a first fabric having a first set of end devices and a second fabric having a second set of end devices. The Switch is configured to enable communication by the first set of end devices associated with the first fabric with the second set of end devices associated with the second set of end devices using the unique Domain_IDs of each of the first set and the second set of end devices. In one embodiment of the invention, the first and second fabrics are first and second Virtual Storage Array Networks (VSANs) respectively. In an alternative embodiment, the first fabric and the second fabric are separate physical fabrics.

Abstract: An Fibre Channel Switch which enables end devices in different Fabrics to communicate with one another while retaining their unique Fibre Channel Domain_IDs. The Switch is coupled to a first fabric having a first set of end devices and a second fabric having a second set of end devices. The Switch is configured to enable communication by the first set of end devices associated with the first fabric with the second set of end devices associated with the second set of end devices using the unique Domain_IDs of each of the first set and the second set of end devices. In one embodiment of the invention, the first and second fabrics are first and second Virtual Storage Array Networks (VSANs) respectively. In an alternative embodiment, the first fabric and the second fabric are separate physical fabrics.

Abstract: The Spanning Tree Protocol converges to a new configuration after the loss of a link. A new frame, known as a root link query request BPDU is transmitted to the root bridge in the spanning tree when a bridge detects an indirect link failure through the reception of an inferior BPDU on a blocked port. Each bridge forwards this root link query until the root link query reaches the last reachable upstream bridge or a bridge which has a different Tx_Root_Id than the one identified in the RLQ-REQ-BPDU. If the last reachable bridge is the root bridge identified in the RLQ-REQ-BPDU, then a second new frame known as an RLQ-ACK-BPDU is sent, and the bridge port receiving this acknowledgment BPDU is changed from a blocked port to a designated port. If the RLQ-REQ-BPDU reaches a bridge with a different Tx_Root_Id than the one in RLQ-REQ-BPDU, a third new frame known as RLQ-NAK-BPDU is sent.

Abstract: The Spanning Tree Protocol converges to a new configuration after the loss of a link. A new frame, known as a root link query request BPDU is transmitted to the root bridge in the spanning tree when a bridge detects an indirect link failure through the reception of an inferior BPDU on a blocked port. Each bridge forwards this root link query until the root link query reaches the last reachable upstream bridge or a bridge which has a different Tx_Root_Id than the one identified in the RLQ-REQ-BPDU. If the last reachable bridge is the root bridge identified in the RLQ-REQ-BPDU, then a second new frame known as an RLQ-ACK-BPDU is sent, and the bridge port receiving this acknowledgment BPDU is changed from a blocked port to a designated port. If the RLQ-REQ-BPDU reaches a bridge with a different Tx_Root_Id than the one in RLQ-REQ-BPDU, a third new frame known as RLQ-NAK-BPDU is sent.