Abstract: Embodiments of the invention support improvements in network performance in networks such as storage area networks. This is particularly important in networks such as those implementing virtualization. These improvements, therefore, support improved mechanisms for performing processing in network devices such as switches, routers, or hosts. These improvements include various different mechanisms which may be used separately or in combination with one another. These mechanisms include methods and apparatus for processing traffic in an arbitrated loop, performing striping to support fairness and/or loop tenancy, performing configuration of network devices such as switches to enable virtualization to be performed closest to the storage device (e.g., disk), ascertaining a CPU efficiency that quantifies the impact of virtualization on a processor, and configuring or accessing a striped volume to account for metadata stored in each storage partition.

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 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: Methods and apparatus for performing MUD logging for a volume in a system implementing network-based virtualization are disclosed. This is accomplished by enabling two or more MUD loggers to separately maintain a MUD log for the volume. Through enabling the MUD loggers to communicate, the MUD loggers may update their respective MUD logs. Each MUD log includes information for one or more epochs, where the information for each of the epochs indicates a set of one or more regions that have been modified during the corresponding epoch.

Abstract: Sets of ranges typically are maintained using an associative memory and may be used to identify a matching range based on a query point or query range and to maintain sorted elements for use, such as in providing priority queue operations. In one implementation, ranges are added to a set of ranges by determining a longest common prefix of a starting point and an ending point of the range, extending this longest common prefix by appending a bit to create a particular extended longest common prefix, and then storing it in the set of extended longest common prefixes. The set of extended longest common prefixes is then processed based on the query point or range to identify the matching range. Additionally, one implementation uses bands for identifying ranges, where the band is formed from the starting and ending points to the longest common matching prefix of the these points.

Abstract: Embodiments of the invention improve the detection of malicious software applications, such as a rootkit, on hosts configured to access storage volumes over a storage area network (SAN). A rootkit detection program running on a switch may be configured to detect rootkits present on the storage volumes of the SAN. Because the switch may mount and access storage volumes independently from the (possibly comprised) hosts, the rootkit is not able to conceal itself from the rootkit detection program running on the switch.

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: In one embodiment, a network device receives a port login directed to a target from a first host. The network device determines whether at least one other host is currently logged in to the target. The network device may then send a port login to the target corresponding to whether at least one other host is currently logged in to the target.

Abstract: A longest matching prefix is identified based on a search of ranges corresponding to the prefixes. These prefixes may correspond to any values, such as, but not limited to Internet Protocol (IP) or other network addresses, character strings, etc. A first-level tiny tree is traversed to identify a next-level tiny tree. A root node of the next-level tiny tree is retrieved. The root node typically includes a back value to identify a matching prefix should no matching prefix be identified within said particular tree. The particular next-level tiny tree is traversed to either identify a matching prefix or a no match condition, with the traversing said particular next-level tiny tree typically including comparing the lookup value with one or more of the plurality of keys. The prefix identified based on the back value is identified as the longest matching prefix if said traversing resulted in said no match condition else the matching prefix.

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 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: Methods and apparatus are disclosed for distributing entries among lookup units and selectively enabling less than all of the lookup units when performing a lookup operation. Each of the lookup units is assigned a subset of the possible values of the entries and is programmed with the corresponding entries. In performing a lookup operation on a lookup word, only the lookup units possibly containing a matching entry are enabled which saves power and dissipates less heat. A lookup operation is then performed in the enabled lookup units to generate the lookup result. A lookup unit may correspond to an associative memory device, an associative memory bank, sets of entries within one or more associative memory devices or banks, a lookup control and a memory device, and/or any other lookup mechanism. In one implementation, the partitioning of elements is based on a Patricia tree representation of the possible entries.

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: An apparatus and method of using same for associating a tag with each packet in an ATM switch to eliminate the need for an OVC table, thus saving both egress processing time and memory resources. The tag includes both a type of switching identifier and a per-logical-interface or per-external-VC information field. A packet received by the egress packet processing engine has associated with it (by the control plane) a frame control word containing a new cell header (NCH) corresponding to the OVC on which the packet was received from the fabric. This NCH contains the tag used to expedite egress processing. In one embodiment of the present invention, the tag value is provided in two fields, a tag type and a tag parameter. The tag type represents a code for different data path applications. The tag parameter takes on multiple values based on the tag type.

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: Methods and apparatus for processing a reserve request requesting a reservation of at least a portion of a volume in a system implementing network-based virtualization of storage are disclosed. More particularly, multiple ports and/or network devices together implement the virtualization of storage. When a network device or port receives a reserve request from a host requesting that at least a portion of a volume be reserved, a notification is sent indicating the at least a portion of the volume being reserved. The notification may be sent to one or more network devices or ports. A lock corresponding to the reserve request may then be obtained such that a lock of the at least a portion of the volume is acquired. When another network device or port receives a reserve intention notification, the network device or port stores information indicating that a lock of the at least a portion of the volume has been obtained.

Abstract: Methods and apparatus for performing MUD logging for a volume in a system implementing network-based virtualization are disclosed. This is accomplished by enabling two or more MUD loggers to separately maintain a MUD log for the volume. Through enabling the MUD loggers to communicate, the MUD loggers may update their respective MUD logs. Each MUD log includes information for one or more epochs, where the information for each of the epochs indicates a set of one or more regions that have been modified during the corresponding epoch.

Abstract: Methods and apparatus are disclosed for longest common prefix based caching. An information space is partitioned into multiple subsets such that a particular subset including a particular prefix also includes all longer prefixes beginning with the particular prefix in the information space. A primary control unit typically maintains the information space and all of the subsets, and selectively distributes some or all of the subsets to basic control units, and each of basic control units does not necessarily receive the same group of subsets. In addition, the group of subsets maintained by a particular basic control unit may change during operation, typically to increase the likelihood that a particular basic control unit will contain the needed subset.

Abstract: Zone information is automatically and dynamically configured and managed in a fibre channel storage area network upon detection of network events. Some examples of events that trigger automatic dynamic zone updates include virtual port creation, intrusion/anomaly detection, arbitration decision completion, misconfiguration detection, and device malfunction. The newly created/updated zones are propagated through the fibre channel fabric and provide access control.