Abstract: A replicated decentralized storage system comprises a plurality of servers that locally store disk images for locally running virtual machines as well as disk images, for failover purposes, for remotely running virtual machines. To ensure that disk images stored for failover purposes are properly replicated upon an update of the disk image on the server running the virtual machine, a hash of a unique value known only to the server running the virtual machine is used to verify the origin of update operations that have been transmitted by the server to the other servers storing replications of the disk image for failover purposes. If verified, the update operations are added to such failover disk images.

Abstract: A two dimensional bit array is maintained to keep track of the location of data records in a log file that is organized as a plurality of log segments, each comprising a plurality of data records. The data records are indexed in the log file according to randomized unique ids. Each column of the two dimensional bit array represents a Bloom filter corresponding to a log segment of the log file such that, given a particular randomized unique id, log segments that may contain the data record corresponding to the particular randomized unique id can be efficiently identified by utilizing Bloom filter techniques to analyze the columns of the two dimensional bit array.

Abstract: Dynamic program analysis is decoupled from execution in virtual computer environments so that program analysis can be performed on a running computer program without affecting or perturbing the workload of the system on which the program is executing. Decoupled dynamic program analysis is enabled by separating execution and analysis into two tasks: (1) recording, where system execution is recorded with minimal interference, and (2) analysis, where the execution is replayed and analyzed. Recording and analysis are carried out on heterogeneous systems so that they can be separately optimized.

Abstract: An analytics engine receives real-time statistics from a set of virtual machines supporting a line of business (LOB) application. The statistics relate to computing resource utilization and are used by the analytics engine to generate a prediction of demand for the LOB application in order to dynamically control the provisioning of virtual machines to support the LOB application.

Abstract: A server supporting the implementation of virtual machines includes a local memory used for caching, such as a solid state device drive. During I/O intensive processes, such as a boot storm, a “content aware” cache filter component of the hypervisor of the server first accesses a cache structure in a content cache device to determine whether data blocks have been stored in the cache structure prior to requesting the data blocks from a networked disk array via a standard I/O stack of the hypervisor. The content aware cache filter component is implemented in an I/O virtualization layer of the standard I/O stack that sits above a file system layer of the standard I/O stack, such that any file system protocol may be implemented in the file system layer.

Abstract: A replicated decentralized storage system comprises a plurality of servers that locally store disk images for locally running virtual machines as well as disk images, for failover purposes, for remotely running virtual machines. To ensure that disk images stored for failover purposes are properly replicated upon an update of the disk image on the server running the virtual machine, a hash of a unique value known only to the server running the virtual machine is used to verify the origin of update operations that have been transmitted by the server to the other servers storing replications of the disk image for failover purposes. If verified, the update operations are added to such failover disk images. To enable the replicated decentralized system to recover from a failure of the primary server, the master secret is subdivided into parts and distributed to other servers in the cluster.

Abstract: A checkpointing fault tolerance network architecture enables a backup computer system to be remotely located from a primary computer system. An intermediary computer system is situated between the primary computer system and the backup computer system to manage the transmission of checkpoint information to the backup VM in an efficient manner. The intermediary computer system is networked to the primary VM through a high bandwidth connection but is networked to the backup VM through a lower bandwidth connection. The intermediary computer system identifies updated data corresponding to memory pages that have been least recently modified by the primary VM and transmits such updated data to the backup VM through the low bandwidth connection. In such manner, the intermediary computer system economizes the bandwidth capacity of the low bandwidth connection, holding back updated data corresponding to more recently modified memory pages, since such memory pages may be more likely to be updated again in the future.