Emc Corporation

Hongmei Wang

Philippe Armangau

Milena Bergant

John Michael Hayden

Frederic Corniquet

Richard Hooker

Raymond Angelone

Ashok Ramakrishnan

Pascal Donette

Aju John

Ajay S Potnis

Joseph A Leslie

A method is used in managing initialization of file systems. Activity of file systems is monitored. The file systems include a first and second set of file systems. Based on activity of the file systems, the first set of file systems is associated with a first section of a boot configuration file and the second set of file systems is associated with a second section of the boot configuration file. The first and second sets of file systems are initialized for providing access to the first and second sets of file systems. Access to the first set of file systems is provided before initializing the second set of file systems.

Managing initialization of file systems

For disaster recovery of a file server at an active site, the files that define the user environment of the file server are replicated to a virtual server at a disaster recovery site. To switch over user access from the active site to the disaster recovery site, the disaster recovery system determines whether there are sufficient network interfaces and file system mounts at the disaster recovery site. If so, the required resources are reserved, and user access is switched over. If not, an operator is given a list of missing resources or discrepancies, and a choice of termination or forced failover. Interruptions during the failover can be avoided by maintaining a copy of user mappings and a copy of session information at the disaster recovery site, and keeping alive client-server connections and re-directing client requests from the active site to the disaster recovery site.

Internet protocol based disaster recovery of a server

A file server maintains a production file system supported by a clone volume, and multiple snapshot file systems supported by respective save volumes in a snapshot queue. Before a data block is modified for the first time after creation of the youngest snapshot, the data block is copied from the clone volume to the save volume of the youngest snapshot. A bit map indicates the blocks that have already been copied, and a block map shows the save block address for each corresponding clone block address. When a new snapshot is created, the bit and block maps are converted to a hash index that is kept linked to the save volume of what had been the youngest snapshot. When other than the oldest snapshot file system is deleted, the respective save volume is retained as a hidden object until it becomes the oldest save volume.

Organization of multiple snapshot copies in a data storage system

Growing community of inventors

Shrewsbury, MA, United States of America

Hongmei Wang