Symantec Corporation

Emc IP Holding Company LLC

Emc Corporation

Veritas Technologies LLC

Kedar Shrikrishna Patwardhan

Anindya Banerjee

Sanjay Kumar Jain

Sushil Sarjerao Patil

Suraj M Multani

Niranjan Sanjiv Pendharkar

Anand Ghatnekar

Shailesh Marathe

Dilip Madhusudan Ranade

Brad Boyer

Ryan Lefevre

Freddy James

Manjunath Tadahal

Mitul Kothari

Neha Naik

Rahul Ravindra Borade

Navneet Upadhyay

Scott H Ogata

Samir Desai

Kirubakaran Kaliannan

Maneesh Pusalkar

Balemurughan Kumaresan

Rajesh K Nair

Anirban Mukherjee

Venkatraman Venkatasubramanyam

Harold Bailey Prince, Jr

Mangesh Sudhir Nijasure

Veeral Shah

Sudheer Keshav Chepa

Amit Jambure

Rachit Chadha

Ramprasad Chinthekindi

Systems and methods for performing backups including incremental backups are provided. A change log is provided. The change log includes a map file that includes a bit for each inode in a file system. The bits are set on certain file events. The map file allows the files to be included in the next backup to be identified without having to trawl the entire file system. The change log also includes a data file that lists actual changes to the various files in corresponding records that are indexed by the inode number. The change log can enable faster incremental backups in part by eliminating unnecessary disk access requests.

Summary file change log for faster forever incremental backup

A summary change log indexed by inode number is disclosed. An indication is received that a file system object associated with a corresponding file system index node (inode) has been modified. A summary change record is stored for the corresponding inode, including by: locating or creating an entry for the inode in an inode translation file; storing data associated with the modification in a summary change record located within a summary change file at an offset indicated in the entry; and using the summary change record to perform a backup.

Summary change log indexed by inode numbers

One embodiment provides a computer implemented method of data identification within a deduplication storage system, the method comprising processing multiple units of a segment of data within the deduplication storage system using a fingerprint generation algorithm; storing the internal state generated while processing the multiple units of the segment of data; generating a first fingerprint for the segment of data based on the internal state; reloading the internal state after generating the first fingerprint for the segment of data; and generating a second fingerprint for the segment of data based on a transformed unit of the segment of data.

Enhanced fingerprint computation for de-duplicated data

A method includes identifying a state of an application and taking a snapshot of application data. The method continues to generate a virtual filter input/output snapshot from I/O filter records for the snapshot. The filer records are generated by a filter driver that intercepts I/Os between the application and disks that store application data. The method further includes releasing the snapshot, resuming the application and performing a backup using the virtual filter I/O snapshot. Finally, the method triggers the filter driver to replace multiple filter driver records corresponding to the virtual filter I/O snapshot with data indicating the application data was backed up using the virtual filter I/O snapshot.

Agent aware selective backup of a virtual machine using virtual I/O filter snapshots

Techniques to back up data are disclosed. In various embodiments, a copy of a free block map as of a first time associated with a first backup is stored in persistent data storage. Writes made subsequent to the first backup to blocks not listed as free in the copy of the free block map as of the first time are tracked in a persistently-stored change block tracking log. A free block map as of a second time and the previously-stored copy of the free block map as of the first time are used to determine which blocks listed as free in the free block map as of the first time have been written to since the first time. At least a subset of blocks determined to have been written to since the first time are including in an incremental backup.

Optimization to permit block based incremental backup across system reboot or crash

Incrementally backing up file system hard links based on change logs is described. A system identifies a unique identifier and a file name associated with a file event in a file system. The system determines whether a change log for the file system lacks an association between the unique identifier and the file name. The system adds the file name to one of a new file name list and a deleted file name list associated with the change log in response to a determination that the change log for the file system lacks the association between the unique identifier and the file name. The system incrementally backs up the file event based on at least one of the new file name list and the deleted file name list.

Incrementally backing up file system hard links based on change logs

A cloud storage system stores data objects from different customers. Each customer has their own encryption key to encrypt the data objects for storage and the key is not shared. To deduplicate the data objects, a set of base fingerprints associated with a set of base data objects is stored. A first fingerprint associated with a data object from a customer is compared with a base fingerprint. The first and base fingerprints are generated by applying an identical fingerprinting algorithm to unencrypted versions of the data objects. If the fingerprints match, the first fingerprint is associated with a base data object corresponding to the matching base fingerprint, and the data object from the customer is not stored. If the fingerprints do not match, the data object from the customer is stored.

System and method for a cloud storage provider to safely deduplicate encrypted backup objects

A computer-implemented method for enhancing data transfer is disclosed. The method starts with capturing a snapshot of a storage volume and creating a snapshot volume in response to receiving a request for backing up data from the storage volume of a storage system. Upon receiving a write request for writing a new block to a block location of the storage volume while the storage system is performing a backup operation from the snapshot volume to a target storage system, the storage system performs data preservation for the block location only if the block location to be written is not free, otherwise the new block is written to the block location of the storage volume based on the write request without preservation.

Method and system for enhancing data transfer at a storage system

Recording file events in change logs while incrementally backing up file systems is described. A system begins incrementally backing up a file system by reading a current change log. The system identifies a file event associated with the file system while incrementally backing up the file system. The system identifies a unique identifier associated with the file event. The system determines whether the unique identifier associated with the file event is greater than a unique identifier offset associated with reading the current change log. The system records the file event in the current change log in response to a determination that the unique identifier associated with the file event is greater than the unique identifier associated with reading the current change log.

Recording file events in change logs while incrementally backing up file systems

Various computer-implemented methods for selective defragmentation are disclosed. In one example, an exemplary method for performing such a task may include: 1) identifying a file system, 2) tracking changes to files in the file system, 3) creating a list of changed files, and then 4) selectively defragmenting files in the list of changed files. Various other methods, systems, and computer-readable media are also disclosed.

Systems and methods for selective defragmentation

Various systems and methods use advisory metadata to track the status of file system objects. For example, one method can involve accessing a first item of advisory metadata, which is associated with a namespace-visible parent directory and identifies a first transaction and a first time, and accessing a second item of advisory metadata, which is also associated with the namespace-visible parent directory and identifies a second transaction and a second time. The namespace visible parent directory includes multiple namespace-hidden directories. The method can then select a time value of the advisory metadata for the namespace-visible parent directory, based upon the first item and the second item. The method can be performed by a computing device implementing a file system.

Timestamp handling for partitioned directories

A method for file system checking in a storage device. The method includes executing a computer system having a plurality microprocessor cores, initiating a file system check operation by using a file system check agent that execute on the computer system and accesses a storage device, and validating a plurality of meta-data structures of the file system. The method further includes dividing and allocating the metadata structures among a plurality of worker threads. For each worker thread, data corresponding to the metadata structures is processed using a read ahead operation. file system check is processed to completion, wherein the read ahead operation feeds data corresponding to the metadata structures to each of the plurality of worker threads in parallel.

Method and system for a fast full style system check using multithreaded read ahead

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Maharashtra, India

Kedar Shrikrishna Patwardhan