1. OST Virtual Synthetics 1

2. Synthetics Overvier Definitions – Catalog – Image – Extent Process Overview (today) – Extent map derivation – Read agenda – Data movement – Validate completed image Virtual Synthetics – Implementation OST Virtual Synthetics 2

3. Definitions (For Synth Puproses) Catalog – Database of backup metadata – Backups known to Netbackup, location on media – Files within a backup, including location and size Image – Container for backup data – Whole backup or part; one or more fragments Extent – Representation of data chunk within a backup – Block offset into backup and number of blocks in length – Blocks are 512 bytes OST Virtual Synthetics 3

4. Extent Map Derivation This is a catalog operation – Looks back through recent history of backups for a given policy. – Develops a combination of full + incrementals necessary to synthesize a new backup. – Uses file metadata of incremental backups to determine files added, replaced, or deleted after the full backup. – Extent mapping is derived by choosing most recent instance of a file. Results in: – A set of extents mapped to backup id. – Extent set for most recent backup is first, oldest is last – Extent list is in block ascending order for each backup. – Overall extent list is ordered by how the extents should appear in the resulting backup OST Virtual Synthetics 4

5. Read Agenda Synthetics today allows read from any backup on any media server and write to any media server. – Heterogeneous capability provides value with costs – Tape read/write strategy results in sequential extent reading and writing. Synth reprocesses the extent mapping – Chooses source copy and maps source media – Extents may be divided to reflect fragmentation. Read agenda is based on extent sets for each media – One reader for each backup on each media OST Virtual Synthetics 5

6. Data movement and Validation Writer is launched, targeting new media with a new backup id Readers are launched synchronously: – Each reader will read large contiguous extents of the source image. – The reader filters the data read according to the extent mapping for the backup. – Passes data to the writer via a socket. When all readers and the writer is done, new image is marked complete. – This signals to the rest of Netbackup that the image is ready for restores, duplication, and future synthetics. Presentation Identifier Goes Here 6

7. Virtual Synthetics Goals – Produce synthetic backups with little or no copying involving a NBU data mover – A fully virtual image would involve linking data in existing images into a new image. Uses stsp_include_in_image(). – Make synthetics a metadata operation rather than a data movement. – Cheapen “synthetics forever” Realizations – On-disk organization is driven by capability of the storage server. Allows storage servers to bring their value to the Netbackup equation. – Inferred relationship given by stsp_include_in_image() could be used to perform better SIS. – Virtual images can be used to re-organize existing images (alternative views) OST Virtual Synthetics 7

8. Virtual Synthetics Realizations (con’t) – Synth to 2nd storage server could be a local synth plus optimized duplication – Extents in new image can be ordered based on need rather than data movement. Implementation – Source images and target LSU must be on the same storage server. – Storage server advertises “include in image” support. – Netbackup detects this capability and uses it to dynamically choose whether to use a virtual synthetic operations or default to the traditional non-virtual synthetic backup. – Extent mapping and read agenda are constructed similarly to the non- traditional synthetic backup method. OST Virtual Synthetics 8

9. Virtual Synthetics Implementation (con’t) – Target image is constructed sequentially. – Source images are opened as needed. – The “include in image” operations are performed by one Netbackup media server. – Resulting image should be identical and indistinguishable from an image constructed using the non-virtual method. OST Virtual Synthetics 9

10. Thank you! Copyright © 2011 Symantec Corporation. All rights reserved. Symantec and the Symantec Logo are trademarks or registered trademarks of Symantec Corporation or its affiliates in the U.S. and other countries. Other names may be trademarks of their respective owners. This document is provided for informational purposes only and is not intended as advertising. All warranties relating to the information in this document, either express or implied, are disclaimed to the maximum extent allowed by law. The information in this document is subject to change without notice. OST Virtual Synthetics 10