A big breakthrough: Cloud snapshots

The Microsoft HCS solution incorporates elements from backup, dedupe, and snapshot technologies to create a highly automated data protection system based on cloud snapshots. A cloud snapshot is like a storage snapshot but where the snapshot data is stored in Windows Azure Storage instead of in a storage array. Cloud snapshots provide system administrators with a tool they already know and love—snapshots—and extend them across the hybrid cloud boundary.

Fingerprints in the cloud
The data objects that are stored as snapshots in the cloud are called fingerprints. Fingerprints are logical data containers that are created early in the data lifecycle when data is moved out of the input queue in the CiS system. While CiS systems store and serve block data to servers, they manage the data internally as fingerprints.

Just as backup processes work by copying newly written data to tapes or disk, cloud snapshots
work by copying newly made fingerprints to Windows Azure Storage. One of the biggest differences between backup and cloud snapshots is that backup transforms the data by copying it into a different data format, whereas cloud snapshots copy fingerprints as-is without changing the data format. This means that fingerprints in Windows Azure Storage can be directly accessed by the CiS system and used for any storage management purpose.

Cloud snapshots work like incremental-only backups insofar that fingerprints only need to be uploaded once to Windows Azure Storage. Replication services in Windows Azure Storage makes multiple copies of the data as protection against failures. With most backup systems, there are many different backup data sets that need to be tracked and managed, but with cloud snapshots, there is only a single repository of fingerprints. In addition, there is no need to create synthetic full tapes because all the fingerprints needed to be recovered are located in the same Windows Azure Storage bucket.

Scheduling cloud snapshots
IT teams can flexibly configure their CiS systems to perform automated cloud snapshots to meet a broad range of requirements. Unlike tape backup systems that necessarily tie data expiration to tape rotation schedules, cloud snapshots can be assigned any expiration period. For instance, if the IT team decides they want to keep all cloud snapshot data for a minimum of three months, they can do it without having to worry about which tapes to use. Also, if the IT team wants to upload data more frequently, they can run cloud snapshots several times a day.

Efficiency improvements with cloud snapshots
Cloud snapshots eliminate tape problems and operator errors because there are no tapes to manage, lose, or go bad. No tapes need to be loaded for the next backup operation, no tapes are transferred off site, there are no tape names and labels to worry about, and no courier services need to be engaged. The arcane best practices that were developed for tape backup no longer apply to cloud snapshots. This is an enormous time saver for the IT team and removes them from the drudgery of managing tapes, tape equipment, and backup processes. Data protection with cloud snapshots also eliminates the need to make full or synthetic full tapes. The incremental-only approach of cloud snapshots means that a minimal amount of data is copied and transferred. In addition, the fact that data is deduped on-premises before it is snapshotted means the amount of data that is uploaded is minimized.

Comparing cloud snapshots
The biggest difference between cloud snapshots with the Microsoft HCS solution and other backup products is the integration with Windows Azure Storage. Cloud snapshots improve data protection in three important ways:

1. Off-site automation. Cloud snapshots automatically copy data off site to Windows Azure Storage.

2. Access to off-site data. Cloud snapshot data stored off site is quickly accessed on premises.

3. Unlimited data storage and retention. The amount of backup data that can be retained on Windows Azure Storage is virtually unlimited.

Remote replication can be used to enhance disk-based backup and snapshot solutions by automating off-site data protection. The biggest difference between cloud snapshots and replication-empowered solutions is that replication has the added expense of remote systems and facilities overhead, including the cost of managing disk capacities and replication links.

Remote office data protection
Cloud snapshots are also effective for automating data protection in remote and branch offices (ROBOs). These locations often do not have skilled IT team members on site to manage backup, and as a result, it is common for companies with many ROBOs to have significant gaps in their data protection.

Installing the Microsoft HCS solution in ROBO locations allows the IT team to completely automate data protection in Windows Azure Storage. This highlights another important architectural advantage—the many to one (N:1) relationship of on-premises locations to cloud storage. This design makes it possible for a Microsoft HCS solution at a corporate data center to access data from any of the ROBO locations. In addition, alerts from CiS systems running in the ROBOs can be sent to the IT team so they can remotely troubleshoot any problems that arise.

The role of local snapshots
CiS systems also provide local snapshots that are stored on the CiS system. Although local and cloud snapshots are managed independently, the first step in performing a cloud snapshot is running a local snapshot. In other words, all the data that is snapped to the cloud is also snapped locally first. The IT team can schedule local snapshots to run on a regular schedule—many times a day and on demand.

Looking beyond disaster protection
Snapshot technology is based on a system of pointers that provide access to all the versions of data stored by the system. The Microsoft HCS solution has pointers that provides access to all the fingerprints stored on the CiS system and in Windows Azure Storage.

The fingerprints and pointers in a Microsoft HCS solution are useful for much more than disaster protection and accessing point-in-time copies of data. Together they form a hybrid data management system that spans the hybrid cloud boundary. A set of pointers accompanies every cloud snapshot that is uploaded to Windows Azure Storage, referencing the fingerprints that are stored there. The system of pointers and fingerprints in the cloud is a portable data volume that uses Windows Azure Storage for both protection and portability.

This hybrid data management system enables additional data and storage management functions beyond backup and disaster recovery. For example, data tiering and archiving both take advantage of it to manage data growth and drive storage efficiency. 

Source of Information : Rethinking Enterprise Storage

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