This post is the first in a series to share with you 5 ways disk backup can help your business:
- Faster Backup Times
- Reduce or Eliminate Failed Backups
- Better, Faster Offsite Disaster Recovery
- Time and Cost Savings
- Improved Recovery Time (RTO/RPO)
In this post, we will discuss the first topic--how disk backup enables IT organizations to dramatically reduce their backup times.
1. Faster Backup Times
While tape backup systems have been in use for many years, the slow speed of tape backup devices is a major reason many organizations have looked for a better, faster way to back up their data. One of the key reasons many organizations move to a disk backup solution is in fact the inherent advantage of disk for faster backups. Moving from tape to disk will get you faster backups, but it is also important to choose the correct disk backup approach, and to ensure that you will continue to get faster backup times as your data grows.
Disk vs. Tape
While some might argue that some tape-based approaches might allow for a particular backup job to move at rate on par with disk, the key advantage of disk-based backup over tape is the ability to run a large number of backup jobs in parallel. The number of backup jobs you can run via tape-based backup is only as high as the number of tape drives in your tape library – at most four simultaneous backup jobs can target a four-drive tape library, for example. This limit is much higher with disk – a 50TB ExaGrid system can support up to 100 simultaneous backup jobs – and the ability to run this many backup jobs in parallel will allow for much higher backup speeds with disk over tape. Click here for additional discussion of disk backup vs. tape backup performance.
Post-process vs. Inline Deduplication
Once you have decided to move to a disk-based backup system, to achieve fastest backup times, it is important to consider the various deduplication approaches available when deciding which system to choose. This decision typically comes down to a choice between inline deduplication and post-process deduplication.
With inline deduplication, backup data is sent to the disk backup system and is processed and deduplicated as the data comes into the system. Since all of the data coming into the system is being deduplicated on the fly, this can slow the backup down significantly, potentially creating a bottleneck at the point of entry into the backup system.
Post-process deduplication allows backup data to be written to disk without any processing interfering with the backup flow. A post-process system compresses and deduplicates the data after the backup job has landed on the disk – not as the data is coming into the system. This is the approach that the ExaGrid system uses. Since nothing is done to the data as it comes into the ExaGrid system, the data can be written at the highest possible rate, giving you the smallest possible backup window.
Planning for Growth
While it is desirable to strive for as short a backup window as possible today, it is also important to keep that backup window short over time, as your data grows. After all, what good is a short backup window if it’s just going to get longer as your backup jobs get bigger?
With some of the current appliance architectures, keeping the backup window short while allowing for data growth means replacing your backup appliance with bigger and more powerful models of that appliance. This occurs because many of these disk backup systems use what is called a controller-disk shelf model, where all of the processing power, memory, and bandwidth are on a single controller system, and expansion occurs by simply adding shelves of disk (with no incremental addition of controller components) to the system. This is not the best solution, as eventually your data needs eventually outstrip the original controller component, and you end up migrating to a system with a more powerful controller and start the process all over again. The result is greater expense and greater management costs as you migrate your data to ever-larger appliances as your data needs grow.
A better alternative is a grid-based system. With a grid-based system, each appliance in the system brings with it not only additional disk, but also additional memory, bandwidth, and processing power – all the elements needed to maintain high backup performance. With ExaGrid’s grid-based disk backup system, keeping your backup window short as your data grows is simply a matter of adding additional appliances to the grid. There is no need to replace less powerful appliances with more powerful ones – you simply add more appliances to the grid as suits your needs. You get the shortest possible backup times, with the ability to easily keep those times short as your data grows, over time.
Want to learn more about making the move from tape to disk backup with deduplication? Download '7 Steps for Overcoming Limitations of Tape Backup' here.