| Attribute/Capability |
Post-Process with Byte-Level Deduplication |
Inline with Block-Level Deduplication |
| Highest performance for shortest backup window |
Fastest
Writes to the disk at disk speed to ensure completion of the backups quickly. |
Slower
Performs compute-intensive process between the backup server and disk. |
| High performance maintained as data grows to keep short backup window |
Strong — can add full appliances
Backup jobs are broken into 50MB to 100MB segments and then compared to find the bytes that change. Due to the large size of the segments—thousands of them at 10TB—the tracking data can be copied across full servers each with their own processor, memory, bandwidth and disk. As a result, full appliances are added versus just disk. When you grow from 10TB to 20TB (twice the data) the processor, memory, bandwidth and disk all double which means you have twice the resources. This results in a backup window that stays the same length. |
Weak — can only add disk
Uses roughly 8KB blocks, which produces a hash tracking table of a billion entries at just 10TB. Due to the size of the hash table and prohibitive cost of memory to store the entire hash table multiple times, the hash table needs to be kept in a front-end server—and therefore, only disk shelves are added as data grows. If your backup grows from 10TB to 20TB, only disk is added while the processor, memory and bandwidth stay the same. With twice as much data but the same processor and memory, as the data grows, the backup window expands. |
| Fast full system restores |
Fastest Restores
Keeps full copy of most recent backups and historical versions as byte-level deltas behind the most recent backup. Latest full copy is always ready to restore in complete form for fastest full system restores. |
Slower Restores
Deduplicates data on the fly so all data on disk is deduplicated. When doing a full system restore— often time-sensitive—you have to wait for all of the data to be put back together (rehydrated). |
| Fast offsite tape copy |
Fastest Tape Copies
Keeps a full copy, so when your Friday night backup is complete, the full backup is sitting on the disk waiting to be copied to tape. The tape copy job simply copies the full backup from disk to tape without any data rehydration time, resulting in fastest tape copies. |
Slow Tape Copies
Deduplicates data on the fly so during the Friday night full backup, data is deduplicated on the way to disk. As soon as the Friday night full is complete and the offsite tape copy starts, the entire full backup needs to be put back together (rehydrated) which makes for slow tape copies. |
| Fast older backup version restores |
Rehydrate Older Versions
Takes similar time to restore older versions as inline/block-level deduplication. |
Rehydrate Older Versions
Takes similar time to restore older versions as post-process/byte-level deduplication. |
| Plug-and-play installation |
Plug-and-Play Appliance
Simple to initially install. |
Plug-and-Play Appliance
Simple to initially install. |
| Simplified GUI-based management and comprehensive reporting |
Simplified Management, Content-Aware Reporting
Management of multiple sites and devices via single web-based UI. Job-level reporting of deduplication ratio and replication status makes it easy to determine how to optimize backups. |
Complex Management, Generic Reports
Configuration of system via command-level interface (CLI) per device. Reporting of dedupe ratios and replication status just by device, not at job level. |
| Cost-effective up-front purchase |
Best Price for Highest Performance
Performs the processing after the backups are complete. Therefore, the systems can utilize mass market Intel processors that are shipped in high quantity and therefore are inexpensive. This greatly reduces the cost of the system. These systems can be up to as much as 30% less than an inline/block system. |
Higher Price
Due to the inline approach, this requires the most recent, high-performance CPU in order to keep up with backups. The premium processor and memory drives the cost of the system up. These systems are more expensive than post process/ byte. |
| Cost effectiveness as data grows |
Cost Effective to Scale
Uses full servers. As data grows you add another server into a GRID architecture. Each server comes with processor, memory, bandwidth and disk. When your data goes from 10TB to 40TB, you simply keep adding more appliances and the system keeps growing. There are no forklift upgrade points and no future costs to consider. Just add as you grow. |
Costly to Scale
Disk is added as data grows, but at some point the front-end server can no longer keep up because the amount of disk you can add behind fixed processor, memory and bandwidth is limited. At some point the front-end server must be replaced with a server that has faster processor and memory, which is called a “forklift” upgrade. Some product lines have as many as five forklift upgrade points. Since the cost of the front-end can be as much as the price of the initial system, when you buy in and then hit a forklift upgrade point, you may have to spend about as much for the upgrade as what you originally spent. |
| Strong technical customer support |
Depends on the Company
Ask each company about their support models. |
Depends on the Company
Ask each company about their support models. |
Datum > Products > ExaGrid Systems > ExaGrid vs Other Appliance
