Disk Versus Tape
Eversync disk-based backup appliances incorporate backup, disaster recovery, and archiving all in one easy-to-use, affordable package, and are a great alternative to tape backup. When comparing the cost of disk versus tape, the Eversync disk-based solution offers the lowest total cost of ownership compared to other disk-based backup solutions, as well as traditional tape backup solutions.
Tape Backup vs. Disk Backup - Pros & Cons
Customers evaluating alternative backup solutions to tape, or looking to replace their existing tape backup solution, will be faced with three basic options:
- a new tape backup solution
- a mix of disk and tape (disk-to-disk-to-tape) that uses disk as a staging space before data migrates to tape
- a fully SATA disk-based alternative (disk-to-disk-to-disk)
A quick summary of the differences between tape based backup solutions and disk based backup solutions is shown in the following table comparing tape vs disk backup, and shows why disk-to-disk-to-disk is the best alternative to tape backup:
|Scaling Performance||Poor||Better when accessing recent data, but poor for long term data||Best - disk is random access, and RAID allows for higher throughput|
|Reliability||Poor – tape stretches and suffers magnetic damage, backup tapes often fail||Poor – same issues with tape, backup tapes often fail||Good – disk drives and RAID make disk backups much more reliable than tape|
|Security||Poor tape reliability, lost or stolen tapes||Better||Best|
|Usability||Poor – managing tapes is one of the biggest issues IT managers face||Poor – doesn’t eliminate the issues with tape, and introduces multiple components||Easier to manage and maintain|
|RPO||Okay, but requires more full backups and more storage||Better for data still on disk, but requires more full backups and more storage||Great with more incremental backups|
|RTO||Poor||Better for recent data||Great for all data|
|Removability for Offsite Vaulting||Good||Good||Good, archive to disk (archive to removable drives)|
|Cost Savings Due to Capacity Reduction||None – limited deduplication and requires more full backups||Higher savings due to deduplication and less frequent need for full backups||Higher savings due to deduplication and less frequent need for full backups|
|Cost of Disk Versus Tape||High||High – complexity and licensing of multiple components, often from different vendors||Lower when using an integrated appliance|
|Long Term Archiving||Removable, but still a poor solution for long term data retention if you ever need to read the data||Poor solution for long term data retention||Capable of long term data retention and a much better alternative than tape backups kept on site or offsite; appliances include archive drives that can be used to archive to disk|
Moving to Disk-Based Backups
The high adoption of disk-based data protection solutions is a result of increasing data capacities and the unique ability of disk-based data protection solutions to meet backup windows that cannot be met with tape. The needs of businesses small and large have outpaced the capabilities of tape backup technologies in recent years.
See why the Eversync solution offers the lowest total cost of ownership compared to other disk-based backup solutions, as well as traditional tape backup solutions. See the white paper, “Achieving Increased Backup Availability and Reduced Backup Windwows with Disk-to-Disk-to-Disk“.
Major Advantages of Disk Technology Over Tape Technology
The reasons why people no longer use tape backup in favor of disk-to-disk-to-disk include:
The random access nature of disk drives enables the instant merging of incremental backups. Contrast this with tape, where multiple incremental backups are often spread across multiple tapes and likely to be far from the start of the tape. The RAID configuration of the disks in a backup appliance allows for redundancy and increased throughput by backing up and restoring multiple clients simultaneously. So when you need to restore a file, or even a single email, you can find it and restore it in a matter of minutes without sorting through any number of tapes.
Shorter Backup Windows
Disk-based backups reduce the backup windows in two ways. First, random access and higher reliability of the disk media means you can leverage more incremental backups per full backup. Full backups can be scheduled much less frequently, or selected to coincide with an expected lull in operations (for example, over the weekend). Since incremental backups typically need to save a small fraction of the total data, most backup windows become much shorter. Second, multiple clients can be backed up simultaneously with disk-based backup which results in higher throughput.
Economies of Incremental Backup
Leveraging more incremental backups not only helps with performance, but also with cost. Due to the additional time penalties of incremental tape restores and because tape restores frequently fail, almost all IT shops keep many copies of full (Level 0) backups in their tape libraries. Most tape backup schedules use no incremental backups or only a small number for each full backup set. That means there are often many redundant copies of the same file on tape. This significantly increases the $/TB of the tape media by wasting capacity on unnecessary duplicated file storage, and is the reason the cost of disk versus tape is higher.
Accelerated Backup and Archiving
Another benefit of disk-based backups is performance. Disk-based solutions leverage RAID performance and reliability to quickly back up and restore data.
When comparing tape versus hard disk drive (HDD) reliability, disk wins. Research has found that as many as 70% of tape recovery attempts fail. Disk-based solutions benefit from very reliable commodity disks, made even more reliable by using RAID to protect against disk failures. There are no tapes to misplace, or robotics to jam and recalibrate. Disk drives are self-contained and less sensitive to environmental conditions, so they can be reliably used for a longer period of time in more diverse environments. For most SATA drives, the manufacturer’s warranty is 5 years.
Disk-based solutions are easier to manage overall. The interfaces and concepts of file system, disk, and network attached storage (NAS) are familiar even to entry-level IT staff, meaning less training and fewer mistakes from the start.