Techniques such as replication and erasure coding protect data on object storage systems and other high-capacity primary storage systems when traditional backup is difficult.

Object storage systems are designed to cost effectively store a lot of data for a very long period of time. However, that makes traditional backup difficult, if not impossible. To ensure data is protected from both disk failure and corruption, vendors use replication or erasure coding (or a combination of the two).

Even if you are not considering object storage, understanding the differences between these data protection techniques is important since many primary storage arrays are beginning to use them. We explore the pros and cons of each approach so you can determine which method of data protection is best for your data center.

Scale-out basics

Most object storage systems, as well as converged systems, rely on scale-out storage architectures. These architectures are built around a cluster of servers that provide storage capacity and performance. Each time another node is added to the cluster, the performance and capacity of the overall cluster is increased.

These systems require redundancy across multiple storage nodes so that if one node fails, data can still be accessed. Typical RAID levels such as RAID 5 and RAID 6 are particularly ill-suited for this multi-node data distribution because of their slow rebuild times.

Replication pros and cons

Replication was the most prevalent form of data protection in early object storage systems and is becoming a common data protection technique in converged infrastructures, which are also node-based.

In this protection scheme, each unique object is copied a given number of times to a specified number of nodes, where the number of copies and how they're distributed (how many nodes receive a copy) is set manually or by policy. Many of these products also have the ability to control the location of the nodes that will receive the copies. They can be in different racks, different rows and, of course, different data centers.

The advantage of replication is that it is a relatively lightweight process, in that no complex calculations have to be made (compared with erasure coding). Also, it creates fully usable, standalone copies that are not dependent on any other data set for access. In converged or hyperconverged architectures, replication also allows for better virtual machine performance since all data can be served up locally.

The obvious downside to replication is that full, complete copies are made, and each redundant copy consumes that much more storage capacity. For smaller environments, this can be a minor detail. For environments with multiple petabytes of information, it can be a real problem. For example, a 5 PB environment could require 15 PB of total capacity, assuming a relatively common three-copy strategy.

Mounting a virtual machine image can save time, but there's a penalty to pay for the convenience. We list the questions to ask when deciding which data protection method to employ.

Backup software today is not the file backup software of yesteryear. It has evolved significantly to back up virtual machines (VMs); containers; cloud applications; edge devices such as laptops, tablets and smartphones; websites and more. But one of the data protection methods generating a lot of excitement is the ability of backup software products to mount a virtual or physical machine image directly on the backup or media server as a VM and put it into production. This capability is a game-changer when it comes to system-level recoveries because it enables server systems to be brought back in minutes -- a system no longer has to be recovered on new hardware and then put back into production.

So when does it make sense to mount a backup versus recover from a backup?

Challenges with mounting backups

Mounting backups and running them on media or backup servers decreases recovery time objectives (RTOs) by orders of magnitude, but the technology is subject to real limitations. For example, backups mounted on a media or backup server will often run in a degraded state, although exceptions exist when there is a separate physical host for those mounts. Media or backup servers are sized for backups, not application production and ongoing backups, so organizations should ask and answer the following questions while planning their data protection methods:

• How often do physical hosts fail?
• Will the budget allow for overprovisioning media or backup servers?
• If not, can applications, application owners or users tolerate running in a degraded mode if there is a physical host failure?
• How much degradation can users tolerate?

When answering these questions, many data protection professionals will envision a single VM running concurrently with the backups on that media or backup server. But that's an unrealistic scenario today. Should a physical host die, there will be far more than a single VM that will have to be brought up on media or backup servers. Additionally, most media or backup servers back up more than one hypervisor-equipped host plus other nonhypervisor-equipped hosts. Should there be a multiple host outage, each media or backup server will likely have to mount several dozen VMs concurrently.

The majority of workers in the UK agree that the loss or theft of their digital data is inevitable at some point.

This is according to a survey of 2,000 Brits conducted by Citrix, which found 71 per cent of respondents have accepted the fact they will fall victim to this problem sooner or later.

Younger individuals were found to be more alert to the risks, with a third of 16 to 25-year-olds saying they felt more vulnerable to attacks than in the past, compared with just 15 per cent of over-65s.

However, despite this, a large number of people are still relying on outdated solutions when it comes to backing up their most valuable data.

Nearly a third of respondents (30 per cent) said they still used USB sticks to back up key information, while just nine per cent have turned to a cloud-based service to do this.

Chris Mayers, chief security architect at Citrix, said: "Many [workers] are still reliant on dated practices such as using USB sticks to store and protect their information, when more advanced and robust measures are available."

Reference: http://www.krollontrack.co.uk/company/press-room/data-recovery-news/data-loss-inevitable,-brits-say531.aspx

It goes without saying that the amount of data we create is continually increasing. Methods of storing it are numerous and hard drive manufacturers are tempting us with greater capacity, speed, and – for a change – lower prices. So what storage medium should you choose?

What are the Choices?

1. Optical Storage
2. Hard Disk and Solid State Drives
3. Flash Memory
4. Cloud Services
5. Magnetic Tape

Optical Storage

Just a few years ago, CDs and DVDs were one of the most popular methods for storing large amounts of data – particularly among home users. This was a consequence of the relatively high prices of HDDs and particularly SSDs, as well as their limited capacity. In comparison, optical discs were competitive both in terms of price and the capacity they offered. Manufacturers declared relatively long lifespans, although these claims were quickly verified in practice. Depending on the manufacturer, a disc should serve from anywhere from 25 to 200 years, but that claim depends on so many factors. You should be prepared that the disc may become unreadable at any time – and rather sooner than later.

Our own behavior is the main reason for shortening the lifespan of a disc. Keeping them under wrong conditions, scratching, greasing (all of us have left our full sets of fingerprints on CDs) are common issues. In addition, lifespan can also be reduced from the methods used by manufactures to cut costs. Low-quality materials used to produce and protect the disc reduce the layer thickness, thus accelerating oxidation of the reflective layer.

All that aside, the hardware we use to read those discs may also turn out to be a problem. New computers often don’t have a disc drive, and even if they do, not all formats are supported (CD-R, CD-RW, DVD-RAM, DVD-R, DVD+R, DVD-RW, DVD+/–R DL). Each of these formats indicates a separate technology and an individual method of data reading, so it may turn out that soon you won’t be able to get hold of an appropriate reader for your disc.