In Digital storage world, "Data Archiving" is not an unheard word, but people often mistook Data Backup and Data Archiving as same. Many of the users are still using these words for the same reference, even if there’s an obvious difference.
SNIA (Storage Networking Industry Association) defines both terms as follows:
Backup: A collection of data stored on (usually removable) non-volatile storage media for purposes of recovery in case the original copy of data is lost or becomes inaccessible; also called a backup copy.
Archive: A collection of data objects, perhaps with associated metadata, in a storage system whose primary purpose is the long-term preservation and retention of that data.
In simple words, Backups are being kept for instant recovery of operational data while archiving stores the data that’s no longer needed frequently.
But backups as you know, are being used to protect changing (active) data on a frequent basis. When this active data gets lost or become inaccessible, we’ve to go for smart recovery tools – unless we don’t have the backup of those files.
In the case of archiving, no change is happening to original data. The speed of restoration is not at all a major concern one who goes for archiving data. Instead, there’re some important factors like searchability and data retention.
Simply saying, an active archive is the collection of data that is very important for a company/individual, but only have to access infrequently. But when the term active archiving comes, things will change. Then, it would be storing most frequently accessed files in fast media devices like SSDs and, storing less frequently access files in slower media devices like hard drives or optical media.
Various Forms of Data Archiving
One thing is sure – today’s storage media won’t last forever.
Before these terms becoming popular, backup process was just making a copy of data and putting it somewhere- maybe in the same hard disk drive. Those days are over - a lot of media storage devices are available now.
Optical storage devices such as writable CDs, DVDs, and Blu-ray discs can be an ideal medium for data archival up to some extent. But some questions on their reliability have to be answered as well. A normal CD-R cannot hold more than 700 MB of data while for DVD, it’s 4.7 GB.
Also, CDs and DVDs are increasingly following the way of the floppy. Newer PCs are less likely to have a CD/DVD drive. So, with new technologies like Blu-ray gets prominent in optical storage, you may have to shift your gear towards those.
Theoretically, write-once BD-R HTLs are said to be last more at least 100 years. For Milleniatta’s M-Disc BD-R, this duration is up to 1000 years!
Blue ray disks are available in 25, 50 and even 50 GBs. Their higher cost can still be a problem. Also, the speed of data access is relatively slow as compared to hard drives and SSDs. Leaving these limitations, optical storage can be a good choice for archiving.
Online storage services like Dropbox, iCloud, Microsoft OneDrive, etc. are comfortable for your data archiving, if you really trust them.
Of course - these services are easy to use, can be accessed from anywhere, etc. But, also you’ve to aware of the drawbacks of these techniques. While thinking about your secure data on the “cloud”, you’ve to understand – it’s stored in some unknown place. Your access to the data on the cloud will entirely depend on the speed and availability of your network connection.
Also, the prices for cloud subscription hasn’t reduced beyond a level, even there are exceptions like Amazon’s Glacier.
So as I said in the intro - if you really trust cloud services, you can use them. Otherwise, local storage will be fine.
In an enterprise environment, tape drives are still on the discussion table. There are tape drives that can hold more than 100 TB of data. It’s removable also.
At the same time, there’re many disadvantages to reveal. It’s very costly, the speed of data access is very less, also it can easily get affected by physical or magnetic wearing. So, for consumers, tape drives cannot be suggested for data archiving.
Portable Hard Drives
Choosing portable hard drives for data archiving is not an ideal choice, but it’s convenient in terms of price-speed of access. Perhaps, for the consumers, this would be the most commonly used medium for data archiving.
Limitations of portable hard drives as data archiving medium starts from some questions on its durability. Since being magnetic, it’s data retention properties are likely to diminish drastically over years – more evidently than optical storage. It’ll be hard to maintain these drives also.
So, if you are using portable hard drives for data archiving, you may need to replace the drive during the course of five-six years.
Theoretically, SSDs are shock proof and durable. But, there are still uncertainties about data storage capabilities of NAND flash drives. Cost is also comparatively high. Also, it’s not sure how long an SSD can store data when it’s left idle and unpowered.
But, flash drives if uses in normal conditions have maintained data for about ten years. So, if it’s an affordable option, you can think about it.
Different Archiving Strategies Users Can Follow to Protect Data
Strategy 1: If you’ve done adding data to your re-writable media, you can write-protect it – to prevent accidental overwrite. Using Diskpart utility, you can write protect hard drives with the command “att vol set readonly” and can be removed this write protection by replacing “set” with “clear”.
Strategy 2: You can consider of encrypting your archives if you’re confident enough of the passwords you’re using. These passwords can be lost or forgotten. But, if the data is too sensitive, you have to think about encrypting it.
Strategy 3: It’s better to avoid proprietary file formats for saving archives. In future, some of these file formats will tend to become unreadable. For compression, the format should be universal like ZIP.
Strategy 4: Use different storage medium for storage different copies of the same file.
Strategy 5: Don’t create archives from unfinished data. Make sure that your data is final and that doesn’t require any change before preparing archive from it.
Let you might be less concerned about your data until this moment. If there’s any change in such an approach after reading this article, it’ll be an honor for me.
Protect your data by archiving it.
Hope, you’ll do that.