Your NAS isn't enough – you still need to back up your data!
Power Failure
Modern filesystems are moderately resistant to power failure, but even the mighty ZFS could suffer from a blackout [9]. A UPS will help, but beware of cheap units: Many budget domestic UPS are not prepared to handle continuous operation and will wear out, eventually bringing down the NAS with them. According to a Ponemon Institute's 2016 survey, UPS failure is the top cause of unplanned data center outages [10]. What this means in practice is that blackout protection reduces the risk of suffering data loss from power loss, but it does not remove the threat entirely.
In enterprise scenarios, administrators are aware that trying to make a NAS bulletproof is not enough to guarantee true high availability. In practice, the enterprise uses Storage Area Networks (SAN) or distributed filesystems such as Ceph [11]. Such tools are deployed in computer clusters, in such a way that if a server goes down, the rest of the cluster remains operational.
The minimal (and, for serious purposes, insufficient) storage cluster that can be deployed is described in Figure 7. This is known as a Primary-Replica topology, in which the primary performs services for the clients. The replica's contents are periodically synchronized with the primary's. Should the primary go down, the load balancer will promote the replica and turn it into the new primary (Figure 8).
The Cloud Option
Real life high-availability systems are not something you are likely to be able to run at home: typically they feature redundant load balancers and might require some Border Gateway Protocol (BGP) magic thrown in. Even the naive and simple method I just described multiplies the cost of the storage by more than two, because it requires a redundant server and a load balancer (at which point you are likely to need a server rack in a server room).
It is therefore not a surprise that many users, especially small businesses, turn to professional storage vendors, who offer cloud storage for a fee and take care of ensuring the storage systems are perpetually available. Professional storage vendors might also be very cost effective. For example, cloud storage might cost you around $1,500 in four years, which is less than what you are likely to spend on a good NAS. As I assume a NAS is likely to need an upgrade around the fourth year, the cloud option is not entirely unreasonable. Sadly, storage vendors come with their own issues: Uploading your data to them can take much longer than uploading it to a local server, and some vendor environments might present privacy concerns.
Humans and Software
Even if you were to assume that your chosen storage solution is completely indestructible, it would still not eliminate the need for a proper backup system. If you manually delete a file by mistake, or if you lost the file to a software bug or malware, it makes no difference whether it was stored on a regular laptop, a high-end NAS, or a cloud storage provider. Experience shows that human mistakes force you to restore from backups much more often than hardware failures. Certain storage vendors know this and keep a historical registry of every file uploaded to them, so you can retrieve an old version of a file if you discover you have uploaded a corrupt version or deleted something important by accident. Interestingly, the vendor is actually running a backup policy for you.
« Previous 1 2 3 Next »
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Linux Servers Targeted by Akira Ransomware
A group of bad actors who have already extorted $42 million have their sights set on the Linux platform.
-
TUXEDO Computers Unveils Linux Laptop Featuring AMD Ryzen CPU
This latest release is the first laptop to include the new CPU from Ryzen and Linux preinstalled.
-
XZ Gets the All-Clear
The back door xz vulnerability has been officially reverted for Fedora 40 and versions 38 and 39 were never affected.
-
Canonical Collaborates with Qualcomm on New Venture
This new joint effort is geared toward bringing Ubuntu and Ubuntu Core to Qualcomm-powered devices.
-
Kodi 21.0 Open-Source Entertainment Hub Released
After a year of development, the award-winning Kodi cross-platform, media center software is now available with many new additions and improvements.
-
Linux Usage Increases in Two Key Areas
If market share is your thing, you'll be happy to know that Linux is on the rise in two areas that, if they keep climbing, could have serious meaning for Linux's future.
-
Vulnerability Discovered in xz Libraries
An urgent alert for Fedora 40 has been posted and users should pay attention.
-
Canonical Bumps LTS Support to 12 years
If you're worried that your Ubuntu LTS release won't be supported long enough to last, Canonical has a surprise for you in the form of 12 years of security coverage.
-
Fedora 40 Beta Released Soon
With the official release of Fedora 40 coming in April, it's almost time to download the beta and see what's new.
-
New Pentesting Distribution to Compete with Kali Linux
SnoopGod is now available for your testing needs