Rather than relying on traditional hard drives in individual computers, a growing number of businesses are moving to network attached storage, or NAS, devices for their data storage needs. Newer NAS devices utilize SSD caching to improve performance. Does your NAS need this feature?
First, a little background: a NAS device allows you to store just about any data onto one centralized system so that it can be accessed by anyone connected to your network (as long as they have permission to do so). Unlike a traditional computer hard drive, NAS devices typically use RAID (Redundant Array of Independent Disks) technology to ensure data won’t be lost even if a drive fails. In addition, as the data storage needs increase, companies can add additional drives to the NAS to increase capacity.
There is no doubt that NAS is a great solution for companies of all sizes. In some cases, however, the performance of a NAS is not as responsive as users would like. If you want to boost the performance of your NAS, turning to solid state drives (SSD) for caching may be a great option. Learn more about how SSD caching improves NAS performance to see if it is a good option for you.
What is NAS Caching?
NAS caching is an option that allows specific files to be stored in a part of the system that performs the best. This logic allows the most commonly accessed files to be stored in a way that will enable them to be retrieved most quickly. An example of caching is when you access a website; the site may save specific files to your local computer so that the next time you load the page, it populates more quickly due to previously saved files.
Since the files on a NAS system can be updated by multiple users, it generally doesn’t make sense to save a file off to the end user’s computer. So instead, the caching is done locally on the NAS device. Depending on your NAS type, you can use various kinds of storage for your caching, including solid state drives.
Solid state drives are far faster than traditional hard drives. This increased speed makes them the ideal place for files that are accessed frequently by many different people. NAS technology allows the system to track which files are accessed the most and cache them onto the solid-state drive in order to improve performance. The NAS device can be set up to continuously monitor how often each file is accessed (and how long each file takes to load) so that it can adjust which files are cached at any given time.
How Can SSD Caching Improve Performance?
To put it simply, SSD caching improves the performance of your NAS by placing frequently accessed files onto a solid-state drive rather than a traditional hard drive. Since modern NAS systems can be configured to automatically ‘learn’ which files are accessed most often and cache them on the SSD. This way, when someone accesses that file, it will load much more quickly. In addition, this helps to free up the read/write processes on the traditional hard drives so they can respond to requests faster.
When setting up SSD caching for your NAS, you will have three main options to consider. Each of them will have distinct advantages and disadvantages to be aware of:
- Read Only SSD Caching – With this option, the NAS places a copy of a frequently accessed file onto the SSD as a read-only file. Anyone accessing the file will load it off of the solid-state drive. If they need to manipulate the file and save it back to the NAS, it will save onto the traditional hard drives. The NAS will monitor for changes to the file on the hard drives and update the read-only file on the SSD as needed. This option is faster than skipping caching but is still the slowest of the SSD caching options. In addition to the speed boost, this option also helps ensure updates are not lost during an outage because they are written directly to the hard drives, already protected through the RAID technology.
- Write-Through SSD Caching – With this option, a read/write copy of a popular file is made on the SSD. Anytime a user changes that file, the copy on the SSD will update. At the same time, the copy on the hard drive also updates. This dual copying ensures the changes are not lost during a power outage or drive failure. Write-through SSD caching is a significantly faster option than the read-only SSD caching, but still not as fast as the next solution.
- Write-Back SSD Caching – This option is similar to the write-through SSD caching in that files on the SSD can be written over. The difference is that a change occurs to the file and is then saved exclusively to the SSD cache first. Only after it is confirmed that the data on the SSD has been completely saved before it sends the updated file back to the hard drive. This process can put the changes at risk of loss during a power outage or drive failure, especially for larger files that can take some time to save in their entirety. Since the users never have to wait for the hard drive, however, it is the option with the best performance.
Please note that the technologies above are described accurately but simplified.
Downsides of SSD Caching on a NAS
The main downside of using solid-state drives for caching on your NAS is that solid-state drives are significantly more expensive than traditional drives. Fortunately, you will only need a fraction of the amount of storage space for caching compared to the entire NAS. A common strategy is to have one (or more) solid-state drives that make up about 10% of the total storage on a NAS and use them for caching. Note also that you do not need to set up the SSDs using RAID configuration, so you only need one physical SSD for your NAS in most cases. Learn more about how to choose the right SSD drive here.
Is SSD Caching for Your NAS Worth the Investment?
Each company will have to look at the performance of their NAS and the expense of upgrading to an SSD for caching to see if it is worth it. The cost of solid-state drives has decreased significantly in recent years, so this is seen as a wise investment for many businesses. It is especially popular for small to mid-sized companies that do not have massive storage needs since a modestly sized SSD is highly affordable. For these reasons, most industry experts would agree that using SSD caching for your NAS is an option that makes sense.
