One of your biggest concerns as an IT professional is determining what type of storage to use and for what types of data use cases – mobile applications, databases, websites, files, or backing up mission-critical data. Odds are that you will probably use a combination of data storage types to meet the needs of your users and the requirements of your data.
Data storage is used for a multitude of reasons. If you’re developing an application, you may have users that upload documents, photos, videos or other files. You’ll need somewhere to store user files. If you’re a developer, you may use a content delivery network (CDN) and data storage to increase load speed, availability and reliability. If you’re in charge of IT, your main concern may be storage and backup for disaster recovery and business continuity.
Understanding data storage is not hard but all of the different types and options can be confusing, especially if you're not an IT professional. In this article, we will discuss the different types of data storage along with the advantages and disadvantages of each plus use cases.
Direct Attached Storage (DAS)
Most people are familiar with direct attached storage (DAS) whether they know it or not. This is because most have already used it. In fact, if you have a laptop in front of you, there’s a DAS hard drive within that laptop. It’s called direct-attached storage because it is directly attached. DAS could also be an external hard drive or thumb drive to a computer, laptop or tablet.
Advantages of Direct Attached Storage (DAS)
What are the benefits of DAS? Direct attached storage is great because it's very cheap and very easy to use. In fact, you can purchase a 6TB external hard drive for as low as a few hundred dollars. DAS is extremely cheap for what you're getting. The price per GB is very low and pricing continues to trend downward for these types of storage devices.
Disadvantages of Direct Attached Storage (DAS)
What’s the downside of direct attached storage? The main downside to DAS is that it is not very shareable. If you wanted to share your data with someone else, you would have to either upload it from your computer or laptop to the cloud, send through email as an attachment or physically go over to that person's computer to share it.
DAS is definitely not useful in all business cases. This is one reason why direct attached storage is not used in cloud environments. Can you imagine your employees walking around with external hard drives and plugging them into virtual machines or the servers that they're running in their data centers?
Network Attached Storage (NAS)
The next data storage type we are going to discuss is network attached storage (NAS). Many descriptions of NAS make it seem like it is very complex. However, it’s really not that hard to understand. There are three basic components associated with NAS.
First, NAS has to have connectivity to the internet and to a local area network (LAN). Second, you must have multiple hard drives attached to the NAS. Third, the hard drives have to be configured into what we call a RAID configuration. RAID is a redundant array of independent disks – hard drives are setup to replicate the data in various ways.
What’s an example of RAID? Let’s say that you have four hard drives and two of them are replicated amongst each other. The other two are replicated amongst each other. You set those hard drives up to store data independently. It may be partially replicated or fully replicated. With RAID, you have the assurance that if one of the drives fails, you're not going to lose all of your data.
Advantages of Network Attached Storage (NAS)
Although network attached storage NAS is more expensive than DAS, it's still pretty cheap. Further, network attached storage is great for collaboration. For example, let’s say that your company has a lot of files and numerous employees working on those files, NAS could be the right data storage type for your business.
A use case would be a business with 10-50 employees that all need to access and edit files on the same hard drive. NAS is perfect for that scenario because when you see it on your computer, it'll show up as a single file on the shared drive.
NAS provides centralized control of all the files. You’re able to set permissions on who can see what in the network. And finally, as we talked about earlier with the RAID configuration, you can replicate data and make sure that you have backups of that data.
Disadvantages of Network Attached Storage (NAS)
Performance can be a major issue for NAS. This means that if you have a lot of activity on your network, it's going to slow down the performance. Further, with low throughput and high latency, a NAS is not fast enough for high-performance applications.
NAS can also be limited from a scalability perspective. NAS is limited to its own resources and you can only scale by adding another NAS. This becomes even more complicated with NAS sprawl – too many devices.
Storage Area Network (SAN)
What is a storage area network (SAN)? Simply put, a SAN is a high-speed network that provides block-level network access to connect servers to their logical disk units (LUNs). LUNs consist of a range of blocks provisioned from a pool of shared storage and presented to the server as a logical disk. Server partitions and formats those blocks with a file system so it can store data on the LUN just as it would on local disk storage.
SANs make up about two-thirds of the total networked storage market. They are designed to remove single points of failure, making SANs highly available and resilient. A well-designed SAN can easily withstand multiple components or device failures.
However, SANs are fairly complex infrastructure with hosts, switches, storage elements, and storage devices that are interconnected using a variety of technologies, topologies, and protocols. Storage area networks may also span multiple sites or locations.
Advantages of Storage Area Network (SAN)
There are numerous benefits associated with storage area networks. SANs are often used to improve application availability with multiple data paths. SANs enhance application performance such as off-loading storage functions. They also increase storage utilization and effectiveness by consolidate storage resources and provide tiered storage.
Disadvantages of Storage Area Network (SAN)
There are a few disadvantages to the storage area network (SAN). First, SANs are very expensive. It's not ridiculously expensive if you're using it for cloud computing. However, if you try to set it up on your own, it's going to be very expensive. SANs are also complex and difficult to setup. That would be the downside. However, it’s probably one of the more common types of storage that you'll see in cloud computing.
What is block storage? If you look at a hard drive, it’s basically a block storage device. This means that the hard drive is broken up into partitions which is stores files on a file system in as little as 512-byte blocks. For example, you can run the EXT4 file system on partition one and three which is basically the Linux file system. You can run an Apple based file system on partition two and a Windows NTFS file system on partition four. That’s block storage in a nutshell.
If you're running Windows, you could access this partition for all of your Windows files. For example, you have a Microsoft Excel file that is 200 kilobytes or 200,000 bytes. If each block is 512 bytes, this particular Excel file requires about 62 ½ blocks.
One of the best things about block storage is that when you edit your Excel file, maybe you make changes to cells 1-84. It’s going to affect a few blocks within that entire file. If the file is 62 ½ blocks, you only have to edit four of them. When you save the file, it's going to only find the four blocks that it needs to edit. You don't have to replace it all at once so this makes block storage very efficient in that way.
Advantages of Block Storage
There are many benefits associated with block storage. First, their numerous programming languages can easily read and write files on block storage. Also, permissions and access controls for block storage are familiar and well-understood. Lastly, block storage provides low latency IO so they can be used with databases and dynamic data.
Disadvantages of Block Storage
There are also several disadvantages of block storage. Block storage is limited to one server at a time which impacts scalability. Further, blocks and filesystems have limited metadata about the information they're storing such as creation date, owner, size and more. Another major disadvantage of block storage is the cost structure. With block storage, you must pay for all of the block storage space you have allocated even if you are not using it.
The last data storage option we will be discussing in this article is called object storage. Object storage is very different from other storage types we've talked about. In fact, it's in a whole different realm. It's also a newer type of file storage and therefore it works differently.
First, you have objects rather than files or blocks. Essentially, you have unstructured data objects that have three parts. They have an ID. They have metadata such as the authors of the file. They have the date that the file was created, permissions on the file, so on and so forth.
Imagine you have a large quantity of unstructured data. It could be a picture or a large video file. Every time you update that file, you have to add the entire file. If you want to make any changes to your video you would have to create an entirely new object and you could have different versions but completely different files or objects. With object storage, you can't do piecemeal operations and it is best for very specific use cases – including storing lots of unstructured data.
With object storage, you write once and read many times. An example of this would be YouTube videos. Once an author uploads it, they really can’t edit it and they can’t change it much. That's a perfect use case for object storage. If you want to edit it, the user must upload a new video and delete the old one. You could also keep different versions of the same video file with slight variations which is versioning.
Advantages of Object Storage
There are many benefits associated with object storage including scalability. It’s widely known for its compatibility with the cloud and that’s because it has unlimited scalability. Because of its flat structure, object storage doesn’t have the same limitations as file or block storage.
Object storage has faster data retrieval and better recovery than other types of data storage. With object storage, there’s no need sift through file structures which means faster retrievals. The metadata allows for quick access and fewer limitations.
Lastly, object storage is known for being cost-effective. Because object storage scales out much easier than other storage types, it’s less costly to store all your data.
Disadvantages of Object Storage
Are there disadvantages to object storage? Yes, object storage isn’t right for every use case when it comes to data storage. In fact, you can’t use object storage for traditional databases. It’s only great for static data.
Another disadvantage of object storage that we discussed was that it doesn’t allow you to alter just a piece of data. You must read and write the entire object at once.
Which Data Storage Type is Right for Your Business?
The answer is that it really depends on your specific use case and business requirements – data, users, access types, budget, applications and more. Most likely, you will use a combination of data storage types such as DAS, NAS, SAN, block storage and object storage. Most likely it will be block or object storage in the cloud.
The first step in determining which data storage type to use is to evaluate your data and how your users access that data and how often. Then, create an IT infrastructure strategy that incorporates the best data storage type based on those requirements.
Datacenters.com can help you evaluate your IT infrastructure from a physical and virtual perspective. Contact us today to learn more about how we can help you architect your business for the future.
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