When it comes to computer storage, there are different types of disks that can be used. Some disks have the ability to be extended or expanded upon when more storage space is needed, while other disks do not have this capability. Knowing which disk types can be extended is important when planning for future storage needs.
Hard Disk Drives (HDDs)
Traditional hard disk drives (HDDs) with spinning magnetic disks can generally be extended. HDDs connect to a computer via SATA, SAS, or USB connections. As long as there is an available connection port and the disk controller supports it, additional HDDs can be added to a system to expand the total storage capacity. HDDs are still very common in desktop PCs, servers, NAS devices, and external storage drives.
For internal HDDs in a desktop PC case, there are usually open drive bays where additional HDDs can be mounted. In servers and external enclosures, there are typically empty hot-swap drive bays ready to accept new drive installations. Capacity can be expanded one drive at a time, or in some cases multiple drives can be added at once if there are enough open bays and ports.
Pros of Expanding HDD Storage
- Inexpensive cost per GB for high capacities
- Ability to add small capacity increments as needed
- Hot-swappability makes expanding easy in servers/NAS
Cons of Expanding HDD Storage
- Slower performance than SSDs
- Older/cheaper HDDs tend to be less reliable
- More points of failure with multiple drives
Solid State Drives (SSDs)
Unlike traditional HDDs, solid state drives (SSDs) with flash memory chips typically cannot be easily extended. This is because SSDs usually connect via an internal SATA or PCIe port, neither of which can be easily expanded in a computer system or external enclosure.
However, there are a few ways SSD storage can be expanded:
- Add individual SSDs to open drive bays and ports, then combine their capacity into a single volume using RAID 0.
- Upgrade to a higher capacity SATA SSD of the same physical size.
- Upgrade to a higher capacity PCIe SSD, which may be an add-in card or M.2 stick SSD.
- Use an external SSD enclosure to add more flash storage via USB or Thunderbolt.
The main limitation is that SSDs cannot typically be daisy chained like HDDs. Each one connects to a single endpoint on the PC or enclosure.
Pros of Expanding SSD Storage
- Very fast performance from flash memory
- No moving parts – more reliable and durable
- Small physical size of M.2 and 2.5″ SSD formats
Cons of Expanding SSD Storage
- More expensive per GB than HDDs
- Limited options for connecting multiple SSDs
- Reaching capacity limits requires replacement
Hybrid Drives
Hybrid drives, also known as SSHDs, contain both flash memory and a traditional spinning disk in a single drive unit. They aim to provide some of the performance benefits of an SSD with the capacity potential of an HDD.
Most hybrid drives cannot be easily extended, as they are designed as self-contained units. However, some NAS systems and external enclosures allow installing multiple hybrid drives and managing them in a single volume.
Overall, hybrid drives are less common now as SSD prices have decreased. All-flash storage provides consistently better performance than hybrid options.
Pros of Expanding Hybrid Storage
- Moderate cost per GB
- Built-in flash improves performance over HDDs
- Can add multiple hybrid drives for more capacity
Cons of Expanding Hybrid Storage
- Performance is still slower than pure SSD options
- Limited flexibility for incremental expansion
- Unsure lifespan of flash portion
RAID Arrays
RAID (Redundant Array of Independent Disks) allows multiple drives to be combined together into a single logical volume. This can be used to expand overall storage capacity, add redundancy, or improve performance.
A wide range of RAID levels are available, indicated by a RAID number from 0 to 10. Each has different advantages for things like capacity, speed, and fault tolerance. For example, RAID 0 stripes data across all the disks for maximum capacity and speed but has no redundancy. RAID 1 mirrors two disks for fault tolerance, using 50% of total capacity. And RAID 5 stripes data across disks with distributed parity for both extra capacity and redundancy.
RAID arrays can be created from multiple HDDs, SSDs, or even hybrid drives, depending on your performance and capacity needs. The drives connect to the RAID controller either internally via drive bays and backplanes in a server or external enclosure, or in some cases externally through USB/Thunderbolt multi-drive enclosures.
Pros of Expanding with RAID
- Add capacity, redundancy, and/or speed
- Support combining multiple drive types
- Scalable by adding drives to array
Cons of Expanding with RAID
- More hardware complexity
- RAID controllers can be expensive
- No direct access to individual drives
Network Attached Storage (NAS)
Network attached storage (NAS) devices are specialized appliances designed for storing and sharing data over a network. They typically consist of multiple internal hard drives that can be expanded as needed by adding more drives.
Most NAS units have open drive bays to support expanding storage. These are often hot-swappable, allowing new HDDs or SSDs to be slid into place without powering down the NAS. After installing new drives, the NAS operating system detects the increased capacity and automatically expands the storage pool or volume that it provides to clients.
In addition to adding drives internally, some NAS appliances support attaching external drives via USB or eSATA ports. This allows easily connecting temporary or permanent external storage expansions.
Pros of Expanding NAS Storage
- Designed for easy drive expansions
- Hot-swappable drive bays
- Automated storage pool expansion
Cons of Expanding NAS Storage
- Internal capacity limited by physical slots
- External expansions may have limited performance
- More potential points of failure
External Storage Expansion
One of the easiest ways to expand storage is by connecting external drives via the various interface ports available on desktop PCs and laptops. Common external drive interfaces include:
- USB – The most common port for connecting flash drives, portable HDDs, and SSDs.
- Thunderbolt/USB-C – Supports daisy chaining high performance external drives.
- eSATA – Interface for attaching fast desktop external HDDs.
With these interfaces, it’s simple to connect an external drive and instantly expand your available storage pool. And it’s easy to disconnect them or switch them between systems as needed. Individual external drives can be combined into multi-bay enclosures for even higher capacity.
Pros of External Drive Expansion
- Simple plug and play connection
- Portable between systems
- No internal drive installations needed
Cons of External Drive Expansion
- Extra cables and power supplies
- Typically lower performance than internal drives
- Requires available USB/Thunderbolt ports
Cloud Storage
Cloud-based storage services offer another approach to getting more capacity without local hardware expansions. Services like Dropbox, Google Drive, Microsoft OneDrive, and Amazon S3 allow you to store files on remote servers.
Most cloud services start with a free tier offering 5-15 GB of capacity. Paid monthly subscription plans range from 100 GB up to several terabytes or more. The benefit is you can store as much as you need without worrying about local drive limitations.
Cloud storage is accessed through desktop/mobile apps or web interfaces. Files are cached locally and synced to the cloud automatically. Cloud services are ideal for backup, archiving, and sharing files online.
Pros of Cloud Storage Expansion
- Virtually unlimited capacity
- Access files from anywhere
- No hardware to maintain
Cons of Cloud Storage Expansion
- Monthly subscription fees
- Dependent on internet connection speed
- Less control than local storage
Conclusion
There are a variety of options for expanding storage capacity beyond the built-in drives in a computer system. The ability to extend system storage depends on both the type of drives used and the interfaces available. HDDs and NAS appliances are inherently designed for expansion by adding more drives.
SSDs offer many performance benefits but have limited expandability in most consumer devices. However, external SSDs can connect via USB/Thunderbolt ports to add flash storage. RAID arrays allow combining multiple internal drives into larger volumes.
For the simplest storage expansion, external USB hard drives and flash drives can easily connect to empty ports. And for unlimited capacity without local storage, cloud services may fit the need. Overall, with careful planning and the right hardware selections, storage can be expanded to practically any size needed.