When you read the specs sheet of your new laptop or your new server or a storage system, the words “Flash, NVMe, or even No moving parts” keep recurring and seem to be the new buzz. We are being promised a lot of performance with read and write speeds that are five times or 10 times faster than what we currently have. To what extent is this really true? Let’s dive in.
The most common unit used to measure the performance of storage drives is IOPS (input/output per second). This is a great unit because it provides a simple way to know how much data can be read/written onto the drive at any given time (measuring speed and latency). This means that a drive with 100 iops is slower than a drive with 1000 iops. So, if you have a machine with a drive that gives you more iops, that machine is indubitably faster. Is that all there is to know about drives then?
Before I can provide an answer, let’s look at the different type of drives that are available.
Hard Disk Drive
This is the most commonly used drive type at the moment, commonly abbreviated HDD or just Hard Disk or Hard Drive. HDDs use platinum disks to store computer information (bits 1s or 0s) in a magnetic form. Each platinum disk called platters is divided into circular “disks” called tracks further subdivided into smaller chunks called sectors. Sectors are then labelled, and a journal maps data location to the corresponding sector. This is called an Address which is used to retrieve/overwrite/delete the data when needed. On top of each platter there is a head; the head converts computer information into magnetic form (and vice versa) and is primarily responsible for reading and writing the data; the head is fixed on an actuator arm to move it around. Also, when an address is sought the platter rotates to position itself for the head. This means the rotational speed of the platter and the speed of the actuator arm affect the speed of the drive as they determine how fast the address is accessed. HDDs fail often because of the head and dropping an HDD permanently damages it, especially when the head scratches the platter because of the shock (the head never touches the platter it hovers over it to read the magnetic data).
Figure 1 – HDD Components (left) and Tracks and Sector (right)
Solid State Drive
We looked at HDDs with their seek time and rotational time which affect the data access. Now let’s look at Solid State Drives called SSDs or Flash Drives. Data on SSD is stored in a semi-conductor much like it is stored on your typical memory or pen drive. This means the data is accessed from a grid (the address) similar to columns and rows. That means we are getting read of all the mechanics that must happen to access addresses and just retrieving them using electrical access. This is one of the reasons SSDs are much faster than HDDs. There are two main types of SSDs i.e. SATA accessed and NVMe accessed. NVMe drives are faster than SATA drives as the former connection was built specifically to access faster SSD drives.
Figure 2 – NVMe (left) and SATA SSD (right)
Also note that SSDs come optimized for intensive read, intensive write or mixed purposes depending on the intended purpose. SSDs do not fail often because there is no mechanical moving components.
Are SSDs the best to store any and every data then? Well not necessarily. Here is why:
Type of IOPS
IOPS can be categorized using attributes such as random or sequential coupled with large or small. The type of storage required for small random iops is not necessarily adequate for large sequential iops. Storage manufacturers advise putting large sequential iops on HDDs and small random iops on SSDs. For more information on the type of iops you will be using, kindly check with the application vendor.
Well SSDs are the new thing and as usual, they are more expensive. It would be a complete waste to buy NVMe SSDs to store archive files or CCTV data. But it would be the best prospect for your most critical application database. It is now up to you to determine what is worth the price. I recommend you check how much each TB is costing you per Dollar ($) and you will be able to measure which application requires it or not.
SSD read and write speed average 100 times that of HDD; making the choice to go for one or another depends on the application or intended workload. Find the right balance and you will optimize cost whilst improving on responsiveness and workloads availability.
Apotica deploy hybrid cloud solutions for customers and is uniquely positioned to advice on your workloads against your storage needs (scoping and sizing). You can request for a free consultation here. To enquire about any equipment or software, call us on +233.54.431.5710 or write to firstname.lastname@example.org.
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