Think you could ramble about hard drives? I think your old blog was actually what got me to buy my first HDD
oough yeah OF COURSE I can ramble about hard drives!!!!! i could ramble for days about hard drives. but I’ll spare you that, and stick to a particular subtopic instead
let’s talk about CMR and SMR! what these terms mean, what the differences are between them, and why it’s important to know which your HDD uses before you buy it!
HDDs, or hard disk drives, are data storage devices that have moving mechanical parts.
In HDDs, data is physically recorded using magnetic tracks on the disk.
CMR and SMR are both different methods for writing data onto an HDD.
There are pros and cons to each, and you’ll have to choose one based on what’s best for your use case, so let’s go over the differences!
CMR (Conventional Magnetic Recording)
CMR, or Conventional Magnetic Recording, has been around longer as a means of writing data to hard disks.
On a CMR drive, data is written side-by-side, with small gaps in between to avoid overlapping.
With CMR, you can rewrite data to an existing track without affecting the tracks around it. This helps with random read/write operations, as opposed to writes that happen sequentially.
The general consensus amongst datahoarders and other such tech nerds is that CMR drives should be used for servers. This is because they excel at handling high transfer rates and moving around large amounts of data.
SMR (Shingled Magnetic Recording)
SMR, or Shingled Magnetic Recording, is a relatively new technology for writing data to HDDs.
In SMR drives, data is written sequentially onto a track. Then that track is partially overlapped over another track of data, creating a pattern similar to the shingles on a house roof:
By removing the gaps previously found in CMR drives, SMR drives increase their storage capacity by utilizing more of the disk’s magnetic surface.
In general, SMR drives shine when used for backup and archival purposes, as infrequent drive access allows stable drive performance at a lower cost.
However, the overlapping tracks in SMR hard drives means that every time new data is added, old data gets overwritten. To keep that data from being permanently lost, the hard drive has to add it again.
This overwriting process takes time, and if the SMR hard drive has a lot of big files to store, it can spend a lot of time writing and rewriting data which can ultimately affect performance.
To keep SMR hard drives from becoming too slow, they need downtime to complete the rewriting process. Thus, they are generally less efficient for servers and/or other processes that are constantly reading and writing data without significant or reliable pause.
if you’re using your hard drive primarily to backup data and you won’t be messing around with it much once it’s archived, SMR can save you a few bucks. but if you’re running a server or otherwise have need for a lot of read/write operations without much downtime, go for CMR !
