Hey Dave! How do I defrag a ssd drive? Does it affect performance if don’t defragment the drive occasionally on my Windows PC?
The short answer is no, you don’t need to do anything to defragment your solid-state hard drives on your computer, whether you’re running Windows, Linux or MacOS X. But let’s dig into this so you understand why this is the case.
To start, fragmentation occurs because every file on your computer system is actually a linked chain of “blocks”, typically 1K bytes to 2K bytes. FAT32 on Windows, for example, uses file blocks called “fragments” that are somewhere between 2 KB and 32 KB in size. To store a 1MB file with 2KB blocks or fragments therefore requires a chain of around 500 blocks. Each block typically includes the address of the next block in the chain, so you can see where if any link gets corrupted, the entire file is all borked up.
With a brand new hard drive, these blocks are contiguous to maximize performance; with a physical hard drive, there’s a read head that has to wait until the correct spot on the drive platter is available to read the contents. As you use the disk more, however, files are created, chained, deleted, resized, expanded, contracted, copied, etc. Pretty soon that neat block1 -> block2 -> block3 sequence becomes far more convoluted, and block351 -> block71314 -> block11 becomes the order of the day. With a physical drive, this can become inefficient and slow as the drive keeps waiting and waiting for the next block in a file to be available to read.
To solve that problem on a standard drive, there are defragmentation or just defrag utilities that will find the most fragmented files on your system and fix them. It does this neat trick by copying the file into a new big block that has lots of adjacent blocks. Then the old highly fragmented version is deleted, everything looks 100% identical to you on the drive, but it’s faster.
Which brings us to solid state drives or SSDs. Instead of imagining a physical magnetic disk spinning at a super fast rate, these are more like a ton of RAM memory chips jammed into a tiny box. Which means there’s no physical “read” process and the drive never has to wait to get the read head from one point on the disk to another. In this world block351 -> block71314 -> block11 is exactly as fast to access as block1 -> block2 -> block3.
Ergo, no need to defrag because your files can’t become fragmented.
There’s also something called TRIM in modern operating systems that let them work more efficiently with SSD drives: TRIM “allows an operating system to inform a solid-state drive (SSD) which blocks of data are no longer considered in use and can be wiped internally”. There are, of course, programs you can purchase that purport to speed up SSD drives by defragmenting them, but PC World found that none of the four they tested did much of anything in real world trials.
Suffice to say, you can ignore the problem with your solid state drive. If you’re paranoid and skeptical both, you can always get a spare physical drive, copy the entire SSD’s contents onto it, reformat the SSD and copy everything back. But you’ll just be mostly wasting your time with that rather tedious process.
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