How to allocate space from 1 disk to another

[omega3111]

Below is my SSD setup (please ignore the removable disk).

The 50GB unallocated space is what the Samsung Magician software recommended.

1. I would like to allocate the G partition (disk 0) to extend the D partition (disk 1). Is that possible to do?
2. I might want in the future to allocate more space from C to G. Is that possible?

 

[Sylvvester]

No. There are some methods to do that, but I wouldn't recommend them.
If you need to use space on C: or G: for files that are on D: then use symbolic links. I do that with Steam if I run out of space for games and it works perfectly. Read this: https://www.howtogeek.com/howto/16226/complete-guide-to-symbolic-links-symlinks-on-windows-or-linux/

 

[Colif]

It seems odd you have 168gb as RAW format, you should at least format it so its not RAW,

You can't resize G and add extra to C for same reason you can't make G any bigger as the only way to make a partition bigger is if the space is behind the partition you want to expand

Samsung would have kept that 50gb as unallocated so it can use it for error correction and over provisioning. Makes ssd last longer.

 

[Solandri]

From the size, I assume these are SSDs? You need to keep some space free on a SSD to maintain write performance. The usual recommendation is about 15%, but given the size of your SSD (500 GB) I can see why Magician went with 10%.

A HDD can overwrite data with new data directly. 0->1 and 1->0. A SSD must first erase the NAND cell before it can rewrite new data to it. 0->erased->1, 1->erased->0. If you remember the old EEPROMs, it's basically the same thing. The erased->0/1 step is blazing fast. The 0/1->erased step is really really slow. As slow as or slower than a HDD.

Consequently, SSDs pre-erase unused memory cells during idle time so that they're ready for blazing-fast writes. That's what TRIM was all about. Normally a filesystem "deletes" a file simply by changing the first byte in its name. So to the SSD, the data looks like it's still present, the filesystem just knows the space is free for writing new data. TRIM is how the filesystem tells the SSD the space is safe to erase. Newer SSDs recognize common filesystems and how they denote deleted files, so aren't as reliant on TRIM when it comes to erasing deleted files.

If you run out of pre-erased space on a SSD, then each time you write new data, the SSD must first erase the old (deleted) data before writing the new data. 0/1->erased->0/1. And it will slow down to the speed of a HDD or even slower. To avoid this, it's recommended to always leave some free space on the SSD. That gives it some room to pre-erase memory cells so they're ready for blazing-fast writes. And that's why Magician left about 10% of your SSD unallocated.

Unless you have the self-discipline to not fill up your SSDs and leave about 10% free on each one, I would just leave everything as-is, and not use that unallocated space.

If this is a TLC drive (EVO series), then the SSD also uses some of that space as a write cache. TLC writes (3 bits per memory cell) are pretty slow, so the drive first writes new data as MLC (2 bits per cell) or SLC (1 bit per cell). Then during idle time it re-writes that data in TLC mode. Without free space, it'll be forced to write directly in TLC mode.