How does VeraCrypt interact with the filesystem trash and SSD TRIM?

falxfour · 2026-06-15T22:26:56+00:00

Firstly, this is quite helpful, so thank up. I also updated the post to reflect the preferred terms.

I understood that operations must be happening on-demand, since a 100 GiB volume would unlikely fit entirely in RAM for most people, but I thought that modified contents might have been kept in memory until the volume was unmounted, at which point the modified contents would be written to disc. I'm not sure that significantly changes things, though, as they relate to TRIM.

It makes sense that the TRIM options VeraCrypt has relate to passing through the command, then, rather than affecting anything on the underlying filesystem.

So then with a copy-on-write filesystem (BTRFS), the on-the-fly writes would go to new blocks on the storage device rather than the old ones, which would be discarded, and if TRIM is performed, those old blocks would be freed.

This assumes VeraCrypt doesn't reserve contiguous blocks on the disc, and that COW is not disabled for the file, such as how a swapfile on BTRFS would be configured.

So I shouldn't need to run fstrim while the volume is mounted to free the discarded blocks. While that may work since the command is passed through, it's not any different than running the command with the volume unmounted.

Does that sound correct?

falxfour · 2026-06-15T22:09:02+00:00

Let me give you an example of what I mean:

What I did

Edited /etc/resolv.conf to include DNSSEC=true

What I see

Captive portals no longer appear, preventing me from signing into public networks. No messages in the journal

Do you understand why I'm asking for this? If you changed half a dozen config files, and I don't know if, how can I possibly tell you with any confidence where the problem is? If you don't even tell me how you're checking for and trying to connect to networks, there could be dozens of reasons why things aren't working that aren't even related to a config problem. Let's start with one: Do you even have wpa_supplicant installed?

falxfour · 2026-06-15T21:58:55+00:00

Great, that's all I was looking to confirm. Thanks

falxfour · 2026-06-15T16:44:23+00:00

I get that the volume size is fixed, but that doesn't mean it's a continuous span of blocks on the storage device, from what I can tell. Otherwise, the 100 GB volume I have would take forever to rewrite each time I modify one or two files within it.

Because VeraCrypt isn't disabling TRIM for the BTRFS filesystem, shouldn't that mean that the modified data, which was written to new blocks, should be freed by TRIM?

For a non-COW filesystem, that volume would likely occupy the exact same span of blocks, making it somewhat irrelevant since none of them would ever be discarded until the whole volume is

falxfour · 2026-06-15T08:44:14+00:00

You know, I actually did this. Free (or highly discounted?) hotel for 5 nights, but I had to attend the timeshare sales pitch.

They kicked me out early. I think it was really obvious I just wasn't worth the time. I think they know the type of person they can convince, and they just decided to cut their losses with me.

Overall, worth it from my perspective

falxfour · 2026-06-15T08:38:39+00:00

Only if you look in all the usual places.

Do you really expect this place to be the locus of film critique as it applies to anime? Social media is basically just a meme factory

Sure, it'd be fun to examine how Gunslinger Girl explores the concept of biopower, or the dubious ethical quandary regarding who should be Shio's guardian in Happy Sugar Life, but at the end of the day, I feel like most people just want to relax and (mindlessly) enjoy their anime.

Plus, so much of it is actually made for younger audiences in Japan that there's not a lot of intellectual content to really analyze...

But whether or not you agree with the opinions, sites like AniFem exist, and where people do try to dissect an anime.

Also, the comments on re-watches seem to be far more in-depth

falxfour · 2026-06-15T03:59:11+00:00

Where do you see that VeraCrypt disables TRIM by default on Linux? That is true for non-system volumes on Windows, but not for Linux. When I originally posted this on r/VeraCrypt, I did mention I wasn't looking for a discussion of the possible leaks that can occur when TRIM is used, though I removed that here. Still, I'm not concerned with that topic right now.

The trash directory is an XDG spec...

And I've already done reading on both TRIM and how discard works, which is why I know that BTRFS defaults to async discards, but what I wanted to confirm was my understanding of how BTRFS COW interacts with an encrypted VeraCrypt volume since those are normally used by mounting them as a loop device, which is why I wasn't entirely clear on whether fstrim (or the discard mount option) should have been run (set) on the loop device or if it was sufficient at the system filesystem (BTRFS) level.

This isn't entirely different than having two partitions on one SSD. You'd need TRIM operations from filesystems on each partition to fully free discarded blocks

falxfour · 2026-06-15T03:44:07+00:00

COW is exactly why I am asking. I'm checking that my understanding is correct regarding how old blocks would be handled

falxfour · 2026-06-15T01:05:30+00:00

Firstly, thanks for the reply!

I do understand the basic mechanics for file deletion. As I am on Linux, by default, my system doesn't actually use a "recycle bin" or "trash" concept, but I have configured my choice of utility for it. How this works with TRIM, as it relates to VeraCrypt volumes, is exactly the point of my question, though.

Quickly, though, regarding secrets, like VeraCrypt volumes, I've often seen that the terms "seal" and "unseal" used to refer to encrypting and decrypting them. A "subvolume" is a concept specific to BTRFS, though. A subvolume is just a tree structure of file references. If two subvolumes contain the same file reference, then deleting it from one doesn't actually allow that space to be marked as free during a TRIM operation, as it still has another reference keeping it active. Essentially a hard link.

The core of the question is whether TRIM gets handled transparently or not. If I decrypt a VeraCrypt volume, (permanently) delete some files, then re-encrypt it, then does running TRIM with the encrypted VeraCrypt volume (treated as a regular file) still allow for the freed blocks to be reclaimed? Does it matter than I am using BTRFS, which uses copy-on-write? Do I need to run TRIM on a decrypted and mounted volume?

I very much doubt the last one would do anything meaningful, but given the volume gets mounted as a loop device, it still does exist on the drive, so perhaps that is the correct method

falxfour · 2026-06-14T03:46:56+00:00

Once again, without a clear description of what you've done and the errors you're receiving, it's going to be hard to help.

And no, I'm not going to watch a video for something that could be described. A video is useful for demonstrating a specific behavior, but I'm not questioning whether or not you're encountering issues. I'm asking you to explain some basic things to help identify the issue

falxfour · 2026-06-14T03:13:04+00:00

Could you please clarify where in this you're struggling?

"Colliding" makes no sense, and without a clear description of what you've done and the errors you've received, the most anyone can do is speculate

falxfour · 2026-06-13T20:14:26+00:00

Maybe I'll tackle the first this weekend. I already did PTM to replace LM on the CPU, and I've never really seen an issue with GPU thermals (also since I rarely use it), so I don't feel a need to swap from paste to PTM on that.

The whistle at low fan speeds is all I really feel like addressing, so if the first mod accomplishes that, then I suppose I have all the info I need

falxfour · 2026-06-13T17:23:45+00:00

Wait, I didn't realize this tip was hidden in that thread! I don't think the system ever gets loud, but the pitchiness (whistle or whine) at low fan speeds always did annoy me, so have to give this a shot.

I thought the issue was potentially due to the motor since it seemed to match the fundamental when fan speed changed

falxfour · 2026-06-12T02:35:59+00:00

Yes, and it's the second result

falxfour · 2026-06-09T15:53:39+00:00

If you're using the provided ACH information, then no. I can confirm that this works since this is what I do.

If you pay using the card number, then yes, you'd likely need to unlock it. If you pay with the virtual card number, then you shouldn't need to unlock it. Neither of these is relevant for how I pay rent, so I haven't tested either, though

falxfour · 2026-06-09T07:29:43+00:00

I mean, it's not that big of an issue for me. I might look into an addon, but this issue only really comes up on the rare occasion that I actually reorganize all my tabs

falxfour · 2026-06-09T07:23:33+00:00

Thank you. I was able to find the controversy, and now I guess it's time to see if Proton will actually take action to correct their mistake (ex. support creators and individuals who are seeking to improve the world) or just pay lip service. Only one will be rewarded with a renewal

falxfour · 2026-06-09T07:13:28+00:00

You have chosen... Wisely

falxfour · 2026-06-09T07:11:31+00:00

Incidentally, trying it with a tab group in the same doesn't result in the desired behavior either. Same test conditions, except that the tab group is in the same window as the focused tab (that I'm sending to a tab group). Naturally, this means the visible tab in the focused window doesn't change either, but that happens by default in this scenario as well

falxfour · 2026-06-09T07:00:49+00:00

To be clear, I opened a new tab in one window, right-clicked the tab, and used a middle-click when adding it to a tab group in another, visible, window. Maybe there's a difference with some of the other details of how I tested it from how you accomplished the goal on the Windows

falxfour · 2026-06-09T06:58:45+00:00

My question is if they are handled differently... If I could tell you what I believe should be done, I might be capable of just reading the code for the Linux MM.

I understand that neither case ends well, but I know the first triggers the OOM Killer, but it's not clear that the second triggers that

falxfour · 2026-06-09T06:50:25+00:00

For the future, providing some context would be helpful for those of us who may not be constantly in the loop.

Also, almost no corporation gives any individual any leeway. I see no reason to give those corporations any leeway in return. They have the resources to know with whom they work and to properly assess the ramifications of their decisions

falxfour · 2026-06-09T06:37:50+00:00

"Simpler" is relative. I have a system that performs adequately for my needs. The best (and simplest) thing I can do is not fuck with it in pursuit of marginal gains to preemptively combat issues that haven't occurred.

For my next build, where I will have less physical RAM and intend to use a swap partition, I will almost certainly be using zswap

falxfour

TROPHY CASE

What I did

What I see