Large VeraCrypt mount hangs occasionally

[olddragon]

Hi,

I'm looking for tips and hints on how to debug a VeraCrypt IO issue where the drive just hangs.

When fully encrypting external drives larger than 3 TB, the resulting mount often hangs on prolonged write sessions.

After writing to the drive for 15-20 minutes, IO stops for 10-20 seconds about every minute, then resumes as before.
While IO is operational, speed is good (100+ MB/s using 5400 RPM Silicon Power external drives) and no data corruption happens.
While IO pauses, the drive is unresponsible, trying to even list files just lefts programs like Total Commander or Windows Explorer hanging.

On rare occasions, IO just stops and can't be resumed without a reboot.

I never had this issue using smaller (1-2 TB) external drives, but am facing the problem with all my large (4-5 TB) drives.

I don't have any issue with the drives if they are not encypted with VeraCrypt.

VeraCrypt mounts are formatted as NTFS by VeraCrypt.

My config:

Edition Windows 10 Pro
Version 22H2
Installed on ‎2021. ‎03. ‎15.
OS build 19045.2251
Experience Windows Feature Experience Pack 120.2212.4180.0

Veracrypt: 1.25.9 (64 bit)

Thank you for any help, happy to provide more information if technical instructions are given on how to obtain it.

[RobL]

This seems to only be an issue for NTFS formatted drives. Reformatting with ExFAT, no such slowdown. I've personally experienced this as well. Wonder if this is somehow related to how the filesystem is mounted and the allocation table equivalent with NTFS?

[Nosy BumbleBee]

I have experienced the same. I have been using Veracrypt for many years and over the years I increased the size of my hard disks a lot, I'm using 18Tb drives right now. And I noticed that every time I increased the drive size, Veracrypt became slower and slower. Write speeds of only 20 - 50 Mbs were not unusual. And the sudden transfer stops for a second or two occurred as well. For me personally, this was not practical anymore and I had to use another encryption program. I hope this gets fixed in the future so I can use Veracrypt again, because I really like the program. I know that Mounir has addressed this in the past and explained that the slowdown was a result of how Veracrypt makes no difference if it writes to an encrypted volume or container. I hope I explained it correct, I'm no programmer :) Mounir said that it needs a complete rewrite of Veracrypt (make a version especially for container encryption and one for volume encryption) . And Mounir has a personal and professional life as well, so he is limited in his resources, I totally understand that. I made a few donations in the past and I hope more people will do this so Mounir can spend more time in Veracrypt.

[RobL]

Thanks for your reply. May I ask, what alternatives to Veracrypt are there? My sentiments about VeraCrypt, after TrueCrypt went into unsupported mode.
BTW, I have been able to achieve sustained 150-180MB/sec using ExFAT formatted 8TB HDD with 4k cluster size, no slowdown at all.

[Nosy BumbleBee]

If you're looking for a free, open source and audited encryption program, there isn't much choice. The only other one I know of is Diskcryptor. But this has not been audited as far as I know, and it's not maintained frequently.
Bitlocker is free (with Win Pro), but not open source and I don't trust Microsoft :)
I found this company from Finland called Jetico. They've been in the encryption business for 30 years and have a product called BestCrypt.
It's not free nor opensource, but I guess it's better than nothing. If Veracrypt ever becomes usable for me again, I will switch back to it in a heartbeat.
You said that you had good results with exFAT, but that's a file-system more suited for removable storage like flash memory. It has no journaling (useful against data corruption) and also no file permissions capability like NTFS has. But maybe that's something you are not interested in.
My encrypted drives do about 210MB/s sustained according to CrystalDiskMark.