#386 Creating large container on macOS is terribly slow

[PierU]

On macOS 10.12, latest Veracrypt version, creation of a 2TB container on an external disk plugged in USB3.

Until 40% completion everything looks OK, the container is filled at a 120-150MB/s rate, which is approximately the nominal throughput of this disk. CPU usage around 30%.

Then things tend to go wrong, with cyclic pauses of the process. Around 50% completion, the contained is filled during 20s, then nothing happens during 10s, then it is filled during 20s, etc... Around 80% completion, it rather cycles of 10s filling and 20s pause. I stopped the process at this point, it was slower and slower and would have take hours to complete...

I could reproduce the problem. On a forum, another user reported a similar issue when trying to create a 3TB container under macOS 10.15, and even worse : around 30% completion his machine was becoming unresponsive (until he stopped Veracrypt). He could also reproduce the problem.

Looks like there is an issue with large container (1TB or more) creation on macOS...

[Jakob]

Hello,

I can see the problem on the PC too.
From about 1 TB of continuous writing to a container, the combination of VeraCrypt and large container starts to slow down and fill up the Windows write cache, while the system actually only writes 1 ~ 4MB / s, the TaskManager shows something of 60 ~ 80MB / s write performance the hard disk drive.

Drive / container size = 10 TB
OS = Windows 8.1
VeraVersion = 1.24.7

Problem = on multiple systems and containers