Working from home during these Corona-days I'm short on resources.
- no Linux machine available
- limited disk space
So I decided to give Docker in Windows 10 (named Docker Desktop) a try. 
This worked nicely after some reboot (it's Windows !  sad )   and killing my VMware  sad to have Hyper-V . Next, I tried to implement  Durable %SYS
And this was rather disappointing. 
Independent of what IRIS container I used (released or preview or community edition) it crashed at start.
Using docker run -it  ...   (instead of -d) to see what's happening uncovered this strange error.
 
05/05/20-21:59:12:977 (364) 0 [Utility.Event] Executing rm -f /usr/irissys/bin/irisinstall
05/05/20-21:59:12:981 (364) 0 [Utility.Event] Executing rm -f /usr/irissys/bin/irisuxsinst
05/05/20-21:59:12:986 (364) 0 [Utility.Event] Executing rm -f /external/durable/CloneIncomplete
05/05/20-21:59:12:992 (364) 0 [Utility.Event] Instance IRIS data directory moved to /external/durable
05/05/20-21:59:12:993 (364) 0 [Utility.Event] Executing find /usr/irissys/ -type d -exec chmod ugo-w {} +
05/05/20-21:59:13:028 (364) 0 [Utility.Event] Executing chmod ugo-w /usr/irissys/

[ERROR] Possible causes:
[ERROR]  -
Incorrect user/group ownership of IRIS binaries
[ERROR]  - Insufficient write permissions to ISC_DATA_DIRECTORY
[FATAL] Error starting InterSystems IRIS
The reasons are the high lighted lines
ISC_DATA_DIRECTORY  had no protection at all and was not affected.
More detailed interactive tests showed a mismatch between file ownership and user in docker.

AS it happened with several IRIS containers I assume the problem in Desktop Docker and/or it'S underlying Windows 10.

As a workaround for me, I developed a customized lightweight durability solution that avoids this step. ​