Oh, That's a thought! I didn't try such option. Will do it.
What I have now: I've created both /var/log/v2ray and /var/log.hdd/v2ray sub-directories.
As a result, both of them survive shrinking.
What is most interesting, V2ray starts to write to /var//log/v2ray, though '/var/log.hdd/v2ray" is set in the config, as the log directory. After few seconds (or tens of seconds) it stops to write lod there and starts to write to "log.hdd". I'm puzzled. But of course this is not your script problem, as I believe.
As for "journal" missing, please look at the screenshot attached. This is an obvious mistake. In fact we have a link instead of the real directory, and have nothing instead of link.
You see the "log.hdd" sub-directory. And once again, everything is OK in the partition before SD card insertion into the boot slot.
I.e. we have directory in the "log.hdd" and the link to it in the "log".
Also, I'd like to ask, if there is an option do not show all those fast scrolling lines during the process.