I'm not DX expert, but can't you apply classing rotating via crontab (and later use dx_read_log to read one of your interest)?

UNIX OS uses syslogd for logs. Each time the file is rotated by a crojob scheduled script, the script should include a restart of syslogd so that it starts writing to a clean file. Unfortunately, DX doesn't use syslog, it seems that logging is based on internal functions within the product.

OK, but does it have lock on inode too? Meaning, if you rotate it manually, does it follow rotated log or it starts writing to a new one? If it does follow rotated one then I see a problem and I suspect unless there is some kind of log management then only way to send HUP is to restart DX (which is something undesirable). If you don't get response by someone else I would suggest to open this with your support - in worst case this could be new RFE.