You may want to post your question to the dedicated DL Series subforum where people more knowledgeable about the DL 2100 may be able to assist. This subforum (My Cloud) is generally for the single bay/single drive My Cloud units.
https://community.wd.com/c/network-attached-storage/my-cloud-business-series
Having said that, use the forum search feature, magnifying glass icon upper right, and do a search for CRON. There are a number of discussions on using CRON to modify or include startup actions on the v2.x version firmware My Cloud units.
The following post in another subforum discusses how to make persistent system changes using crontab:
