My general rule of thumb is to keep available disk space around 20% to 40%.
I am having discussion problems with IT techs (?) who have let primary drive space on small business servers drop below 5%. These businesses are having performance problems and I need their IT support to reallocate space from another partition to the primary drive if possible, or they need to increase the size of the primary drive hardware. However, these IT techs (?) are only willing to delete files to free up space. I suspect there are personal stumbling blocks in play, which are preventing these techs from tackling the job of reallocating space or migrating a primary drive to a new drive.
I am looking for a strong and highly credible reference I can send to these IT techs which states clearly what the % of free space should be and why. Does anyone have a reference for this? I would take a PDF file from a textbook training manual, a web link, etc. I would prefer this not be a blog, discussion, or open forum because that is personal opinion. I would prefer this be a highly credible professional referral source.