TerraMaster Official Forum

One key application I am considering for TNAS purchase is backup of a surveillance camera server. This server has 27 cameras and the software creates 27 folders, one for each camera. It then has subfolders in each of those for each calendar day. The video files are stored as event files in each calendar day folder. The server uses four 4TB drives and I was hoping to create a backup of the data in those drives but wanted to keep more of the older event files that the server software would delete as it runs out of drive space. For example I might allocate double the storage on the NAS to retain twice as much of the historical files. Is a standard backup app like TerraSync capable of this configuration?

I believe what I am hoping to achieve is called a mirror backup without removal of deleted files in source. i.e. do not remove deleted files back backup destination. The backup with retain as many of these historical files until drive space runs out and then the oldest will be discarded.

Please let me know if this is possible and share any related instructions on setup.

Are you planning to backup from Windows to TNAS?
You can use TerraSync to achieve one-way upload (with the option to delete the source directory without synchronizing).
However, due to TerraSync's feature of backing up based on file versions, the actual required space may be double, so it may not meet your needs.
You can consider mapping TNAS's disk to your PC and using other backup/synchronization tools such as TPC Backupper to achieve incremental backup (incremental backup does not synchronize or backup the "delete operation" of the source directory).

to be more clear, I want to mirror everything on the source, but also not to delete on the TNAS until TNAS runs out of space.

Generally speaking, Mirror mode refers to changing the destination directory to be consistent with the source directory. When the source directory deletes files, the destination directory will also delete files. If you need to use backup software to achieve your goals, choose Incremental instead of Mirror.
Generally speaking, synchronization software tools have the same effect as Mirror.

After initial research of backup software options, I have found a solution with Backupper using their Basic Sync mode along with the option to NOT sync the deletions. Now I need to solve the challange to clean up destination drive space on the NAS once it gets close to full. Is there a software based app to accomplish this by deleting the oldest files automatically? If not I have read about folks writing custom scripts to auto-delete old files for space.

Any tips are appreciated.

There is currently no relevant software in TOS that can achieve this.

Finding and deleting files that are "more than" so many days old is relatively simple; as is deleting the resultant empty folders - I use 'find' commands in scheduled tasks.
Finding and deleting "the oldest" may not be as easy as you would have to determine the "oldest" files. This may be complicated if you are copying files from another source into the nas. This is because the "date" the file is put on the nas will not be the same as the date it was created originally. (Linux tends to use "modification" date and many linux systems don't understand "creation" dates.) Unless, of course, the file names contain some form of date structure in which case you can 'find' on the basis of the filenames.

[I use my nas as an ftp repository for ip camera images, rather than as backup for the dvr/nvr which handles the overall video.]

I have experienced the creation/modification date conundrum when backing up the ftp images to second nas. I use a third party backup programme that does allow more control over what is kept and what is deleted but it does mean having to use a desktop to run it.