Our initial Foglight Experience Monitor (FxM) backup was was 3.5 GB. We didn't make any major changes during the past year--so we're wondering how what is stored in our FTP backup directory would grow to 37 GB over time. At what point will the size of the backup stop growing? Should we be changing our FTP backup directory every so often?
If you change the FTP backup directory, the system will do a full backup to the new directory (FxM uses the list of files in the FTP directory to decide what needs to be backed up).
Otherwise, the system performs incremental backups of the new data. Even if you don't make any configuration changes over the year, FxM would continue to collect data. So, your FTP directory will continue to grow over time; the size of backup will continue to grow forever. That FTP directory would be holding more than what the FxM machine database would be able to hold at any given time. That is why it can be many times larger.
That is because if you'd performed regular backups and never cleared out the backup directory you'd have a years worth of full data. The FxM appliance is rolled off/drops old data sooner or later--depending on its time frame (larger time intervals are held longer than shorter). But all that data is still in the FTP backup directory.
That is why one of our recommended best practices is to routinely (1/month, 1/quarter, etc) backup everything in their FTP directory to tape (or whatever you normally use for long term storage). After the FTP directory is backed up to tape, clear the FTP directory. This keeps it from growing forever larger.
If you do not want to backup to tape, then just copy the contents of the backup directory to another directory every N weeks and then clear the original directory.