In UCCX 7 we have an inbuilt tool to take backup and hence specifically we dont install BARS on it.
Regarding the disc space for TAR files it depends upon the size of database.
If you have enabled the automatic recording feature then the tar file will keep growing depending upon the size of C:\Program Files\Cisco\Desktop_Audio folder on UCCX.
So whatever space you allocate you need to monitor it to avoid the out of disk space issues.
If you are not using automatic recording then you can take a backup and check the size of the tar file lets say its 2 gig.
Now in backup tool you can run schedule backup and there you set the preserve tar file option lets say you set it to preserve last 3 tar files then the system will overwrite the fourth backup file and you need max of 6 gig space(ideally)
But again i say the size depends on the size of the database and you need to monitor the disk space.
I have given you a small logic above using which you can allocate the disk space.
These are the paths to get to each CCX logs through CLI. They may be helpful if you are having issues accessing RTMT or downloading logs through it.
If you want to download them you have to prefix "file get " and you can add one of the options (re...