Your "cron" job on mercury /root/bin/backup-nightly.sh | mailx -r [email protected] -s "mercury Nightly Backup Cron" [email protected] produced the following output: cannot destroy 'zpool1/nmpdr-homes@nightly': dataset is busy cannot create snapshot 'zpool1/nmpdr-homes@nightly': dataset already exists cannot destroy 'zpool1/proj-climate1@nightly': dataset is busy cannot create snapshot 'zpool1/proj-climate1@nightly': dataset already exists