执行df -h
none 13G 12G 739M 95% /var/lib/docker/aufs/mnt/2a6e09b9116bcf0a50566f8690b9b8c33ce30422ad904e0dc02c2d20916f13e5
shm 64M 0 64M 0% /var/lib/docker/containers/47d901863eb44622ef4cd8846d570a1aa7e3ae132642e45e1370ff8fb08b547d/shm
none 13G 12G 739M 95% /var/lib/docker/aufs/mnt/90b708a0433f3ed54d88445fdf9113ac66c2643d75af0e2f56d09003d15910bf
shm 64M 0 64M 0% /var/lib/docker/containers/66021c17764054023c1533064049a72e72c085c8304d8a4b847cda5f04401548/shm
none 13G 12G 739M 95% /var/lib/docker/aufs/mnt/bfe08f3013d8221bd2a5d6f88d26783686511b6735dd436b72eb6a50d2dc027e
shm 64M 0 64M 0% /var/lib/docker/containers/a3ab7d7556fa695c86a62eb436620a5b002c5ff9c0a9d46fe2e94ee3a4797745/shm
none 13G 12G 739M 95% /var/lib/docker/aufs/mnt/f926cef5951ff7812c51d4230e4bca3570ea09fcdd349cccb255f1e0a2f2293b
shm 64M 0 64M 0% /var/lib/docker/containers/f34775e4bac4720971793522419c2e6f2814f42042d0873514548f8161f9b431/shm
none 13G 12G 739M 95% /var/lib/docker/aufs/mnt/ddbd83ecd99ccd36c3568e1aa9355d0fb72ce545561bb9e3d02fe3e55a73eef0
shm 64M 0 64M 0% /var/lib/docker/containers/bd60d19dd6aae7164dd9dd2d32f75f326ba2909d8a7787153fb1c2856bfea73f/shm
none 13G 12G 739M 95% /var/lib/docker/aufs/mnt/595478be2d862b9a0b17564a873e2795f95265c48e8e64a6fb238325db0b3a8e
shm 64M 0 64M 0% /var/lib/docker/containers/f0171ad04d32d51ebff00778a8a7b71976abaa8ddb8c0130fff88c08718ed90c/shm
虚机空间没这么多呀！怎么回事？