journal data from previous devstack runs have been saved.

[Sam Wan]

If journal logs are large enough and not cleaned before current devstack runs, journal data from previous devstack is saved. This is a waste of both time and storage space and confusing for troubleshooting.

example:
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http://publiclogs.emc.com/vnx_ostack/EMC_VNX_iSCSI/1277/logs/screen-c-vol.txt.gz
http://publiclogs.emc.com/vnx_ostack/EMC_VNX_iSCSI/1278/logs/screen-c-vol.txt.gz
http://publiclogs.emc.com/vnx_ostack/EMC_VNX_iSCSI/1279/logs/screen-c-vol.txt.gz
http://publiclogs.emc.com/vnx_ostack/EMC_VNX_iSCSI/1280/logs/screen-c-vol.txt.gz
http://publiclogs.emc.com/vnx_ostack/EMC_VNX_iSCSI/1281/logs/screen-c-vol.txt.gz
http://publiclogs.emc.com/vnx_ostack/EMC_VNX_iSCSI/1282/logs/screen-c-vol.txt.gz
http://publiclogs.emc.com/vnx_ostack/EMC_VNX_iSCSI/1283/logs/screen-c-vol.txt.gz
-----

Later cinder-volume logs contain logs from previous ones.
------
sam@vnxvm1:/home/jenkins/workspace/EMC_VNX_iSCSI> zgrep 'devstack@c-vol' 1277/logs/screen-c-vol.txt.gz
Jul 11 00:45:15.093641 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 02:23:52.084738 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 02:50:22.609657 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
sam@vnxvm1:/home/jenkins/workspace/EMC_VNX_iSCSI> zgrep 'devstack@c-vol' 1278/logs/screen-c-vol.txt.gz
Jul 11 00:45:15.093641 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 02:23:52.084738 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 02:50:22.609657 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 05:04:13.141720 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 05:30:00.449629 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
sam@vnxvm1:/home/jenkins/workspace/EMC_VNX_iSCSI> zgrep 'devstack@c-vol' 1279/logs/screen-c-vol.txt.gz
Jul 11 00:45:15.093641 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 02:23:52.084738 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 02:50:22.609657 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 05:04:13.141720 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 05:30:00.449629 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 07:21:57.106428 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 07:47:21.017658 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
sam@vnxvm1:/home/jenkins/workspace/EMC_VNX_iSCSI> zgrep 'devstack@c-vol' 1280/logs/screen-c-vol.txt.gz
Jul 11 00:45:15.093641 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 02:23:52.084738 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 02:50:22.609657 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 05:04:13.141720 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 05:30:00.449629 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 07:21:57.106428 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 07:47:21.017658 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 09:24:06.607686 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 09:52:07.377667 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
sam@vnxvm1:/home/jenkins/workspace/EMC_VNX_iSCSI> zgrep 'devstack@c-vol' 1281/logs/screen-c-vol.txt.gz
Jul 11 00:45:15.093641 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 02:23:52.084738 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 02:50:22.609657 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 05:04:13.141720 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 05:30:00.449629 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 07:21:57.106428 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 07:47:21.017658 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 09:24:06.607686 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 09:52:07.377667 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 11:42:30.048846 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 12:11:17.093635 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
sam@vnxvm1:/home/jenkins/workspace/EMC_VNX_iSCSI> zgrep 'devstack@c-vol' 1282/logs/screen-c-vol.txt.gz
Jul 11 00:45:15.093641 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 02:23:52.084738 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 02:50:22.609657 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 05:04:13.141720 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 05:30:00.449629 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 07:21:57.106428 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 07:47:21.017658 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 09:24:06.607686 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 09:52:07.377667 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 11:42:30.048846 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 12:11:17.093635 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 13:55:25.703345 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 14:22:15.125640 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
sam@vnxvm1:/home/jenkins/workspace/EMC_VNX_iSCSI> zgrep 'devstack@c-vol' 1283/logs/screen-c-vol.txt.gz
Jul 11 00:45:15.093641 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 02:23:52.084738 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 02:50:22.609657 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 05:04:13.141720 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 05:30:00.449629 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 07:21:57.106428 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 07:47:21.017658 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 09:24:06.607686 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 09:52:07.377667 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 11:42:30.048846 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 12:11:17.093635 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 13:55:25.703345 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 14:22:15.125640 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
Jul 11 16:10:33.064740 vnxvm1 systemd[1]: Stopped Devstack <email address hidden>.
Jul 11 16:41:45.913619 vnxvm1 systemd[1]: Started Devstack <email address hidden>.
------

[Sam Wan (sam-wan)]

submit a patch for this issue: https://review.openstack.org/483165