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Description of problem: Need to determine how to reclaim storage space to disk after deleting large number of records in the meter database. The meter database did contain ~400GB of data. We deleted the records by time stamp to the last 15 days so now it contains about 60GB. Now we need to figure out how to reclaim the space to disk. This is a 3 node cluster in an openstack environment.. Version-Release number of selected component (if applicable): [heat-admin@tpacpucctrl1 ~]$ rpm -qa | grep mongo mongodb-server-2.6.9-1.el7ost.x86_64 python-pymongo-2.5.2-2.el7ost.x86_64 mongodb-2.6.9-1.el7ost.x86_64 Additional Info: tripleo:PRIMARY> db.stats() { "db" : "ceilometer", "collections" : 7, "objects" : 36097501, "avgObjSize" : 1693.7871190584633, "dataSize" : 61141482224, "storageSize" : 346381305376, "numExtents" : 197, "indexes" : 11, "indexSize" : 23036738480, "fileSize" : 485028265984, "nsSizeMB" : 16, "dataFileVersion" : { "major" : 4, "minor" : 5 }, "extentFreeList" : { "num" : 0, "totalSize" : 0 }, "ok" : 1 } [root@tpacpucctrl2 ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/sda2 556G 523G 34G 94% / devtmpfs 63G 0 63G 0% /dev tmpfs 63G 39M 63G 1% /dev/shm tmpfs 63G 1.4M 63G 1% /run tmpfs 63G 0 63G 0% /sys/fs/cgroup tmpfs 13G 0 13G 0% /run/user/994 tmpfs 13G 0 13G 0% /run/user/993 tmpfs 13G 0 13G 0% /run/user/1000 tmpfs 13G 0 13G 0% /run/user/166 [root@tpacpucctrl2 ~]# du -ch /var/lib/mongodb/ 1.5G /var/lib/mongodb/journal 0 /var/lib/mongodb/_tmp 482G /var/lib/mongodb/ 482G total
As mentioned on IRC, using `compact` on newer versions or `repairDatabase` on older ones is probably the best way to do so when the data needs to be preserved. Otherwise, in cases where data can be deleted, then dropping the database should be enough to claim the allocated space back.
Dropped the DB by the following steps: 1.pcs resource disable openstack-ceilometer* 2.log into mongo and do db.dropDatabase() 3.check that /var/lib/mongodb/ceilometer* is gone. 4.may have to restart mongodb by doing pcs resource disable mongod-clone and re-enable 5.do use ceilometer; then db.stats() to ensure data is gone. 6. pcs resource enable openstack-ceilometer* 7. now you will see that the tables are back and meters begin to fill the database once again. 8. ll -h /var/lib/mongodb to see the new ceilometer db created Now the environment is stable with only 12% / use instad of 95%.