MongoDB cluster refactoring, freeing up disk space

MongoDB cluster refactoring, freeing up disk space

Because MongoDB does not reclaim the corresponding disk space after deleting some of the data, it frees up disk space by rebuilding the data directory. an experimental environment

A replica set is configured, which consists of the following three nodes:

10.192.203.201:27017 PRIMARY

10.192.203.202:27017 Secondary

10.192.203.202:10001 Arbiter Two experimental steps
2.1 Simulation Environment

Use DBA;
for (Var i=0;i<1000000;i++) Db.c.insert ({uid:i,uname: ' Osqlfan ' +i});
Db.c.find (). Count (); #1000000
 db.stats ();
{
	"db": "DBA",
	"collections": 5,
	"Objects": 1000111,
	"avgobjsize": 111.9994880568257,
	" DataSize ": 112011920,
	" storagesize ": 174796800,
	" numextents ": +,
	" Indexes ": 3,
	" Indexsize ": 32475072,
	"fileSize": 469762048,
	"nssizemb": +,
	"Extentfreelist": {
		"num": 0,
		"totalsize ": 0
	},
	" Datafileversion ": {
		" Major ": 4,
		" minor ": $
	},
	" OK ": 1
}

Disk space increased by 400M data:

-RW-------. 1 root root 134217728 Nov 7 13:38 dba.1

-RW-------. 1 root root 268435456 Nov 7 13:38 dba.2

[Root@slave2 ~]# Du-sh/data/mongo/data

4.7g/data/mongo/data

 

#删除dba. C Table Data:
myreplset:primary> db.c.drop ();
True
myreplset:primary> Db.c.find (). Count ();
0
myreplset:primary> db.stats ();
{
"db": "DBA",
"Collections": 4,
"Objects": 108,
"avgobjsize": 108.44444444444444,
"datasize ": 11712,
" storagesize ": 61440,
" numextents ": 5,
" Indexes ": 2,
" indexsize ": 16352,
" FileSize ": 469762048,
" nssizemb ": +,
" Extentfreelist ": {
" num ":"
totalsize ": 212492288
  },
"Datafileversion": {
"Major": 4,
"minor": $
},
"OK": 1
}

See datasize,indexsize,storagesize are smaller, but filesize unchanged, and MONGO data directory still occupy 4.7G.

2.2 Make sure to refactor from library 10.192.203.202:27017 first

#查看主从关系

Myreplset:primary>rs.status ();
                    {"Set": "Myreplset", "date": Isodate ("2016-11-07t07:10:50.717z"), "MyState": 1, "members": [{
                    "_id": 0, "name": "10.192.203.201:27017", "Health": 1, "State": 1, "Statestr": "PRIMARY", "uptime": 964, "optime ": Timestamp (1478239977, 594)," Optimedate ": Isodate (" 2016-11-04t06:12:57z ")," ele
                    Ctiontime ": Timestamp (1478502021, 1)," Electiondate ": Isodate (" 2016-11-07t07:00:21z "),
                    "ConfigVersion": 2, "Self": true}, {"_id": 1,
                    "Name": "10.192.203.202:27017", "Health": 1, "state": 2, "Statestr": "Secondary", "uptime": 628, "optime": Timestamp(1478239977, 594), "Optimedate": Isodate ("2016-11-04t06:12:57z"), "Lastheartbeat"
                    : Isodate ("2016-11-07t07:10:49.257z"), "Lastheartbeatrecv": Isodate ("2016-11-07t07:10:50.143z"), "Pingms": 2, "ConfigVersion": 2}, {"_id":
                    2, "name": "10.192.203.202:10001", "Health": 1, "state": 7, "Statestr": "Arbiter", "uptime": 618, "Lastheartbeat": Isodate (
                    "2016-11-07t07:10:49.416z"), "Lastheartbeatrecv": Isodate ("2016-11-07t07:10:49.847z"), "Pingms": 2, "ConfigVersion": 2}], "OK": 1}

2.2.1 Shutting down the database

myreplset:secondary> use admin;
Switched to DB admin
myreplset:secondary> db.shutdownserver ();
2016-11-07t15:14:42.548+0800 I NETWORK  dbclientcursor::init call () failed
server should is down ...
2016-11-07t15:14:42.571+0800 I NETWORK  trying reconnect to 127.0.0.1:27017 (127.0.0.1) failed
2016-11-07t15 : 14:42.575+0800 W NETWORK  Failed to connect to 127.0.0.1:27017, reason:errno:111 Connection refused
2016-11-07t15:14:42.575+0800 I NETWORK  reconnect 127.0.0.1:27017 (127.0.0.1) failedfailed couldn ' t connect to Server 127.0.0.1:27017 (127.0.0.1), Connectionattempt failed
2016-11-07t15:14:42.634+0800 I NETWORK  trying Reconnect to 127.0.0.1:27017 (127.0.0.1) failed
2016-11-07t15:14:42.637+0800 W NETWORK  failed-Connect to 127.0.0.1:27017, reason:errno:111 Connection refused
2016-11-07t15:14:42.638+0800i NETWORK  Reconnect 127.0.0.1:27017 (127.0.0.1) failed failed couldn ' t connect to server 127.0.0.1:27017 (127.0.0.1), connection attempt Failed

2.2.2 Backup, delete, rebuild data directory

Back up the 10.192.203.202:27017 data directory, omitted here

After the backup is complete, delete and rebuild the directory.

Rm-rf/data/mongo/data

Mkdir/data/mongo/data 2.2.3 Startup Database

To start the 10.192.203.202:27017 process:

/USR/LOCAL/MONGODB/BIN/MONGOD--CONFIG/USR/LOCAL/MONGODB/MONGOD.CNF--replset myreplset-rest 2.2.4 Check

Check that the database is healthy and that the previous database exists.

Check that the disk space is down.

After inspection, the space shrinks to 4.3G and shrinks by 400MB.

2.3 Refactoring the main library
2.3.1 Switching master-Slave relations

Since 201 is the master, it is necessary to switch the master-slave relationship between 201 and 202:27,017. In addition to the quorum node, this experiment has only one slave node. If there is more than one node, the remaining slave nodes must be

Execution: Rs.freeze (300); (lock from, so that it does not turn into the main library)

In 10.192.203.201:27017 execution: Rs.stepdown (30); (Downgrade it)

--freeze () and Stepdown units are all seconds.

Rs.status () to see if the master-slave relationship is switched. 2.3.2 shutting down the database

To stop the 10.192.203.201:27017 process:

Myreplset:secondary>use admin;

Switched to DB admin

Myreplset:secondary> Db.shutdownserver (); 2.3.3 Backup Delete, rebuild its data directory

Backup slightly.

Rm-rf/data/mongo/data

Mkdir/data/mongo/data 2.3.4 Startup Database

To start the 10.192.203.201:27017 process:

/USR/LOCAL/MONGODB/BIN/MONGOD--CONFIG/USR/LOCAL/MONGODB/MONGOD.CNF--replset myreplset-rest 2.3.4 Check

Check that the database is healthy and that the previous database exists.

Check that the disk space is down.

After inspection, the space shrinks to 4.3G and shrinks by 400MB.

--The quorum node does not need to be refactored.

After the refactoring is complete, you can switch back to the original master-slave state.