Customise oplogSize on Windows Server System

Tom Vo

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Jul 24, 2012, 5:37:26 AM7/24/12

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Dear all

I setup mongodb system on windows server with configure below:

Mongodb : version 2.0.6 64 bit
Operator System: Windows Server Standard 2008
Apply Replication Set on two servers:
RAM memory : 16 GB

HDD : 500 GB

And I set oplogSize parameter is 8192. I use mongotop tool to monitor mongodb instance as below. As mentioned on http://docs.mongodb.org/manual/core/replication/#replica-set-oplog-sizing, I don't config oplogSize on Windows Server System. Please help me more advice.

//////////////////// Replication operation log

ns total read write 2012-07-24T07:33:17
local.oplog.rs 2059ms 2059ms 0ms
local.system.replset 0ms 0ms 0ms
local.system.namespaces 0ms 0ms 0ms
local.system.indexes 0ms 0ms 0ms
local.replset.minvalid.$_id_ 0ms 0ms 0ms
local.replset.minvalid 0ms 0ms 0ms
local.me.$_id_ 0ms 0ms 0ms
local.me 0ms 0ms 0ms
admin.system.users.$_id_ 0ms 0ms 0ms

ns total read write 2012-07-24T07:33:18
local.oplog.rs 2090ms 2090ms 0ms
local.system.replset 0ms 0ms 0ms
local.system.namespaces 0ms 0ms 0ms
local.system.indexes 0ms 0ms 0ms
local.replset.minvalid.$_id_ 0ms 0ms 0ms
local.replset.minvalid 0ms 0ms 0ms
local.me.$_id_ 0ms 0ms 0ms
local.me 0ms 0ms 0ms
admin.system.users.$_id_ 0ms 0ms 0ms

ns total read write 2012-07-24T07:33:19
local.oplog.rs 2059ms 2059ms 0ms
local.system.replset 0ms 0ms 0ms
local.system.namespaces 0ms 0ms 0ms
local.system.indexes 0ms 0ms 0ms
local.replset.minvalid.$_id_ 0ms 0ms 0ms
local.replset.minvalid 0ms 0ms 0ms
local.me.$_id_ 0ms 0ms 0ms
local.me 0ms 0ms 0ms
admin.system.users.$_id_ 0ms 0ms 0ms

Thanks and Best Regards

Scott Hernandez

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Jul 24, 2012, 8:47:23 AM7/24/12

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Can you run this from the mongo javascript shell?
db.getSiblingDB("local").oplog.rs.stats()
db.printReplicationInfo()
rs.status()

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Tom Vo

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Jul 24, 2012, 8:57:00 PM7/24/12

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Dear Scott

Thanks for your support. Please refer list output of your guide:

G:\mongodb\bin\agency>mongo.exe admin --port 27031

MongoDB shell version: 2.0.6

connecting to: 127.0.0.1:27031/admin

> db.auth("admin","xxxxxxxxxxx")

1

PRIMARY> show dbs

STRUCT 0.078125GB

REMPL 4.076171875GB

TULFT 0.078125GB

admin 0.078125GB

local 8.07421875GB

PRIMARY> use local

switched to db local

PRIMARY> db.getSiblingDB("local").oplog.rs.stats()

{

"ns" : "local.oplog.rs",

"count" : 67866,

"size" : 70715292,

"avgObjSize" : 1041.9840862876845,

"storageSize" : 8589938624,

"numExtents" : 5,

"nindexes" : 0,

"lastExtentSize" : 4231168,

"paddingFactor" : 1,

"flags" : 0,

"totalIndexSize" : 0,

"indexSizes" : {

},

"capped" : 1,

"max" : 2147483647,

"ok" : 1

}

PRIMARY> db.printReplicationInfo()

configured oplog size: 8192MB

log length start to end: 670313secs (186.2hrs)

oplog first event time: Tue Jul 17 2012 02:39:28 GMT-0400 (SA Western Standard Time)

oplog last event time: Tue Jul 24 2012 20:51:21 GMT-0400 (SA Western Standard Time)

now: Tue Jul 24 2012 20:51:32 GMT-0400 (SA Western Standard Time)

PRIMARY> rs.status()

{

"set" : "REL_SET",

"date" : ISODate("2012-07-25T00:51:36Z"),

"myState" : 1,

"members" : [

{

"_id" : 0,

"name" : "SERVR01:27031",

"health" : 1,

"state" : 2,

"stateStr" : "SECONDARY",

"uptime" : 413440,

"optime" : {

"t" : 1343177494000,

"i" : 2

},

"optimeDate" : ISODate("2012-07-25T00:51:34Z"),

"lastHeartbeat" : ISODate("2012-07-25T00:51:34Z"),

"pingMs" : 0

},

{

"_id" : 1,

"name" : "SERVR02:27032",

"health" : 1,

"state" : 2,

"stateStr" : "SECONDARY",

"uptime" : 74290,

"optime" : {

"t" : 1343177494000,

"i" : 2

},

"optimeDate" : ISODate("2012-07-25T00:51:34Z"),

"lastHeartbeat" : ISODate("2012-07-25T00:51:34Z"),

"pingMs" : 0

},

{

"_id" : 2,

"name" : "SERVR02:27030",

"health" : 1,

"state" : 7,

"stateStr" : "ARBITER",

"uptime" : 413442,

"optime" : {

"t" : 0,

"i" : 0

},

"optimeDate" : ISODate("1970-01-01T00:00:00Z"),

"lastHeartbeat" : ISODate("2012-07-25T00:51:34Z"),

"pingMs" : 0

},

{

"_id" : 3,

"name" : "SERVR03:27031",

"health" : 1,

"state" : 1,

"stateStr" : "PRIMARY",

"optime" : {

"t" : 1343177494000,

"i" : 2

},

"optimeDate" : ISODate("2012-07-25T00:51:34Z"),

"self" : true

}

],

"ok" : 1

}

PRIMARY>

--

Thanks and Best Regards
-------------------------------------------------------------------------------------------------------------
Vo Tan Hau (TOM)
Senior Database Administrator
NEXCEL SOLUTIONS LTD
SMS Tower,Lot 40, Quang Trung Software City, District 12, HCMC, Vietnam.
Tel:+84-8-37154278 - Fax:+84-8-37154279 www.nexcel.vn
Messenger (Skype+Yahoo+Live): Vohau2002

Tom Vo

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Jul 25, 2012, 12:05:51 AM7/25/12

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FYI

Scott Hernandez

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Jul 25, 2012, 9:13:44 AM7/25/12

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Your oplog size looks fine and is what you have described. Is there a
problem or issue you are concerned about?

Tom Vo

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Jul 25, 2012, 9:47:25 PM7/25/12

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I don't know the best set oplog size on Windows Server System.

Could you guide me how to setup it because we have plan setup Mongodb base on Windows Server?

Scott Hernandez

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Jul 25, 2012, 10:04:38 PM7/25/12

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The oplog size is going to depend on how much data you change and how
often. It is very application dependent.

In the commands you posted you have an oplog which is 186hrs, or about
8days, so that is probably fine as long as that data is based on your
normal write patterns. You basically want an oplog which is many times
your largest time to recovery on failure or maintenance window.

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