mongodb eat root filesystem space? how to solve it ?

[likuku]

mongodb running 3-4 days, root fs of free space is gradually reduced until 100% full (df -h show me that info) ..

/ etc / mongodb.conf Lane dbpath = / export / storage / mongodb (/ export mounted another filesystem)

when i use du -shc /* , root filesystem was only using 30% of the total.

After that, I restart/stop mongodb, the root filesystem df and du displays the results on the same.

How to solve this situation?

Thanks~

# Operating Environment Information:

debian linux 6.0 x86_64 xen domU

Linux monitor-test 3.2.0-4-amd64 #1 SMP Debian 3.2.35-2 x86_64 GNU/Linux

filesystem type : EXT4

debian linux 6.0 x86_64 xen dom0

Dell R620

[likuku]

add info of mongodb version:

mongodb-10gen  2.4.8 (apt-get from 10gen offical source)

在 2014年1月8日星期三UTC+8上午11时26分59秒，likuku写道：

[Sam Millman]

What kind of queries are you throwing at MongoDB? It sounds like you are suffering from excessive document movement if you are expecting there to still be free space.

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[Eoin Brazil]

Hi,

It is difficult to determine what exactly is the root cause of this behaviour without some additional details. However it might be helpful to explain the MongoDB storage layer which preallocates data file in advance to prevent file system fragmentation. It will aggressive preallocate the next file to be filled for each database (initially 64MB, the next file will be 128MB and so on up until 2GB where all subsequent file allocations will be done at 2GB). This is covered in the documentation (http://docs.mongodb.org/manual/faq/storage/#why-are-the-files-in-my-data-directory-larger-than-the-data-in-my-database) and in a recent presentation (http://www.mongodb.com/presentations/understanding-mongodb-storage-performance-and-data-safety).

What operations are you performing on the database ? Can you provide some details and examples ?

The growth over 3 days of operation may be completely normal behaviour due to the preallocation approach used by MongoDB. If you can provide more details then we can better understand what is occurring and provide better answers.

Best regards,

Eoin

[Asya Kamsky]

I'm afraid you will need to show output of your df commands, etc. because it sounds to me like you are saying:

MongoDB data directories are in /export/storage/mongodb and that your / root partition which is a separate device from /export/storage got filled up by MongoDB?

That sounds somewhat unusual - in fact, MongoDB does not write data anywhere except inside of its dbpath so it sounds somewhat implausible!   

Are you sure this had something to do with MongoDB?   When you ran du on your root partition, what did you see taking up space?   What about the /export/storage partition - did it show growth while MongoDB was running?

Is it possible that you started mongod without using the mongodb.conf and there was a directory in /data/db that it put its files in?

Asya

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[Asya Kamsky]

I just want to point out that while what Eoin says is 100% correct, all of the files he is referring to would be in the same directory and that is the "dbpath" of mongod process which you says in the first post is a separate device from the one that became full.

Asya