Topic
  • 2 replies
  • Latest Post - ‏2013-09-09T15:03:23Z by FCharlier
FCharlier
FCharlier
7 Posts

Pinned topic Free/Used/Allocated/Max inodes

‏2013-09-09T11:59:32Z |

Hi,

I would like to implement a small script for monitoring inode usage on gpfs filesystems. At this step, I don't clearly understand relations between free, used, allocated and maximum numbers of inodes.  Anybody help?

  • sdenham
    sdenham
    70 Posts

    Re: Free/Used/Allocated/Max inodes

    ‏2013-09-09T12:15:31Z  

    As I understand it (and I am not a developer).

    Free inodes are those available for immediate use.

    Used is the obvious number of inodes that contain live information.

    Allocated is the sum of Free + Used, and is the number of inodes that have been created in the file system.

    Maximum is the upper limit defined for the FS.  When free is exhausted, additional inodes will be created up to this maximum before a request will be denied. This allocation of inodes is not instantaneous and can cause FS slowdowns, so  you don't want it happening often. 

    Space between Allocated and Maximum is also available for other file system objects until allocated. Once space has been allocated as inodes, it is forever inodes. You can't, to the best of my knowledge, shrink the number of inodes if you overallocate them.  When you set the maximum number of inodes with mmcrfs/mmchfs, you can specify both Maximum and Allocated.

     

  • FCharlier
    FCharlier
    7 Posts

    Re: Free/Used/Allocated/Max inodes

    ‏2013-09-09T15:03:23Z  
    • sdenham
    • ‏2013-09-09T12:15:31Z

    As I understand it (and I am not a developer).

    Free inodes are those available for immediate use.

    Used is the obvious number of inodes that contain live information.

    Allocated is the sum of Free + Used, and is the number of inodes that have been created in the file system.

    Maximum is the upper limit defined for the FS.  When free is exhausted, additional inodes will be created up to this maximum before a request will be denied. This allocation of inodes is not instantaneous and can cause FS slowdowns, so  you don't want it happening often. 

    Space between Allocated and Maximum is also available for other file system objects until allocated. Once space has been allocated as inodes, it is forever inodes. You can't, to the best of my knowledge, shrink the number of inodes if you overallocate them.  When you set the maximum number of inodes with mmcrfs/mmchfs, you can specify both Maximum and Allocated.

     

    @sdenham: ok, thank you for your response.