[gpfsug-discuss] Metadata only system pool

Alex Chekholko alex at calicolabs.com
Tue Jan 23 17:27:57 GMT 2018


2.8TB seems quite high for only 350M inodes.  Are you sure you only have
metadata in there?

On Tue, Jan 23, 2018 at 9:25 AM, Frederick Stock <stockf at us.ibm.com> wrote:

> One possibility is the creation/expansion of directories or allocation of
> indirect blocks for large files.
>
> Not sure if this is the issue here but at one time inode allocation was
> considered slow and so folks may have pre-allocated inodes to avoid that
> overhead during file creation.  To my understanding inode creation time is
> not so slow that users need to pre-allocate inodes.  Yes, there are likely
> some applications where pre-allocating may be necessary but I expect they
> would be the exception.  I mention this because you have a lot of free
> inodes and of course once they are allocated they cannot be de-allocated.
>
> Fred
> __________________________________________________
> Fred Stock | IBM Pittsburgh Lab | 720-430-8821 <(720)%20430-8821>
> stockf at us.ibm.com
>
>
>
> From:        "Buterbaugh, Kevin L" <Kevin.Buterbaugh at Vanderbilt.Edu>
> To:        gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
> Date:        01/23/2018 12:17 PM
> Subject:        [gpfsug-discuss] Metadata only system pool
> Sent by:        gpfsug-discuss-bounces at spectrumscale.org
> ------------------------------
>
>
>
> Hi All,
>
> I was under the (possibly false) impression that if you have a filesystem
> where the system pool contains metadata only then the only thing that would
> cause the amount of free space in that pool to change is the creation of
> more inodes … is that correct?  In other words, given that I have a
> filesystem with 130 million free (but allocated) inodes:
>
> Inode Information
> -----------------
> Number of used inodes:       218635454
> Number of free inodes:       131364674
> Number of allocated inodes:  350000128
> Maximum number of inodes:    350000128
>
> I would not expect that a user creating a few hundred or thousands of
> files could cause a “no space left on device” error (which I’ve got one
> user getting).  There’s plenty of free data space, BTW.
>
> Now my system pool is almost “full”:
>
> (pool total)           2.878T                                   34M (  0%)
>        140.9M ( 0%)
>
> But again, what - outside of me creating more inodes - would cause that to
> change??
>
> Thanks…
>
> Kevin
>
>> Kevin Buterbaugh - Senior System Administrator
> Vanderbilt University - Advanced Computing Center for Research and
> Education
> *Kevin.Buterbaugh at vanderbilt.edu* <Kevin.Buterbaugh at vanderbilt.edu>-
> (615)875-9633 <(615)%20875-9633>
>
>
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