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2 replies Latest Post - ‏2012-10-16T19:05:59Z by SystemAdmin
2092 Posts

Pinned topic GPFS V3.5 Fileset snapshots

‏2012-10-15T23:31:21Z |
Hi all,

When I try to create snapshots of GPFS filesets, I get an error:

  1. mmcrsnapshot gpfs0 software-monday -j software
Cannot create new snapshot: fileset software does not support fileset snapshots.
Invalid argument
mmcrsnapshot: tscrsnapshot failed. Error code 22.
mmcrsnapshot: Command failed. Examine previous error messages to determine cause.

  1. mmlsfileset gpfs0 software -L
Filesets in file system 'mira-fs0':
Name Id RootInode ParentId Created InodeSpace MaxInodes AllocInodes Comment
software 1 223148809 0 Mon Oct 15 23:28:54 2012 0 0 0
The filesystem was created as the newest version, and we're running GPFS on our NSD servers:

  1. rpm -qa | grep gpfs.base
]# mmlsfs gpfs0 -V
flag value description

-V 13.01 ( File system version

I've read through the manpage, as well as looked at the GPFS v3.5 Advanced Admin Guide that references fileset level snapshots. I didn't see anything jump out at me to indicate that I didn't RTFM (fine), however there is always a 60% chance that I'm 75% wrong.

Am I doing something wrong here?
Updated on 2012-10-16T19:05:59Z at 2012-10-16T19:05:59Z by SystemAdmin
  • SystemAdmin
    2092 Posts

    Re: GPFS V3.5 Fileset snapshots

    ‏2012-10-16T00:53:47Z  in response to SystemAdmin
    You need to specify "-inode-space new ..." on the mmcrfileset command.
    There are now two flavors of filesets, "original (now known as dependent)" and "independent".
    The files within an Independent fileset are all created within the same "inode space", facilitating snapshot operations...
    No doubt the doc could be improved... But read it over a few times, try the commands and see if it makes some sense!

    -inode-space {new | ExistingFileset}
    Specifies the type of fileset to create, which controls how inodes are allocated:
    Creates an independent fileset and its own dedicated inode space.
    Creates a dependent fileset that will share inode space with the specified ExistingFileset. The
    ExistingFileset can be root or any other independent fileset.
    If --inode-space is not specified, a dependent fileset will be created in the root inode space.
    • SystemAdmin
      2092 Posts

      Re: GPFS V3.5 Fileset snapshots

      ‏2012-10-16T19:05:59Z  in response to SystemAdmin
      Hi marc,

      Makes perfect sense, and obviously it worked fine after creating an independent fileset. Obviously I was 100% right about missing the independent inode space part in the admin guide. It would be helpful if the manpage for mmcrsnapshot had a note about that as well, since those admin guides change between every release, and sometimes I miss the new sections; my fault though.

      I've been a bit spoiled by ZFS's automagic snapshotting on filesystems, but conceptually they probably are implemented in a similar matter.

      Thanks for the help.