LVM Thinpool Snapshots Broken In 6.5?

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Hi, I just installed a CentOS 6.5 System with the intention of using thinly provisioned snapshots. I created the volume group, a thinpool and then a logical volume. All of that works fine but when I create a snapshot
“mysnap” then the snapshot volume gets displayed in the “lvs” output with the correct information but apparently no device nodes are created under /dev/mapper/ or /dev/(volumge_group_name). Any ideas what might be going on here?

Regards,
Dennis

One thought on - LVM Thinpool Snapshots Broken In 6.5?

  • For the people who run into this as well:
    This is apparently a feature and not a bug. Thin provisioning snapshots are no longer automatically activated and a “skip activation” flag is set during creation by default. One has to add the “-K” option to
    “lvchange -ay ” to have lvchange ignore this flag and activate the volume for real. “-k” can be used on lvcreate to not add this flag to the volume. See man lvchange/lvcreate for more details.
    /etc/lvm/lvm.conf also contains a “auto_set_activation_skip” option now that controls this.

    Apparently this was changed in 6.5 but the changes were not mentioned in the release notes.

    Regards,
    Dennis