[Gluster-users] how to downgrade GlusterFS from version 7 to 3.13?

[Riccardo Murri]

Hello,

Is there any way to downgrade a GlusterFS cluster?  Given the
performance issues that I have seen with GlusterFS 6 and 7 (reported
elsewhere on this mailing-list), I am now considering downgrading back
to GlusterFS 3.13.

I have set up a test cluster, copied some files on it, and tried to
downgrade the naive way (uninstall GlusterFS 7, install GlusterFS
3.13, do not touch bricks or other config).  This didn't work:
`glusterd` v3.13 complains that the o-version 70000 cannot be
restored.

So I tried again, this time trying to lower op-version before
downgrading the system packages, but `gluster set all op-version`
won't let me:

```
$ sudo gluster volume set all cluster.op-version 31000
volume set: failed: Required op-version (31000) should not be equal or
lower than current cluster op-version (70000).
```

What can I try next?

Thanks,
Riccardo