Spectrum Scale 5.0.0 release ships new version of NFS server implementation (NFS Ganesha). It has 2 new features: nfsrmlock utility, and Support for dynamic change in client definition of NFS export.
This new utility releases NFS locks held by NFS server on behalf of orphaned NFSv3 client. There are situations where NFSv3 client is not available (due to h/w failure or any other disaster). In such cases, the locks requested by that client will be remain held by NFS server forever. These locks could not be available to other NFS clients. As the client is not available to release the locks, “nfsrmlock” utility helps in releasing those locks. “nfsrmlock” asks the NFS server to release all the locks held on behalf of that NFSv3 client.
Support for dynamic change in client definition of NFS export
This new feature allows system administrator to dynamically modify the client definition for NFS export. This means no restart of NFS Ganesha server for every change in client definition of an export. This results in avoiding invocation of grace period on all CES NFS servers for every such export change.
More about grace period
With every restart, the NFS server looses track of the locks, open files states(NFSv4) during its previous run. So on every startup (start/restart), NFS server enters into grace period. The grace period allows the connected NFS clients to reclaim their locks and open files state (NFSv4). By default the grace period in Spectrum Scale is 60 seconds. During grace period, only reclaim operations are permitted. New locks are not issued for the NFS client (both NFSv3 and NFSv4 clients). For NFSv4 clients additionally, opening of a new file, deleting a file, renaming a file and setting attributes on the file is also prohibited.
– by NFS Ganesha Team (Malahal, Madhu, Ravi, Sachin)