Configuring NFSv4 Server

You can configure NFSv4 server by setting the values for the parameters in the /opt/mapr/conf/nfs4server.conf file. The configuration parameters are defined within blocks in the file. The following sections describe the blocks and required parameters (within each block) for the MapR NFSv4 server.

Contains the general settings for the daemon. The parameters in this block should not be modified.
Clustered The value is false. Do not modify this parameter.
Plugins_Dir The directory for the FSAL libraries. The value is /opt/mapr/lib. Do not modify this parameter.
DRC_TCP_Size The maximum number of results stored in the DRC. The default value is 16.
DRC_TCP_Recycle_Expire_S The amount of time after which to expire results stored in DRC. The default value is 60 seconds.
Dirent_Entries_Track Specifies whether (true) or not (false) to monitor dirent entries. If true, the process restarts if the number of dirent entries exceeds limit.
Num_Log_Files The maximum number of log files. The default value is 1.
Max_Logfile_Size The maximum amount of space for each log file. The default value is 1073741824. The total amount of disk space for log files is calculated using the following:
Num_Log_Files * Max_LogFile_Size
For example, suppose Num_Log_Files = 32 and Max_LogFile_Size = 1GB. Then, the total disk space for log files is 32GB.
Enable_RQUOTA Specifies whether (true) or not (false) to enable support for remote quotas. The default value is false.
NFS_Protocols The supported NFS protocols. The only supported value is 4.
Contains settings for NFSv4 protocol. The following parameter should not be modified.
Delegations boolean Specifies whether delegation is supported. The default value is false and should not be modified (cannot be set to true) as delegation is not supported.
Dirent_Cache_Threshold 128 The threshold for caching directory entries. If directory entries exceed threshold, the entries are not cached; caching is enabled only if entries are below this threshold.
Note: This should be used only if readdirplus is true.
Contains default values for all subsequent EXPORT blocks. The settings in subsequent EXPORT blocks can override these default values on a per export basis.
Anonymous_Uid The anonymous UID. The default value is -2, which is converted to a 32 bit unsigned integer (4294967294) when root squash is enabled.
Anonymous_Gid The anonymous GID. The default value is -2, which is converted to a 32 bit unsigned integer (4294967294) when root squash is enabled.
Protocols The supported NFS protocols. The default value is 4. This cannot be changed.
Contains settings for exporting a filesystem.
SecType The comma-separated list of supported authentication flavors for the export or the type of security. Value can be comma-separated list of:
  • krb5 — authentication
  • krb5i — integrity
  • krb5p — privacy
Note: This must be specified if you want the clients to use kerberos ticket for secure access.
Path (Required) The (cluster) path to export via NFS. The path should have a leading slash. If just /mapr is specified as the path, all the clusters (listed in the mapr-clusters.conf file) will be visible. To export only a specific cluster, specify the complete path to the cluster to export.
Note: Exporting will not be successful if extra forward slash (/) characters are in the path. For example, the following path will not be exported because of the extra slash (shown in bold) in the path: /mapr/Test3//ATS-VOLUME
Pseudo (Required for NFSv4 protocol for every directory or volume to export) The pseudo path, which when specified, masks the mount path from the NFS client, for the NFSv4 exports. MapR’s NFSv4 server provides a pseudo-file system where only the exported volumes are visible. This is especially useful in scenarios where one or more volumes in the hierarchy should be hidden and not be visible. When mounting with NFSv4, use the pseudo path. Value can be the volume or directory path.
Export_Id (Required) The tag used to set the ID for the export or the unique ID to associate with each export. Value should not be 0.
Note: The export ID associated with each export must be the same across all NFSv4 servers on the cluster.
Squash Specifies whether to enable or disable root squashing. By default, root squashing is disabled. If root squash is enabled, the values substituted for the root user will be anonymous user (Anonymous_Uid and Anonymouos_Gid); that is, the UID and GID of a file created will not be nfsnobody because the default value of -2 is converted to a 32 bit unsigned integer (4294967294) instead of the 16 bit equivalent (65534), which is the value of nfsnobody.
Access_Type (Required) The type of access on the mount point. Valid values include:
  • RO — for read-only mount point
  • RW — for read/write mount point
  • MDONLY — for read/write access to metadata only
  • MDONLY_RO — for read-only access to metadata only
FSAL (Required) The file system to use. Value must be MAPR to use the MapR Filesystem library, which contains the shared library (libMapRClient) and the callbacks.
Contains configuration for logging. The default log level is INFO. Value can be one of the following:
  • MAJ
  • CRIT
  • WARN
  • INFO
Contains configurations for NFS gateway access to MapR file system.
Parameter Default Value Description
log_path /opt/mapr/logs/nfs4 Path for the log files.
ra_sessions 5 Number of parallel read ahead sessions per client library ( Each open file acts as one read ahead session. For example, if value is set to 5, up to 5 files can have read ahead sessions per client library ( To disable read ahead sessions, set value to 0.
Note: The number of client libraries is 3 by default and cannot be configured.
flush_inline true Specifies whether or not to flush all writes inline. Value can be:
  • true — flush all writes inline
  • false — disable inline flushing
If enabled (default), writes are sent to server directly. If disabled, for all open files, the buffer is flushed automatically every 3 seconds or when it reaches 64KB.
fast_local_directio false Specifies whether to optimize or disable NFS client for local direct IO. Value can be:
  • true — optimize
  • false — disable
nfs_track_memory false Specifies whether to enable (true) or disable (false) memory tracking for NFS.
hb_interval 5 The interval (in seconds) for sending heartbeat to CLDB to allow CLDB to determine whether server is running. The CLDB will declare the NFS gateway dead when it loses about 8 heartbeats in a row and will trigger a failover.
req_threshold 5 The amount of time (in seconds) for processing requests. If the threshold is exceeded, warnings will be logged.
client_lib_path /tmp/nfs4 The location for the client library (libMapRClient).
Note: To install and use NFSv4 and FUSE-based POSIX client on the same node, ensure that the path for the client library for the NFSv4 and FUSE-based POSIX client is not /tmp. Specify a different location for the client libraries. For example, /tmp/nfs4lib.
readdirplus true Specifies whether (true) or not (false) to enable extended read from the directory. If enabled (true), each entry returns the name, the file ID, attributes (including the field), and file handle.
  • The libnfsidmap must be configured to use nsswitch, a translation mechanism for mapping names to IDs, in the /etc/idmapd.conf file.
  • The NFSv3 (mapr-nfsserver) nodes cannot failover to NFSv4 server nodes and vice versa. Ensure that different set of VIPs are assigned for NFSv3 and NFSv4 server nodes. When running the maprcli virtualip add command to set up VIPs, list the MACs of the respective nodes so that the failover works properly (this is necessary if both NFSv3 and NFSv4 are going to be set up for same cluster). The MACs should be mutually exclusive as both NFSv4 and NFSv3 servers cannot run on the same node.