NS0-593 Exam Dumps : NetApp Certified Support Engineer ONTAP Specialist

The maxdirsize is the maximum size of a directory in a FlexVol or FlexGroup volume. It is determined by the number of inodes allocated to the directory. If the directory contains more files than the maxdirsize can accommodate, then the ONTAP software will return an out of space error message to the host, even if the volume has enough free space. This can happen when a FlexGroup volume has a flat directory structure with millions of files, as the maxdirsize is not automatically adjusted for FlexGroup volumes12. References: 1: FlexGroup volumes: Frequentlyasked questions | NetApp Documentation 2: How to increase the maxdirsize of a FlexVol volume - NetApp Knowledge Base

• IQN stands for iSCSI Qualified Name, which is a unique identifier for an iSCSI initiator or target1.
• ONTAP uses IQN to authenticate and authorize iSCSI sessions2.
• If two hosts have the same IQN, they will cause a conflict and ONTAP will reject the new session request from the second host3.
• This will result in the host losing the connection to the iSCSI target and then reporting that the session was reestablished, as shown in the exhibit.
• To avoid this problem, each host should have a unique IQN. References:
• iSCSI Qualified Name (IQN) - NetApp
• iSCSI authentication and authorization - NetApp
• Troubleshooting iSCSI issues - NetApp
• [Configuring iSCSI initiators - NetApp]

• NFSv4 is a network file system protocol that supports security, performance, and scalability features. NFSv4 uses ID mapping to ensure that the permissions of files and directories are consistent across different NFSv4 servers and clients1
• ID mapping is the process of translating the user and group identifiers (UIDs and GIDs) of the local system to the user and group names (user@domain and group@domain) of the remote system, and vice versa. ID mapping is done by the idmapd service, which uses the /etc/idmapd.conf file to determine the domain name of the system2
• ID mapping requires that the NFSv4 server and client have the same domain name configured in the /etc/idmapd.conf file. If the domain names do not match, the idmapd service cannot map the UIDs and GIDs to the user and group names, and the permissions of the files and directories will be shown as nobody:nobody, which is the default anonymous user3
• Therefore, if a customer enabled NFSv4.0 on an SVM and changed the client mount from NFSv3 to NFSv4, and found that the directory owner was changed from root to nobody, the most likely cause is that the ID mapping domains do not match between the client and server. The customer should check and correct the /etc/idmapd.conf file on both systems, and restart the idmapd service and remount the NFSv4 share4

References:

1: ONTAP 9 - Network File System (NFS) - The Open Group 2: ONTAP 9 - NFSv4 and NFSv4.1 Enhancements - The Open Group 3: NFSv4 mount incorrectly shows all files with ownership as nobody:nobody - Red Hat Customer Portal 4: NFSv4 mountpoint shows incorrect ownerships as nobody:nobody in CentOS/RHEL - The Geek Diary