NFS

Introduction

Network File System (NFS) is an industry standard protocol to share files over a network. The Sun ZFS Storage Appliance supports NFS versions 2, 3, and 4. For more information on how the filesystem namespace is constructed, see the filesystem namespace section.

Properties

Property Description Minimum supported version Use this drop-down list to control which versions of NFS the appliance supports. Maximum supported version Use this drop-down list to control which versions of NFS the appliance supports. Maximum # of server threads Define the maximum number of concurrent NFS requests (from 20 to 1000). This should at least cover the number of concurrent NFS clients that you anticipate. Grace period Define the number of seconds that all clients have to recover locking state after an appliance reboot (from 15 to 600 seconds) from an unplanned outage. This property affects only NFS v4 clients (NFS v3 is stateless so there is no state to reclaim). During this period, the NFS service only processes reclaims of the old locking state. No other requests for service are processed until the grace period is over. The default grace period is 90 seconds. Reducing the grace period lets NFS clients resume operation more quickly after a server reboot, but increases the probability that a client cannot recover all of its locking state. The Oracle ZFS Storage Appliance provides grace-less recovery of the locking state for NFSv4 clients during planned outages. Planned outages occur during events such as rolling upgrade, and appliance reboot using the CLI maintenance system reboot command, or rebooting using the BUI power icon . For planned outages, the NFS service processes all requests for service without incurring the grace period delay. Custom NFSv4 identity domain Use this property to define the domain for mapping NFSv4 users and group identities. If you do not set this property, the appliances uses DNS to obtain the identity domain, first by checking for a _nfsv4idmapdomain DNS resource record, and then by falling back to the DNS domain itself. Enable NFSv4 delegation Select this property to allow clients to cache files locally and make modifications without contacting the server. This option is enabled by default and typically results in better performance; but in rare circumstances it can cause problems. You should only disable this setting after careful performance measurements of your particular workload and after validating that the setting has a measurable performance benefit. This option only affects NFSv4 mounts. Kerberos realm A realm is logical network, similar to a domain, that defines a group of systems that are under the same master KDC. Realm names can consist of any ASCII string. Usually, your realm name is the same as your DNS domain name, except that the realm name is in uppercase. Using this convention helps you differentiate problems with the Kerberos service from problems with the DNS namespace, while still using a name that is familiar. Kerberos master KDC In each realm, you must include a server that maintains the master copy of the principal database. The most significant difference between a master KDC and a slave KDC is that only the master KDC handles database administration requests. For instance, you must change a password or add a new principal on the master KDC. Kerberos slave KDC The slave contains duplicate copies of the principal database. Both the master KDC server and the slave KDC server create tickets that are used to establish authentication. Kerberos admin principal This property identifies the client. By convention, a principal name is divided into three components: the primary, the instance, and the realm. You can specify a principal as joe, joe/admin, or joe/admin@ENG.EXAMPLE.COM. Kerberos admin password Define the password for the admin principal. Oracle Intelligent Storage Protocol The NFSv4 service includes support for the Oracle Intelligent Storage Protocol, which lets Oracle Database NFSv4 clients pass optimization information to the ZFS Storage Appliance NFSv4 server. For more information, see Oracle Intelligent Storage Protocol.

Changing services properties is documented in the BUI and CLI sections of Services.

Setting the NFS minimum and maximum versions to the same value causes the appliance to only communicate with clients using that version. This may be useful if you find an issue with one NFS version or the other (such as the performance characteristics of an NFS version with your workload), and you want to force clients to only use the version that works best.

Kerberos Realms

Configuring a Kerberos realm creates certain service principals and adds the necessary keys to the system's local keytab. The NTP service must be configured before configuring Kerberized NFS. The following service principals are created and updated to support Kerberized NFS:

host/node1.example.com@EXAMPLE.COM
nfs/node1.example.com@EXAMPLE.COM

If you clustered your appliances, principals and keys are generated for each cluster node:

host/node1.example.com@EXAMPLE.COM
nfs/node1.example.com@EXAMPLE.COM
host/node2.example.com@EXAMPLE.COM
nfs/node2.example.com@EXAMPLE.COM

If these principals have already been created, configuring the realm resets the password for each of those principals. If you configured your appliance to join an Active Directory domain, you cannot configure it to be part of a Kerberos realm.

For information on setting up KDCs and Kerberized clients, see http://docs.oracle.com/cd/E26502_01/html/E29015/index.html. After setting NFS properties for Kerberos, change the Security mode on the Shares->Filesystem->Protocols screen to a mode using Kerberos.

The following ports are used by the appliance for Kerberos.

• Kerberos V authentication: 88

• Kerberos V change and set password SET_CHANGE: 464

• Kerberos V change and set password RPCSEC_GSS: 749

Note: Kerberized NFS clients must access the appliance using an IP address that resolves to an FQDN for those principals. For example, if an appliance is configured with multiple IP addresses, only the IP address that resolves to the appliance's FQDN can be used by its Kerberized NFS clients.

Logs

These logs are available for the NFS service:

To view service logs, refer to the Logs section from Services.

Analytics

You can monitor NFS activity in the Analytics section. This includes:

• NFS operations per second

• ... by type of operation (read/write/...)

• ... by share name

• ... by client hostname

• ... by accessed filename

• ... by access latency

Note: When the NFS server reboots or fails over the filename is unknown at the server until a new open from the client. The file appears as unknown in Analytics worksheets.

CLI

The following table describes the mapping between CLI properties and the BUI property descriptions above.

Tasks

NFS Tasks

Sharing a Filesystem over NFS

1. Go to the Configuration->Services screen.
2. Check that the NFS service is enabled and online. If not, enable the service.
3. Got to the Shares screen and edit an existing share or create a new share.
4. Click the Protocols tab of the share you are editing and check that NFS sharing is enabled. You can also configure the NFS share mode (read/read+write) in this screen.