Client attribute syntax

Client attributes are described in Table 1.

Table 1. Client attributes
Attribute	Description
accesschk(Y\|N) Specifies whether the z/OS NFS client or NFS server is to check that the user has the requested access to the file or directory. If accesschk(Y) is specified, the z/OS NFS client performs the access check. If accesschk(N) is specified, the NFS server performs the access check. The accesschk attribute default value is: Y For mounts established with system authentication (sys) N For mounts established with RPCSEC_GSS authentication (krb5, krb5i, or krb5p)
acdirmax(n) Specifies the maximum lifetime in seconds of cached directory attributes. The acdirmax attribute default value is 60.
acdirmin(n) Specifies the minimum lifetime in seconds of cached directory attributes. The acdirmin attribute default value is 30.
acregmax(n) Specifies the maximum lifetime in seconds of cached file attributes. The acregmax attribute default value is 60.
acregmin(n) Specifies the minimum lifetime in seconds of cached file attributes. The acregmin attribute default value is 3.
attrcaching(Y\|N) Specifies whether to process attributes and data caching. If attribute caching is in effect, the z/OS NFS client maintains cache consistency with the copy of the file on the NFS server by performing the consistency check with the cached file attributes. When a file's data is read, it remains valid on the z/OS NFS client until the attribute cache is timed out or negated. If attrcaching(N) is specified, it will automatically set datacaching(N). The attrcaching attribute default value is: Y For mounts established with system authentication (sys) N For mounts established with RPCSEC_GSS authentication (krb5, krb5i, or krb5p) Note: attrcaching is not supported for Kerberos mounts (for example, krb5, krb5i, or krb5p). It is only supported for system authentication (sys) mounts. Specifying attrcaching(Y) is ignored with RPCSEC_GSS mounts.
biod(n) Specifies the number of asynchronous block input/output (I/O) daemons. The BIOD daemon runs on all NFS client systems. When a user on a client wants to read or write to a file on a server, the BIOD daemon sends this request to the server. The BIOD daemon is activated during system startup and runs continuously. The number of daemons is based on the load the client can handle. Six to eight daemons can handle an average load. You must run at least one daemon for NFS to work. The valid range is 1 to 32. The biod attribute default value is 6.
bufhigh(n) Specifies the storage limit for data buffers for the NFS client. The valid range is 4 MB to 1 GB. The bufhigh attribute default is 128 MB.
cln_ccsid(x) Specifies the coded character set identifier (CCSID) for the local mounted file system. The cln_ccsid attribute default is 1047 (LATIN OPEN SYSTEM EBCDIC).
*convserv(technique)* Specifies the conversion technique-search-order that Unicode Services will use for specified srv_ccsid(x) and cln_ccsid(x) code pages. Technique consists of up to five technique-characters corresponding to the available techniques: R, E, C, L and M. See z/OS Unicode Services User's Guide and Reference for detailed descriptions on these conversion techniques. NFS version 4 protocol (NFSv4) differs from NFSv2 and NFSv3 protocol in handling single to multiple byte conversion. Therefore, the technique-search-order specified in the convserv() attribute should consider the effects of the NFS protocol being used. SeeCreating the conversion environment for Unicode Services for further details. The convserv default is LRE.
datacaching(Y\|N) Specifies whether to perform data caching. The datacaching attribute provides finer granularity in controlling whether file data should be cached by the z/OS NFS client. By caching the file data, all subsequent references to the cached data is done locally thus avoiding the network overhead. This has additional significance when obtaining data from NFS server systems which do not use UNIX access permissions for security as there is a potential security exposure allowing unauthorized users to access file data. The datacaching attribute default value is: Y For mounts established with system authentication (sys) N For mounts established with RPCSEC_GSS authentication (krb5, krb5i, or krb5p) Note: datacaching is not supported for Kerberos mounts (for example, krb5, krb5i, or krb5p). It is only supported for system authentication (sys) mounts. Specifying datacaching(Y) is ignored with RPCSEC_GSS mounts. During mount , datacaching is turned off when security negotiation was attempted such that security was negotiated from sys to any of the krb flavors. If attrcaching(N) is specified, it will automatically set datacaching(N).
delaywrite(n) Specifies the maximum number of disk blocks for delay write. The valid range is 0 to 32. The delaywrite attribute default value is 16. The blocksize is 8192. This option is valid only when datacaching=Y.
delim (na\|binary\|nl\|cr\|lf\|crlf\|lfcr) Specifies the line delimiter for record access to remote files through the basic sequential access method (BSAM), queued sequential access method (QSAM), and virtual storage access method (VSAM). na Not specified. This value applies when the delim attribute is omitted. Note that this value must not be specified on the delim attribute. na can be specified only by omitting the delim attribute from the parameter list. binary Specifies the data does not have record delimiters. The access method does not add a delimiter for each record on output and treats any delimiters on input as data. The following text options can be specified: cr Specifies that records are delimited by the EBCDIC carriage return character (x'0D'). crlf Specifies that records are delimited by the EBCDIC carriage return character followed by the EBCDIC line feed character (x'0D25'). crnl Specifies that records are delimited by the EBCDIC carriage return character followed by the EBCDIC new line character (x'0D15'). lf Specifies that records are delimited by the EBCDIC line feed character (x'25'). lfcr Specifies that records are delimited by the EBCDIC line feed character followed by the EBCDIC carriage return character (x'250D'). nl Specifies that records are delimited by the EBCDIC new line character (x'15').
disablella(Y\|N) Specifies the disabling or enabling of Lookup Look-Aside (LLA) caching. The enabling of LLA cache with disablella(N) provides better performance, but may cause data integrity issues in a Shared File System sysplex or a network environment if file objects are altered by more than one system in the sysplex or network. The disabling of LLA cache with disablella(Y) causes more LOOKUP requests from z/OS NFS client to z/OS NFS Server, thus affecting performance but guaranteeing data integrity. This is the recommended setting in a Shared File System sysplex environment or a network environment. See z/OS UNIX System Services File System Interface Reference for further details on the use of disablella.
dynamicsizeadj(Y\|N) Specifies whether to perform the packet size adjustment for remote procedure call (RPC). The dynamicsizeadj attribute default value is Y.
llock(Y\|N) Specifies whether file locking requests are managed on your local z/OS UNIX file system or remotely on the NFS Server. Y the local Byte Range Lock Manager ( BRLM ) manages the lock. N The z/OS NFS Client sends various NFS Version 4 locking operations to the remote NFS Server to manage the file lock requests. The z/OS NFS Client and other participating NFS Clients can perform Byte Range Locking on the remote files at the supported NFS Server. The llock attribute default value is N. Note: This attribute is valid only for the NFS Version 4 protocol. If the NFS mounted file system is NFS Version 2 or 3 or if the NFS Server does not support the NFS Version 4 Locking then /usr/lpp/NFS/nfsstat will report llock(y).
*nfsv4domain(NFSv4_default_domain)* Specifies the default domain for the NFS v4 protocol (NFSv4) name mapping. The nfsv4domain attribute serves for redefinition of a name of this unique domain. In accordance with RFC3530 NFSv4 attributes "owner"and "owner_group"are transferred between the client and server in the form of "user_name@domain"and "group_name@domain". The client provides the mapping of names to id’s and vice versa. NFSv4_default_domain identifies the user/group name space with one to one correspondence between the names and their numeric identifiers (uid’s and gid’s). z/OS NFS Client will accept as valid a set of users and groups for default domain. The client will treat other domains as having no valid translations. If the nfsv4domain attribute is not used, the client uses the system-defined domain. The NFSv4_default_domain will be converted internally to lower case. For further details on NFSv4 name mapping, see NFS v4 protocol name mapping.
proto(tcp\|udp) Specifies the transport protocol for the NFS client to communicate with the NFS server. By default, the NFS client selects the proto and vers with the following priorities: proto(tcp) and vers(4) proto(tcp) and vers(3) proto(udp) and vers(3) proto(tcp) and vers(2) proto(udp) and vers(2) Note: proto(udp) is functionally equivalent to secure(udp) proto(udp) is mutually exclusive with the vers(4) parameter. proto(udp) is valid only for the NFS Version 2 and Version 3 protocols. If proto(tcp) and secure(udp) are both in effect as mount parameters, proto(tcp) is ignored.
public Forces the use of the public file handle when connecting to the NFS server. This option is valid only during mount processing. The public keyword is valid only for the NFS version 4 protocol.
readahead(n) Specifies the maximum number of disk blocks to read ahead. The block size is 8192 bytes. The valid range is 0 to 16. The readahead attribute default value is 1.
retrans(n) Specifies the number of times to retransmit the NFS remote procedure calls (RPC). The valid range is 0 to 1000. The retrans attribute default value is 3. This option is valid only when soft and proto(upd) are specified.
retry(n) Specifies the number of times to retry the mount operation. The valid range is 0 to 20,000. The retry attribute default value is 10. This option is valid only during mount processing.
rsize(n) Sets the read buffer size in n bytes. The valid range is 1 to 8192. For NFS NFSv2 mounts, the rsize attribute default value is 8192. For NFSv3 or NFSv4 mounts, the rsize attribute value is negotiated between the z/OS NFS client and the NFS server. The maximum write buffer size supported by the z/OS NFS client is 32 KB. The specification of an rsize attribute of any value will override the negotiated buffer size and result in a default buffer size of 8192.
rpcbind(Y\|N) Specifies whether the target NFS server platform supports the RPCBIND protocol, so the NFS client will not have to attempt to use the RPCBIND protocol if that protocol is not supported. The default is rpcbind(Y), to indicate that RPCBIND is supported. If N is specified, the z/OS NFS Client will immediately use the PORTMAPPER protocol instead. This keyword has no effect if the client system is not enabled for IP version 6 (IPv6). The rpcbind default value is Y.
secure(sys \| krb5 \| krb5i \| krb5p \| udp) Specifies the transport protocol for the NFS client to use to bind reserved (privileged) ports when communicating to the NFS server. Note: secure(sys) uses the system authentication. secure(krb5) provides Kerberos V5 based integrity on the RPC credentials (but not data) using the DES_MAC_MD5 integrity algorithm and uses the RPCSEC_GSS service of rpc_gss_svc_none. secure(krb5) is valid only for the NFS Version 4 protocol. secure(krb5i) provides Kerberos V5 based integrity on both the RPC credentials and data using the DES_MAC_MD5 integrity algorithm and uses the RPCSEC_GSS service of rpc_gss_svc_integrity. secure(krb5i) is valid only for the NFS Version 4 protocol. secure(krb5p) provides Kerberos V5 based integrity and privacy on both the RPC credentials and data using the DES_MAC_MD5 algorithm for integrity and 56 bit DES for privacy. It uses the RPCSEC_GSS service of rpc_gss_svc_privacy. secure(krb5p) is valid only for the NFS Version 4 protocol. secure(udp) is functionally equivalent to proto(udp). If secure(udp) is specified, proto(tcp) is ignored and the NFS client uses udp as the transport protocol to communicate with the NFS server. secure(udp) is mutually exclusive with the vers(4) parameter. secure(udp) is valid only for the NFS Version 2 and Version 3 protocols. During mount when sys,krb5,krb5i or krb5p is specified in the secure keyword, the client does not attempt a security negotiation.
soft\|hard Returns an error if the NFS server does not respond or continues to retry the NFS remote procedure call (RPC) until the NFS server responds. If hard is specified, the NFS remote procedure call (RPC) is retried until the NFS server responds. If soft is specified, an error is returned if the NFS server does not respond. The maximum number of retries is specified with the retrans option. This option is valid for all NFS RPCs under the mount point.
srv_ccsid(x) Specifies the coded character set identifier (CCSID) for the remote mounted file system. The srv_ccsid attribute default value is 819 (ISO 8859–1 ASCII).
stringprep(Y\|N) Specifies whether z/OS NFS Client is to enable or disable stringprep normalization. Stringprep normalization is the NFS version 4 globalization function for converting inbound strings to UTF-8 format. The stringprep attribute default value is N.
timeo(n) Sets the remote procedure call (RPC) timeout to n tenths of a second. The timeo attribute default value is 7.
vers(2\|3\|4) Specifies the NFS protocol version that the client will use to communicate with the NFS server. If no version is specified, the z/OS NFS client will communicate with the NFS server at the highest protocol level that is supported by the server.
wsize(n) Sets the write buffer size to n bytes. The valid range for n is 1 to 8192. The wsize attribute default value is 8192. For NFSv3 or NFSv4 mounts, the wsize attribute value is negotiated between the z/OS NFS client and the NFS server. The maximum write buffer size supported by the z/OS NFS client is 32 KB. The specification of a wsize attribute of any value will override the negotiated buffer size and result in a default buffer size of 8192.
xlat(Y\|N) If Y is specified, the data in all the files are text and the NFS client will perform data conversion according to the cln_ccsid and srv_ccsid parameters. The xlat attribute default value is N and should be used for binary data.