This section describes the commands you can use for troubleshooting NFS problems.
This command displays statistical information about NFS and RPC connections. Use the following syntax to display NFS server and client statistics:
Displays client-side information.
Displays statistics for each NFS-mounted file system.
Displays the NFS information on both the client side and the server side.
Displays RPC statistics.
Displays the server-side information.
Specifies that the statistics should be set to zero.
If no options are supplied, the –cnrs options are used.
Gathering server-side statistics can be important for debugging problems when new software or new hardware is added to the computing environment. Running this command a minimum of once a week, and storing the numbers, provides a good history of previous performance.Example 10 Displaying NFS Server Statistics
$ nfsstat -s Server rpc: Connection oriented: calls badcalls nullrecv badlen xdrcall dupchecks dupreqs 719949194 0 0 0 0 58478624 33 Connectionless: calls badcalls nullrecv badlen xdrcall dupchecks dupreqs 73753609 0 0 0 0 987278 7254 Server NFSv2: calls badcalls referrals referlinks 25733 0 0 0 Server NFSv3: calls badcalls referrals referlinks 132880073 0 0 0 Server NFSv4: calls badcalls referrals referlinks 488884996 4 0 0 Version 2: (746607 calls) null getattr setattr root lookup readlink read 883 0% 60 0% 45 0% 0 0% 177446 23% 1489 0% 537366 71% wrcache write create remove rename link symlink 0 0% 1105 0% 47 0% 59 0% 28 0% 10 0% 9 0% mkdir rmdir readdir statfs 26 0% 0 0% 27926 3% 108 0% Version 3: (728863853 calls) null getattr setattr lookup access 1365467 0% 496667075 68% 8864191 1% 66510206 9% 19131659 2% readlink read write create mkdir 414705 0% 80123469 10% 18740690 2% 4135195 0% 327059 0% symlink mknod remove rmdir rename 101415 0% 9605 0% 6533288 0% 111810 0% 366267 0% link readdir readdirplus fsstat fsinfo 2572965 0% 519346 0% 2726631 0% 13320640 1% 60161 0% pathconf commit 13181 0% 6248828 0% Version 4: (54871870 calls) null compound 266963 0% 54604907 99% Version 4: (167573814 operations) reserved access close commit 0 0% 2663957 1% 2692328 1% 1166001 0% create delegpurge delegreturn getattr 167423 0% 0 0% 1802019 1% 26405254 15% getfh link lock lockt 11534581 6% 113212 0% 207723 0% 265 0% locku lookup lookupp nverify 230430 0% 11059722 6% 423514 0% 21386866 12% open openattr open_confirm open_downgrade 2835459 1% 4138 0% 18959 0% 3106 0% putfh putpubfh putrootfh read 52606920 31% 0 0% 35776 0% 4325432 2% readdir readlink remove rename 606651 0% 38043 0% 560797 0% 248990 0% renew restorefh savefh secinfo 2330092 1% 8711358 5% 11639329 6% 19384 0% setattr setclientid setclientid_confirm verify 453126 0% 16349 0% 16356 0% 2484 0% write release_lockowner illegal 3247770 1% 0 0% 0 0% Server nfs_acl: Version 2: (694979 calls) null getacl setacl getattr access getxattrdir 0 0% 42358 6% 0 0% 584553 84% 68068 9% 0 0% Version 3: (2465011 calls) null getacl setacl getxattrdir 0 0% 1293312 52% 1131 0% 1170568 47%
The example shows how to display the statistics for RPC and NFS activities. In both sets of statistics, knowing the average number of badcalls or calls and the number of calls per week can help identify a problem. The badcalls value reports the number of bad messages from a client. This value can indicate network hardware problems.
Some of the connections generate write activity on the disks. A sudden increase in these statistics could indicate trouble and should be investigated. For NFS Version 2 statistics, the connections to note are setattr, write, create, remove, rename, link, symlink, mkdir, and rmdir. For NFS Version 3 and NFS Version 4 statistics, the value to watch is commit. If the commit level is high in one NFS server compared to another almost identical server, check that the NFS clients have enough memory. The number of commit operations on the server grows when clients do not have available resources.
The pstack command displays a stack trace for each process. The pstack command must be run by the owner of the process or by root. You can use the pstack command to determine where a process is hung. The only option that is allowed with this command is the process ID of the process that you want to check. For more information about the pstack command, see the proc(1) man page.Example 11 Displaying Stack Trace for NFS Process
$ /usr/bin/pgrep nfsd 243 $ /usr/bin/pstack 243 243: /usr/lib/nfs/nfsd -a 16 ef675c04 poll (24d50, 2, ffffffff) 000115dc ???????? (24000, 132c4, 276d8, 1329c, 276d8, 0) 00011390 main (3, efffff14, 0, 0, ffffffff, 400) + 3c8 00010fb0 _start (0, 0, 0, 0, 0, 0) + 5c
The example shows that the process is waiting for a new connection request, which is a normal response. If the stack shows that the process is still in poll after a request is made, the process might be hung. For more information about fixing a hung process, see How to Restart NFS Service. For more information about troubleshooting NFS, see NFS Troubleshooting Procedures.
The rpcinfo command generates information about the RPC service that is running on a system. Use the following command syntaxes to display information about the RPC service:
rpcinfo [-m|-s] [hostname] rpcinfo [-T transport] [hostname] [progname] rpcinfo [-t|-u] [hostname] [progname]
Displays a table of statistics of the rpcbind operations
Displays a concise list of all registered RPC programs
Displays information about services that use specific transports or protocols
Probes the RPC programs that use TCP
Probes the RPC programs that use UDP
Specifies the transport or protocol for the services
Specifies the host name of the server
Specifies the name of the RPC program
For more information about the available options, see the rpcinfo(1M) man page.
If no value is given for hostname, the local host name is used. You can substitute the RPC program number for progname, but the name is more commonly used. You can use the –p option in place of the –s option on those systems that do not run the NFS Version 3 software.
The data that is generated by this command can include the following:
RPC program number
Version number for a specific program
Transport protocol in use
Name of the RPC service
Owner of the RPC service
$ rpcinfo -s bee |sort -n program version(s) netid(s) service owner 100000 2,3,4 udp6,tcp6,udp,tcp,ticlts,ticotsord,ticots portmapper superuser 100001 4,3,2 udp6,udp,ticlts rstatd superuser 100003 4,3,2 tcp,udp,tcp6,udp6 nfs 1 100005 3,2,1 ticots,ticotsord,tcp,tcp6,ticlts,udp,udp6 mountd superuser 100007 1,2,3 ticots,ticotsord,ticlts,tcp,udp,tcp6,udp6 ypbind 1 100011 1 udp6,udp,ticlts rquotad superuser 100021 4,3,2,1 tcp,udp,tcp6,udp6 nlockmgr 1 100024 1 ticots,ticotsord,ticlts,tcp,udp,tcp6,udp6 status superuser 100068 5,4,3,2 ticlts - superuser 100083 1 ticotsord - superuser 100133 1 ticots,ticotsord,ticlts,tcp,udp,tcp6,udp6 - superuser 100134 1 ticotsord - superuser 100155 1 ticotsord smserverd superuser 100169 1 ticots,ticotsord,ticlts - superuser 100227 3,2 tcp,udp,tcp6,udp6 nfs_acl 1 100234 1 ticotsord - superuser 390113 1 tcp - superuser 390435 1 tcp - superuser 390436 1 tcp - superuser 1073741824 1 tcp,tcp6 - 1
The example shows information about the RPC services that are running on a server. The output that is generated by the command is filtered by the sort command by program number to make the information more readable. Several lines that list RPC services have been deleted from the example.
You can gather information about a particular RPC service by selecting a particular transport on a server. The following example checks the mountd service that is running over TCP.
$ rpcinfo -t bee mountd program 100005 Version 1 ready and waiting program 100005 Version 2 ready and waiting program 100005 Version 3 ready and waiting
The following example checks the NFS service that is running over UDP.
$ rpcinfo -u bee nfs program 100003 Version 2 ready and waiting program 100003 Version 3 ready and waiting
The snoop command is used to monitor packets on the network. The snoop command must be run as the root user. The use of this command is a good way to ensure that the network hardware is functioning on both the NFS client and the NFS server.
Use the following command syntax to monitor packets on the network:
snoop [-d device] [-o filename] [host hostname]
Specifies the local network interface
Stores all the captured packets into the named file
Displays packets going to and from a specific host only
The –d device option is useful on servers that have multiple network interfaces. You can use many expressions other than setting the host. A combination of command expressions with grep can often generate data that is specific enough to be useful. For more information about the available options, see the snoop(1M) man page.
When troubleshooting, make sure that packets are going to and from the proper host. Also, look for error messages. Saving the packets to a file can simplify the review of the data.
You can use the truss command to check whether a process is hung. The truss command must be run by the owner of the process or by root.
Use the following command syntax to check whether a process is hung:
truss [-t syscall] -p pid
Selects system calls to trace
Indicates the PID of the process to be traced
syscall is a comma-separated list of system calls to be traced. Starting the list with an ! character excludes the listed system calls from the trace. For more information about the available options, see the truss(1) man page.Example 13 Displaying Process Status
$ /usr/bin/truss -p 243 poll(0x00024D50, 2, -1) (sleeping...)
The example shows that the process is waiting for another connection request, which is a normal response. If the response does not change after a new connection request has been made, the process could be hung.