The following example shows output from the netstat -r command, which displays the IP routing table.
Routing Table: Destination Gateway Flags Ref Use Interface ------------------ -------------------- ----- ----- ------ --------- localhost localhost UH 0 2817 lo0 earth-bb pluto U 3 14293 le0 224.0.0.0 pluto U 3 0 le0 default mars-gate UG 0 14142 |
The fields in the netstat -r report are described in Table 46-2.
Table 46-2 Output From the netstat -r Command
Field Name |
| Description |
|---|---|---|
Flags | U G H D | The route is up. The route is through a gateway. The route is to a host. The route was dynamically created by using a redirect. |
Ref |
| Shows the current number of routes that share the same link layer. |
Use |
| Indicates the number of packets that were sent out. |
Interface |
| Lists the network interface that is used for the route. |
How to Display NFS Server and Client Statistics
The NFS distributed file service uses a remote procedure call (RPC) facility that translates local commands into requests for the remote host. The remote procedure calls are synchronous. That is, the client application is blocked or suspended until the server has completed the call and returned the results. One of the major factors affecting NFS performance is the retransmission rate.
If the file server cannot respond to a client's request, the client retransmits the request a specified number of times before it quits. Each retransmission imposes system overhead and increases network traffic. Excessive retransmissions can cause network performance problems. If the retransmission rate is high, you could look for the following:
Overloaded servers that take too much time to complete requests
An Ethernet interface that is dropping packets
Table 46-3 describes the nfsstat options to display client and server statistics.
Table 46-3 Commands for Displaying Client/Server Statistics
Command | Display |
|---|---|
nfsstat -c | Client statistics |
nfsstat -s | Server statistics |
netstat -m | Network statistics for each file system |
Use nfsstat -c to show client statistics, and nfsstat -s to show server statistics. Use netstat -m to display network statistics for each file system. For more information, see nfsstat(1M).
Examples--Displaying NFS Server and Client Statistics
The following example displays RPC and NFS data for the client pluto.
$ nfsstat -c
Client rpc:
Connection oriented:
calls badcalls badxids timeouts newcreds badverfs timers
1595799 1511 59 297 0 0 0
cantconn nomem interrupts
1198 0 7
Connectionless:
calls badcalls retrans badxids timeouts newcreds badverfs
80785 3135 25029 193 9543 0 0
timers nomem cantsend
17399 0 0
Client nfs:
calls badcalls clgets cltoomany
1640097 3112 1640097 0
Version 2: (46366 calls)
null getattr setattr root lookup readlink read
0 0% 6589 14% 2202 4% 0 0% 11506 24% 0 0% 7654 16%
wrcache write create remove rename link symlink
0 0% 13297 28% 1081 2% 0 0% 0 0% 0 0% 0 0%
mkdir rmdir readdir statfs
24 0% 0 0% 906 1% 3107 6%
Version 3: (1585571 calls)
null getattr setattr lookup access readlink read
0 0% 508406 32% 10209 0% 263441 16% 400845 25% 3065 0% 117959 7%
write create mkdir symlink mknod remove rmdir
69201 4% 7615 0% 42 0% 16 0% 0 0% 7875 0% 51 0%
rename link readdir readdir+ fsstat fsinfo pathconf
929 0% 597 0% 3986 0% 185145 11% 942 0% 300 0% 583 0%
commit
4364 0%
Client nfs_acl:
Version 2: (3105 calls)
null getacl setacl getattr access
0 0% 0 0% 0 0% 3105 100% 0 0%
Version 3: (5055 calls)
null getacl setacl
0 0% 5055 100% 0 0%
|
The output of the nfsstat -c command is described in Table 46-4.
Table 46-4 Output From the nfsstat -c Command
Field | Description |
|---|---|
calls | The total number of calls that were sent. |
badcalls | The total number of calls that were rejected by RPC. |
retrans | The total number of retransmissions. For this client, the number of retransmissions is less than 1 percent (10 timeouts out of 6888 calls). These retransmissions might be caused by temporary failures. Higher rates might indicate a problem. |
badxid | The number of times that a duplicate acknowledgment was received for a single NFS request. |
timeout | The number of calls that timed out. |
wait | The number of times a call had to wait because no client handle was available. |
newcred | The number of times the authentication information had to be refreshed. |
timers | The number of times the time-out value was greater than or equal to the specified time-out value for a call. |
readlink | The number of times a read was made to a symbolic link. If this number is high (over 10 percent), it could mean that there are too many symbolic links. |
The following example shows output from the nfsstat -m command.
pluto$ nfsstat -m
/usr/man from pluto:/export/svr4/man
Flags: vers=2,proto=udp,auth=unix,hard,intr,dynamic,
rsize=8192, wsize=8192,retrans=5
Lookups: srtt=13 (32ms), dev=10 (50ms), cur=6 (120ms)
All: srtt=13 (32ms), dev=10 (50ms), cur=6 (120ms)
|
This output of the nfsstat -m command, which is displayed in milliseconds, is described in Table 46-5.
Table 46-5 Output From the nfsstat -m Command
Field | Description |
|---|---|
srtt | The smoothed average of the round-trip times |
dev | The average deviations |
cur | The current "expected" response time |
If you suspect that the hardware components of your network are creating problems, you need to look closely at the cabling and connectors.