Ubuntu Manpage: nfsiostat - Report input/output statistics for network filesystems (NFS).

NAME

       nfsiostat - Report input/output statistics for network filesystems (NFS).

SYNOPSIS

       nfsiostat [ -h ] [ -k | -m ] [ -t ] [ -V ] [ interval [ count ] ]

DESCRIPTION

       The  nfsiostat  command  displays  statistics  about  read  and  write  operations  on NFS
       filesystems.

       The interval parameter specifies the amount of time in seconds between  each  report.  The
       first report contains statistics for the time since system startup (boot). Each subsequent
       report contains statistics collected during the interval since  the  previous  report.   A
       report  consists  of  an  NFS header row followed by a line of statistics for each network
       filesystem that is mounted.  The count parameter can be specified in conjunction with  the
       interval parameter. If the count parameter is specified, the value of count determines the
       number of reports generated at interval  seconds  apart.  If  the  interval  parameter  is
       specified   without   the   count  parameter,  the  nfsiostat  command  generates  reports
       continuously.

REPORT

The Network Filesystem (NFS) report provides statistics for each mounted network
filesystem. Transfer rates are shown in 1K blocks by default, unless the environment
variable POSIXLY_CORRECT is set, in which case 512-byte blocks are used. The report shows
the following fields:

Filesystem:
This columns shows the hostname of the NFS server followed by a colon and by the
directory name where the network filesystem is mounted.

rBlk_nor/s (rkB_nor/s, rMB_nor)
Indicate the number of blocks (kilobytes, megabytes) read by applications via the
read(2) system call interface. A block has a size of 512 bytes.

wBlk_nor/s (wkB_nor/s, wMB_nor/s)
Indicate the number of blocks (kilobytes, megabytes) written by applications via
the write(2) system call interface.

rBlk_dir/s (rkB_dir/s, rMB_dir/s)
Indicate the number of blocks (kilobytes, megabytes) read from files opened with
the O_DIRECT flag.

wBlk_dir/s (wkB_dir/s, wMB_dir/s)
Indicate the number of blocks (kilobytes, megabytes) written to files opened with
the O_DIRECT flag.

rBlk_svr/s (rkB_svr/s, rMB_svr/s)
Indicate the number of blocks (kilobytes, megabytes) read from the server by the
NFS client via an NFS READ request.

wBlk_svr/s (wkB_svr/s, wMB_svr/s)
Indicate the number of blocks (kilobytes, megabytes) written to the server by the
NFS client via an NFS WRITE request.

ops/s
Indicate the number of operations that were issued to the filesystem per second.

rops/s
Indicate the number of 'read' operations that were issued to the filesystem per
second.

wops/s
Indicate the number of 'write' operations that were issued to the filesystem per
second.

OPTIONS

       -h     Make the NFS report easier to read by a human.

       -k     Display statistics in kilobytes per second.

       -m     Display statistics in megabytes per second.

       -t     Print the time for each report displayed. The timestamp format may  depend  on  the
              value of the S_TIME_FORMAT environment variable (see below).

       -V     Print version number then exit.

ENVIRONMENT

       The nfsiostat command takes into account the following environment variables:

       S_TIME_FORMAT
              If  this  variable  exists  and  its  value  is ISO then the current locale will be
              ignored when printing the date in the report header. The nfsiostat command will use
              the  ISO  8601 format (YYYY-MM-DD) instead.  The timestamp displayed with option -t
              will also be compliant with ISO 8601 format.

       POSIXLY_CORRECT
              When this variable is set, transfer rates are shown in 512-byte blocks  instead  of
              the default 1K blocks.

BUG

       /proc filesystem must be mounted for nfsiostat to work.

FILE

       /proc/self/mountstats contains statistics for network filesystems.

AUTHORS

       Written by Ivana Varekova (varekova <at> redhat.com)

       Maintained by Sebastien Godard (sysstat <at> orange.fr)