NFSIOSTAT(1)                                                    Linux User's Manual                                                   NFSIOSTAT(1)

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  con-
       sists of an NFS header row followed by a line of statistics for each network filesystem that is mounted.  The count parameter can be speci-
       fied 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  com-
              pliant 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)

SEE ALSO

       sar(1), pidstat(1), mpstat(1), vmstat(8), iostat(1), cifsiostat(1)

       http://pagesperso-orange.fr/sebastien.godard/

Linux                                                              JANUARY 2011                                                       NFSIOSTAT(1)