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)

SEE ALSO

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

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

Linux                                               JULY 2012                                       NFSIOSTAT(1)