cifsiostat

cifsiostat [ OPTIONS ] [ INTERVAL [ COUNT ] ]

-d
    Display the device utilization report. This is the default behavior if no unit option is specified.

-k
    Display statistics in kilobytes (KB) per second. This changes the unit of reported throughput from bytes to kilobytes.

-m
    Display statistics in megabytes (MB) per second. This changes the unit of reported throughput from bytes to megabytes.

-h
    Display a brief help message explaining the command's usage and options, then exit.

-V
    Display the version number of the cifsiostat command (and the sysstat package it belongs to), then exit.

INTERVAL
    Specifies the time in seconds between each report. If omitted, a single report containing statistics since system boot is displayed.

COUNT
    Specifies the number of reports to be generated. This parameter is only valid if INTERVAL is also specified.

cifsiostat is a command-line utility used for reporting CIFS (Common Internet File System), also known as SMB (Server Message Block), I/O statistics. It is part of the sysstat package, which provides various system performance monitoring tools for Linux.

Unlike iostat, which reports general block device I/O statistics, cifsiostat specifically focuses on I/O operations related to mounted CIFS network shares. It provides metrics such as read/write operations per second, read/write bytes per second, and read/write request sizes for each active CIFS mount point.

This command is invaluable for system administrators and network engineers who need to diagnose performance bottlenecks or monitor the usage of network file shares accessed via the CIFS protocol. By observing the I/O patterns, users can identify if a particular CIFS share is experiencing high load or if network performance is impacting file operations.

cifsiostat relies on the kernel's ability to expose CIFS statistics, typically found in /proc/fs/cifs/Stats or similar kernel interfaces. Its functionality is dependent on the CIFS module being loaded and actively used for mounted shares. If no CIFS shares are mounted or the kernel does not expose the necessary statistics, the command may report no data or an error. It provides statistics only for CIFS mounts, not for other network file systems like NFS, or local disk I/O.

cifsiostat gathers its data directly from the Linux kernel's CIFS module statistics. These statistics include information on read/write operations, bytes transferred, and average request sizes, providing a granular view of I/O performance on CIFS mounted shares.

By default, cifsiostat reports throughput in bytes per second. Users can easily switch to more readable units like kilobytes per second (-k) or megabytes per second (-m) for easier interpretation of high-volume data transfers.

cifsiostat is part of the long-standing sysstat project, a comprehensive collection of performance monitoring tools for Linux. The sysstat package (which includes tools like iostat, sar, mpstat, etc.) has been continuously developed since the early 2000s, providing essential insights into system resource utilization. cifsiostat was specifically added to address the growing need for dedicated monitoring of CIFS/SMB network file system performance, reflecting the widespread adoption of Windows-compatible file sharing in Linux environments.

iostat(1), sar(1), mpstat(1), mount.cifs(8), smbstatus(8)