`fsysinfo`

Display filesystem statistics (QNX)

Syntax:

fsysinfo [-b] [-d secs] [-r] [file]

Options:

-b: Base the counts from the time fsysinfo starts (useful only with -d)
-d secs: Update the fullscreen display every secs seconds. To exit the display, you press Ctrl-C.
-r: Reset Fsys's internal counters. To use this option, you must be logged in as root.
file: Display statistics for the filesystem containing this file (default is the filesystem which contains the current working directory).

Description:

The fsysinfo utility displays statistical information obtained from the Filesystem Manager (Fsys). The utility displays this information in three sections:

configurable limits
cache-and-disk statistics
critical-function statistics

The fsysinfo utility displays this information only once unless you specify -d.

Because Fsys doesn't proportion its cache according to partitions, disks, or drivers, the statistics you see represent the total usage of the Fsys responsible for the named path (i.e. the statistics don't reflect usage for just that path).

If you specify the -b option, the statistics shown in the cache-and-disk and critical-function sections show activity from the time fsysinfo started. Otherwise, they show activity from when Fsys started or from when you reset Fsys's counters with fsysinfo -r.

Configurable limits

The configurable limits section shows information for the following configurable Fsys resource limits:

Resource	`Fsys` option for configuring limit
inodes	`-i`
names	`-C`
file descriptions (open control blocks)	`-f`
locks	`-l` ("el")
threads	`-t`

For each of these configurable limits, the display shows the:

current value
greatest value that has been used at one time
limit set by Fsys

If your machine is tight on memory you can use this information to tune your Fsys limits. You should find the default values generous for most systems.

Cache-and-disk statistics

The cache-and-disk statistics can help you tune the cache size to obtain the best performance. Generally, the higher you raise the cache hit ratio (displayed as a percentage on the first line of these statistics), the better the performance.

This statistic:	Represents the number of:
data hits	times `Fsys` had to read a block and found that block already in cache. A cache hit may occur when a program does a read or readdir.
data delays	times a driver started reading a requested data block that wasn't yet available (`Fsys` performs a pre-read when it recognizes that the file usage pattern is sequential). If `Fsys` pre-reads a single block, any subsequent blocks for the read request that reside in cache are also considered delayed and are added to this number.
data misses	times the requested data block wasn't in cache, and `Fsys` had to start a disk read.
metadata hits	times `Fsys` had to read a block in the process of obtaining metadata (data about the file required to open, stat, get extent information and so on) and found that block already in cache.
metadata misses	times the requested block block of metadata wasn't in cache, and `Fsys` had to start a disk read.
cache lookups	reads, writes, and other internal functions that have been performed by `Fsys` (does not represent the sum of hits, delays, and misses).
cache writes	cache blocks that have been queued for writing to disk. Because of write buffering, a block may be queued many times before hitting the disk.
disk reads	block read requests `Fsys` has made to its drivers.
disk writes	block write requests `Fsys` has made to its drivers.

Critical-function statistics

These statistics represent how often certain functions in Fsys have been called. You can't use this information for tuning purposes, but it does give an idea of how busy the system is.

With the exception of namei(), which is the internal function used to map a pathname to an in-memory inode, all the critical function names have a one-to-one correspondence with library functions of the same name.

When you run fsysinfo in fullscreen display mode (-d), the critical-functions section displays:

the number of times each function was called
a per-second count of the number of calls since the last display
the average number of calls per second since the Fsys counters were initialized (or since fsysinfo was started if started with -b)

When you don't run fsysinfo in fullscreen mode, it displays only the number of times each function was called and the average number of calls per second.

Examples:

Display statistics for the current directory:

    fsysinfo

Reset the stat counters in the Fsys process that's responsible for /tmp:

    fsysinfo -r /tmp

Update the statistical display every three seconds, showing Fsys statistics for /:

    fsysinfo -d3 /

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