.Dd Oct 9, 2013 .Dt IOSIM 1 .Sh NAME .Nm iosim .Nd A performance tool to simulate I/O workloads. .Sh SYNOPSIS
p .Nm iosim .Ar -c <number> Burst Count. No. of I/Os performed in an I/O burst. Default Value: 10 Valid Range: [0, INT_MAX]
p .Nm iosim .Ar -i <msecs> Inter Burst Duration. Amount of time each thread sleeps between bursts (-1 indicates random durations between 0-100 msecs) Default Value: 0 Valid Range: [-1, INT_MAX]
p .Nm iosim .Ar -d <msecs> Inter I/O delay. Amount of time thread sleeps between issuing I/Os Default Value: 0 Valid Range: [0, INT_MAX]
p .Nm iosim .Ar -t <number> Thread count Default Value: 1 Valid Range: [0, 1000]
p .Nm iosim .Ar -f <number> Workload Type (0/1/2 : Read-Only/Write-Only/Mixed RW) Default Value: 0 Valid Range: [0, 2]
p .Nm iosim .Ar -m <number> I/O Pattern (0/1 : Sequential/Random) Default Value: 0 Valid Range: [0, 1]
p .Nm iosim .Ar -j <bytes> Size of I/O in bytes Default Value: 4096 Valid Range: [0, INT_MAX]
p .Nm iosim .Ar -s <msecs> Frequency of sync() calls Default Value: 5000 Valid Range: [0, INT_MAX]
p .Nm iosim .Ar -l <number> I/O Tier (0/1/2/3) Default Value: 0 Valid Range: [0, 3]
p .Nm iosim .Ar -z <number> Size of the file created specified in pages (Only used when the file is being created by the tool) Default Value: 1 GB Valid Range: [0, INT_MAX]
p .Nm iosim .Ar -x <secs> Test duration (0 indicates that the tool would wait for a Ctrl-C) Default Value: 0 Valid Range: [0, INT_MAX]
p .Nm iosim .Ar -a number I/O Caching behavior (0/1 : Non-cached/Cached) Default Value: 0 Valid Range: [0, 1]
p .Nm iosim .Ar -n <filename> Filename for I/Os (If this option is not specified, the tool would create files on its own) Valid Range: Valid filename .Sh DESCRIPTION The .Nm iosim tool allows simulating workloads for I/O performance evaluation. The tool spawns 'n' threads which issue non-cached I/Os. If specified, it also creates a sync thread which issues system wide sync() calls to flush data and metadata to disk (emulates launchd behavior). The I/Os are issued at the specified I/O tier and the tool reports latency and throughput numbers.
Following is an explanation of the results: Avg. Latency : Avg. latency experienced by the I/Os. Low Latency Histogram: Frequency distribution of I/O latency for low latency I/Os. Latency Histogram: Frequency distribution of I/O latency. Burst Avg. Latency Histogram: Frequency distribution of burst avg. latency. Throughput timeline: Time windowed throughput distrbution..Sh SEE ALSO .Xr fs_usage 1