NAME¶

biopattern - Identify random/sequential disk access patterns.

SYNOPSIS¶

biopattern [-h] [-d DISK] [interval] [count]

DESCRIPTION¶

This traces block device I/O (disk I/O), and prints ratio of random/sequential I/O for each disk or the specified disk either on Ctrl-C, or after a given interval in seconds.

This works by tracing kernel tracepoint block:block_rq_complete.

Since this uses BPF, only the root user can use this tool.

REQUIREMENTS¶

CONFIG_BPF and bcc.

OPTIONS¶

-h

Show help message and exit.

-d

Trace this disk only.

interval

Print output every interval seconds, if any.

count

Number of interval summaries.

EXAMPLES¶

Trace access patterns of all disks, and print a summary on Ctrl-C:

# biopattern

Trace disk sdb only:

# biopattern -d sdb

Print 1 second summaries, 10 times:

# biopattern 1 10

FIELDS¶

TIME

Time of the output, in HH:MM:SS format.

DISK

Disk device name.

%RND

Ratio of random I/O.

%SEQ

Ratio of sequential I/O.

COUNT

Number of I/O during the interval.

KBYTES

Total Kbytes for these I/O, during the interval.

OVERHEAD¶

Since block device I/O usually has a relatively low frequency (< 10,000/s), the overhead for this tool is expected to be low or negligible. For high IOPS storage systems, test and quantify before use.

SOURCE¶

This is from bcc.

https://github.com/iovisor/bcc

Also look in the bcc distribution for a companion _examples.txt file containing example usage, output, and commentary for this tool.

OS¶

Linux

AUTHOR¶

Rocky Xing

SEE ALSO¶

biosnoop(8), biolatency(8), iostat(1)