dmvdostats8

Usage

Overview

dmvdostats displays statistics for VDO (Virtual Data Optimizer) device-mapper targets. It queries each VDO device via the kernel stats message interface and presents the results in either a tabular (report) format or a verbose key-value format.

If no device argument is given, dmvdostats enumerates all device-mapper devices and reports statistics for every VDO target found.

A device argument may name a VDO device directly, or any device-mapper device layered above one (for example an LVM VDO logical volume, or a thin logical volume whose pool data is a VDO). In that case dmvdostats descends the device dependency tree and reports statistics for every underlying VDO device found. As a convenience, a name that does not resolve to any device is retried with the LVM -vpool suffix appended, so the hidden VDO pool device can be named by its pool logical volume name.

dmvdostats is installed as a symlink to dmsetup(8) and may also be invoked as dmsetup vdostats.

Options

-h, --help

Display usage information.

-v, --verbose

Produce verbose output. Instead of the tabular report, display all kernel statistics in a key-value format compatible with the legacy vdostats tool. Derived fields (1K-blocks, used percent, saving percent, write amplification) are inserted into the output.

--count count

Repeat the report count times. Use with --interval to monitor VDO statistics continuously.

--interval seconds

Pause seconds between report iterations when --count is greater than one.

-o, --options fields

Comma-separated list of fields to display. Use -o help to see a list of available fields. If not specified, the default fields are:
vdo_name,vdo_physical_size,vdo_used, vdo_available,vdo_used_pct,vdo_saving_pct.

-O, --sort sort_fields

Comma-separated list of fields to sort by.

-S, --select selection

Display only rows that match the selection criteria. See lvmreport(7) for the selection syntax.

--noheadings

Suppress the headings line in report output.

--nosuffix

Suppress the suffix on size values.

--separator separator

Use separator between fields in report output.

--units units

Set the display unit for size fields. Available units: b(ytes), s(ectors), k(ilobytes), m(egabytes), g(igabytes), t(erabytes), p(etabytes), e(xabytes). Capitalize to use multiples of 1000 (S.I.) instead of 1024. Default is human-readable (h).

Fields

The following fields are available for report output (-o):

Examples

Display default statistics for all VDO devices:

# dmvdostats

Display verbose output for a specific device:

# dmvdostats -v /dev/mapper/vg-vpool0-vpool

Display selected fields:

# dmvdostats -o vdo_name,vdo_used_pct,vdo_saving_pct

Monitor usage every 5 seconds, 10 times:

# dmvdostats --count 10 --interval 5

Filter to devices over 50% usage:

# dmvdostats -S 'vdo_used_pct > 50'