'\" t
.\"     Title: nvme-feat-num-queues
.\"    Author: [FIXME: author] [see http://www.docbook.org/tdg5/en/html/author]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 10/30/2026
.\"    Manual: NVMe Manual
.\"    Source: NVMe
.\"  Language: English
.\"
.TH "NVME\-FEAT\-NUM\-QUE" "1" "10/30/2026" "NVMe" "NVMe Manual"
.\" -----------------------------------------------------------------
.\" * Define some portability stuff
.\" -----------------------------------------------------------------
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" http://bugs.debian.org/507673
.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\" -----------------------------------------------------------------
.\" * set default formatting
.\" -----------------------------------------------------------------
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.\" -----------------------------------------------------------------
.\" * MAIN CONTENT STARTS HERE *
.\" -----------------------------------------------------------------
.SH "NAME"
nvme-feat-num-queues \- Get and set number of queues feature
.SH "SYNOPSIS"
.sp
.nf
\fInvme\fR [<global\-options>] \fIfeat num\-queues\fR <device>
                        [\-\-nsqr=<nsqr> | \-n <nsqr>]
                        [\-\-ncqr=<ncqr> | \-c <ncqr>]
                        [\-\-sel=<select> | \-S <select>] [\-\-save | \-s]
.fi
.SH "DESCRIPTION"
.sp
Get and set the number of queues feature\&.
.sp
The <device> parameter is mandatory and may be either the NVMe character device (ex: /dev/nvme0), or a namespace block device (ex: /dev/nvme0n1)\&.
.sp
If any of the setting options (\-\-nsqr or \-\-ncqr) are specified, the command will update the requested number of queues\&. If an option is omitted during a set operation, the command will first retrieve the current values and retain them\&. If neither option is specified, it will simply retrieve and display the current configuration\&.
.sp
On success it returns 0, error code otherwise\&.
.SH "OPTIONS"
.PP
\-n <nsqr>, \-\-nsqr=<nsqr>
.RS 4
Number of I/O submission queues requested\&.
.RE
.PP
\-c <ncqr>, \-\-ncqr=<ncqr>
.RS 4
Number of I/O completion queues requested\&.
.RE
.PP
\-S <select>, \-\-sel=<select>
.RS 4
Select (SEL): This field specifies which value of the attributes to return in the provided data:
.TS
allbox tab(:);
lt lt lt
lt lt lt
lt lt lt
lt lt lt
lt lt lt.
T{
Select
T}:T{
Name
T}:T{
Description
T}
T{
0
T}:T{
current
T}:T{
Current
T}
T{
1
T}:T{
default
T}:T{
Default
T}
T{
2
T}:T{
saved
T}:T{
Saved
T}
T{
3
T}:T{
supported
T}:T{
Supported capabilities
T}
.TE
.sp 1
.RE
.PP
\-s, \-\-save
.RS 4
Save the attribute so that it persists through all power states and resets\&.
.RE
.SH "GLOBAL OPTIONS"
.sp
The following options are defined at the top\-level nvme command and are available to this subcommand:
.PP
\-\-dry\-run
.RS 4
Print the command that would be executed, but do not actually execute it\&.
.RE
.PP
\-\-no\-ioctl\-probing
.RS 4
Disable probing for 64\-bit IOCTL support\&.
.RE
.PP
\-\-no\-retries
.RS 4
Disable retry logic on transient errors\&.
.RE
.PP
\-o <fmt>, \-\-output\-format=<fmt>
.RS 4
Set the reporting format to
\fInormal\fR,
\fItabular, \*(Aqjson\fR, or
\fIbinary\fR\&. Only one output format may be used at a time\&.
.RE
.PP
\-\-output\-format\-version=<version>
.RS 4
Select the output format version\&. Version
\fI1\fR
uses the original field naming, while version
\fI2\fR
(default) provides more consistent and script\-friendly field names\&. Other versions are rejected\&.
.RE
.PP
\-\-quiet
.RS 4
Suppress informational messages\&. Errors are still reported, and \-\-quiet cancels any \-\-verbose for the library log level\&.
.RE
.PP
\-\-set\-options=<key=value>[,<key=value>\&...]
.RS 4
Set libnvme library options for this invocation\&. Supported keys are
\fIforce\-4k\fR,
\fImi\-probe\-enabled\fR,
\fItest\-base\-dir\fR
and
\fItest\-sysfs\-dir\fR\&.
.RE
.PP
\-\-timeout=<ms>
.RS 4
Set the timeout for the command in milliseconds\&.
\fIinfinite\fR
or
\fI\-1\fR
waits without a time limit (0xffffffff)\&.
.RE
.PP
\-v, \-\-verbose
.RS 4
Increase the level of detail in the output\&. May be specified multiple times to further increase verbosity\&.
.RE
.sp
These options can also be set as machine\-wide defaults in nvme\-cli\&.conf(5)\&. A command\-line flag always overrides the file\&.
.SH "EXAMPLES"
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Has the program issue a feat num\-queues to get the current configuration:
.sp
.if n \{\
.RS 4
.\}
.nf
# nvme feat num\-queues /dev/nvme0
.fi
.if n \{\
.RE
.\}
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Has the program issue a feat num\-queues to set submission and completion queues:
.sp
.if n \{\
.RS 4
.\}
.nf
# nvme feat num\-queues /dev/nvme0 \-\-nsqr=4 \-\-ncqr=4
.fi
.if n \{\
.RE
.\}
.RE
.SH "NVME"
.sp
Part of the nvme\-user suite\&.