nvme-cli/Documentation/nvme-get-log.1

'\" t
.\"     Title: nvme-get-log
.\"    Author: [FIXME: author] [see http://www.docbook.org/tdg5/en/html/author]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 10/31/2024
.\"    Manual: NVMe Manual
.\"    Source: NVMe
.\"  Language: English
.\"
.TH "NVME\-GET\-LOG" "1" "10/31/2024" "NVMe" "NVMe Manual"
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.SH "NAME"
nvme-get-log \- Retrieves a log page from an NVMe device
.SH "SYNOPSIS"
.sp
.nf
\fInvme get\-log\fR <device> [\-\-log\-id=<log\-id> | \-i <log\-id>]
                        [\-\-log\-len=<log\-len> | \-l <log\-len>]
                        [\-\-aen=<aen> | \-a <aen>]
                        [\-\-namespace\-id=<nsid> | \-n <nsid>]
                        [\-\-raw\-binary | \-b]
                        [\-\-lpo=<offset> | \-L <offset>]
                        [\-\-lsp=<field> | \-s <field>]
                        [\-\-lsi=<field> | \-S <field>]
                        [\-\-rae | \-r]
                        [\-\-csi=<command_set_identifier> | \-y <command_set_identifier>]
                        [\-\-ot=<offset_type> | \-O <offset_type>]
                        [\-\-xfer\-len=<length> | \-x <length>]
                        [\-\-output\-format=<fmt> | \-o <fmt>] [\-\-verbose | \-v]
.fi
.SH "DESCRIPTION"
.sp
Retrieves an arbitrary NVMe log page from an NVMe device and provides the returned structure\&.
.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
On success, the returned log structure may be returned in one of several ways depending on the option flags; the structure may be displayed in hex by the program or the raw buffer may be printed to stdout for another program to parse\&.
.SH "OPTIONS"
.PP
\-l <log\-len>, \-\-log\-len=<log\-len>
.RS 4
Allocates a buffer of <log\-len> bytes size and requests this many bytes be returned in the constructed NVMe command\&. This param is mandatory\&.
.RE
.PP
\-i <log\-id>, \-\-log\-id=<log\-id>
.RS 4
Sets the commands requested log\-id to <log\-id>\&. Defaults to 0\&.
.RE
.PP
\-a <aen>, \-\-aen=<aen>
.RS 4
Convenience field for extracting log information based on an asynchronous event notification result\&. This will override log\-id and log\-len, if set\&.
.RE
.PP
\-n <nsid>, \-\-namespace\-id=<nsid>
.RS 4
Sets the command\(cqs nsid value to the given nsid\&. Defaults to 0xffffffff if not given\&. This option may not affect anything depending on the log page, which may or may not be specific to a namespace\&.
.RE
.PP
\-b, \-\-raw\-binary
.RS 4
Print the raw log buffer to stdout\&.
.RE
.PP
\-L <offset>, \-\-lpo=<offset>
.RS 4
The log page offset specifies the location within a log page to start returning data from\&. It\(cqs Dword\-aligned and 64\-bits\&.
.RE
.PP
\-s <field>, \-\-lsp=<field>
.RS 4
The log specified field of LID\&.
.RE
.PP
\-S <field>, \-\-lsi=<field>
.RS 4
The log specified field of Log Specific Identifier\&.
.RE
.PP
\-r, \-\-rae
.RS 4
Retain an Asynchronous Event\&.
.RE
.PP
\-y <command_set_identifier>, \-\-csi=<command_set_identifier>
.RS 4
This field specifies the identifier of command set\&. if not issued, NVM Command Set will be selected\&.
.RE
.PP
\-O, \-\-ot
.RS 4
This field specifies the offset type\&. If set to false, the Log Page Offset Lower field and the Log Page Offset Upper field specify the byte offset into the log page to be returned\&. If set to true, the Log Page Offset Lower field and the Log Page Offset Upper field specify the index into the list of data structures in the log page to be returned\&. The default is byte offset\&. If the option is specified the index mode is used\&.
.RE
.PP
\-x <length>
.RS 4
\-\-xfer\-len <length>: Specify the read chunk size\&. The length argument is expected to be a multiple of 4096\&. The default size is 4096\&.
.RE
.PP
\-o <fmt>, \-\-output\-format=<fmt>
.RS 4
Set the reporting format to
\fInormal\fR,
\fIjson\fR
or
\fIbinary\fR\&. Only one output format can be used at a time\&.
.RE
.PP
\-v, \-\-verbose
.RS 4
Increase the information detail in the output\&.
.RE
.SH "EXAMPLES"
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Get 512 bytes from log page 2
.sp
.if n \{\
.RS 4
.\}
.nf
# nvme get\-log /dev/nvme0 \-\-log\-id=2 \-\-log\-len=512
.fi
.if n \{\
.RE
.\}
.sp
The above example will get log page 2 (SMART), and request 512 bytes\&. On success, the returned log will be dumped in hex and not interpreted by the program\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Have the program return the raw log page in binary:
.sp
.if n \{\
.RS 4
.\}
.nf
# nvme get\-log /dev/nvme0 \-log\-id=2 \-\-log\-len=512 \-\-raw\-binary > log_page_2\&.raw
# nvme get\-log /dev/nvme0 \-i 2 \-l 512 \-b > log_page_2\&.raw
.fi
.if n \{\
.RE
.\}
.sp
It is not a good idea to not redirect stdout when using this mode\&.
.RE
.SH "NVME"
.sp
Part of the nvme\-user suite