'\" t
.\"     Title: ndctl-start-scrub
.\"    Author: [see the "AUTHOR(S)" section]
.\" Generator: Asciidoctor 2.0.12
.\"      Date: 2022-04-08
.\"    Manual: ndctl Manual
.\"    Source: ndctl
.\"  Language: English
.\"
.TH "NDCTL\-START\-SCRUB" "1" "2022-04-08" "ndctl" "ndctl Manual"
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.SH "NAME"
ndctl\-start\-scrub \- start an Address Range Scrub (ARS) operation
.SH "SYNOPSIS"
.sp
.sp
.nf
\fIndctl start\-scrub\fP [<bus\-id> <bus\-id2> ... <bus\-idN>] [<options>]
.fi
.br
.SH "DESCRIPTION"
.sp
NVDIMM Address Range Scrub is a capability provided by platform firmware
that allows for the discovery of memory errors by system software. It
enables system software to pre\-emptively avoid accesses that could lead
to uncorrectable memory error handling events, and it otherwise allows
memory errors to be enumerated.
.sp
The kernel provides a sysfs file (\fIscrub\fP) that when written with the
string "1\(rsn" initiates an ARS operation. The \fIndctl start\-scrub\fP
operation starts an ARS, across all specified buses, and the kernel in
turn proceeds to scrub every persistent memory address region on the
specified buses.
.SH "EXAMPLE"
.sp
Start a scrub on all nvdimm buses in the system. The json listing report
only includes the buses that support ARS operations.
.sp
.if n .RS 4
.nf
.fam C
# ndctl start\-scrub
[
  {
    "provider":"nfit_test.1",
    "dev":"ndbus3",
    "scrub_state":"active"
  },
  {
    "provider":"nfit_test.0",
    "dev":"ndbus2",
    "scrub_state":"active"
  }
]
.fam
.fi
.if n .RE
.sp
When specifying an individual bus, or if there is only one bus in the
system, the command reports whether ARS support is available.
.sp
.if n .RS 4
.nf
.fam C
# ndctl start\-scrub e820
error starting scrub: Operation not supported
.fam
.fi
.if n .RE
.SH "OPTIONS"
.sp
\-v, \-\-verbose
.RS 4
Emit debug messages for the ARS start process
.RE
.SH "COPYRIGHT"
.sp
Copyright \(co 2016 \- 2020, Intel Corporation. License GPLv2: GNU GPL
version 2 \c
.URL "http://gnu.org/licenses/gpl.html" "" "."
This is free software:
you are free to change and redistribute it.  There is NO WARRANTY, to
the extent permitted by law.
.SH "SEE ALSO"
.sp
ndctl\-wait\-scrub(1),
\c
.URL "http://www.uefi.org/sites/default/files/resources/ACPI%206_2_A_Sept29.pdf" "ACPI
6.2 Specification Section 9.20.7.2 Address Range Scrubbing (ARS) Overview"