[PATCH] imsm: Add NO_IMSM_PLATFORM flag description to manual.

[PATCH] imsm: Add NO_IMSM_PLATFORM flag description to manual.

[Marcin Tomczak]

In exceptional cases user can use NO_IMSM_PLATFORM flag to use IMSM
metadata RAIDs without valid Intel platform. With this flag set
mdadm does not perform any compatibility checks.

Note: Usage of this flag may lead to data loss!

Signed-off-by: Marcin Tomczak <marcin.tomczak@intel.com>
---
 mdadm.8.in |   19 +++++++++++++++++++
 1 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/mdadm.8.in b/mdadm.8.in
index 535cc39..3ef20c7 100644
--- a/mdadm.8.in
+++ b/mdadm.8.in
@@ -2714,6 +2714,25 @@ to '1', the
 .I mdadm
 will create and devices that are needed.
 
+.TP
+.B IMSM_NO_PLATFORM
+ATTENTION! Usage of this flag is extremely dangerous! You should use
+this flag only when you know what you are doing and when it is
+necessary. Make a backup before any action. You use it on your own
+responsibility - unpredictable effects may appear much later.
+
+The IMSM_NO_PLATFORM flag concerns only IMSM metadata. By default, IMSM
+metadata is supported only by Intel based platforms with OROM and it's
+shared between Linux, Microsoft Windows and OROM, thus you can switch
+between these environments safely. When you use a mdadm command and the
+value of the flag is set to '1', then mdadm does not care about the
+hardware configuration and OROM restrictions. It may cause a
+compatibility problem and OROM or Windows can, for example, set the
+state of the RAID volume to failed and then you may lose all your data.
+Other possible scenario is that created RAID Volume will be
+incompatible with target platform's OROM and volume will not be
+assembled on that platform.
+
 .SH EXAMPLES
 
 .B "  mdadm \-\-query /dev/name-of-device"

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Re: [PATCH] imsm: Add NO_IMSM_PLATFORM flag description to manual.

[NeilBrown]

[-- Attachment #1: Type: text/plain, Size: 2452 bytes --]

On Mon, 18 Feb 2013 12:51:40 +0100 Marcin Tomczak <marcin.tomczak@intel.com>
wrote:

> In exceptional cases user can use NO_IMSM_PLATFORM flag to use IMSM
> metadata RAIDs without valid Intel platform. With this flag set
> mdadm does not perform any compatibility checks.
> 
> Note: Usage of this flag may lead to data loss!
> 
> Signed-off-by: Marcin Tomczak <marcin.tomczak@intel.com>
> ---
>  mdadm.8.in |   19 +++++++++++++++++++
>  1 files changed, 19 insertions(+), 0 deletions(-)
> 
> diff --git a/mdadm.8.in b/mdadm.8.in
> index 535cc39..3ef20c7 100644
> --- a/mdadm.8.in
> +++ b/mdadm.8.in
> @@ -2714,6 +2714,25 @@ to '1', the
>  .I mdadm
>  will create and devices that are needed.
>  
> +.TP
> +.B IMSM_NO_PLATFORM
> +ATTENTION! Usage of this flag is extremely dangerous! You should use
> +this flag only when you know what you are doing and when it is
> +necessary. Make a backup before any action. You use it on your own
> +responsibility - unpredictable effects may appear much later.

I'm sorry, but I'm not going to include that sort of hyperbole in the man
page.  A simple statement of what it does is sufficient.

I have applied this patch.

NeilBrown


From 401f095c39b732b4247bd728cb493eb7bb692298 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Mon, 4 Mar 2013 17:25:36 +1100
Subject: [PATCH] mdadm.8: Detail use for IMSM_NO_PLATFORM environment
 variable.

Suggested-by: Marcin Tomczak <marcin.tomczak@intel.com>

diff --git a/mdadm.8.in b/mdadm.8.in
index a3abc2d..1c06533 100644
--- a/mdadm.8.in
+++ b/mdadm.8.in
@@ -2710,6 +2710,21 @@ to '1', the
 .I mdadm
 will create and devices that are needed.
 
+.TP
+.B IMSM_NO_PLATFORM
+A key value of IMSM metadata is that it allows interoperability with
+boot ROMs on Intel platforms, and with other major operating systems.
+Consequently,
+.I mdadm
+will only allow an IMSM array to be created or modified if detects
+that it is running on an Intel platform which supports IMSM, and
+supports the particular configuration of IMSM that is being requested
+(some functionality requires newer OROM support).
+
+These checks can be suppressed by setting IMSM_NO_PLATFORM=1 in the
+environment.  This can be useful for testing or for disaster
+recovery.  You should be aware that interoperability may be
+compromised by setting this value.
 .SH EXAMPLES
 
 .B "  mdadm \-\-query /dev/name-of-device"


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