Bug#808041: s390-zfcp: Install Debian on FC-attached SCSI devices on s390 (patches)

[Philipp Kern]

Hi,

On Tue, Dec 15, 2015 at 03:15:42PM +0100, Hendrik Brueckner wrote:
> Below you can find the patches for the FCP configuration utility.
> The patch set consists of five patches:
> 
> 1. A README file describing how to use the FCP configuration utility.
> 2. Generic interfaces and functions to manage CCW devices on s390.
> 3. Functions to manage FCP devices.
> 4. The FCP configuration utility.
> 5. Debian packaging files to build the Debian Installer udeb.
> 
> Initial tests to configure FCP devices ran successful on z/VM and LPAR
> using FCP devices with and without N_Port ID virtualization (NPIV).
> 
> Review and feedback of the patches is very welcome!  As a beginner in
> Debian packaging, please review the Debian packaging files.

I took the liberty to push the patchset to [1]. This will still require
review, but any potential fix-up commits can just be based on your work.

(I hope to have some more time over the holidays to review, but as said
I can't test it.)

Kind regards and thanks
Philipp Kern

[1] http://anonscm.debian.org/cgit/d-i/s390-zfcp.git


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Bug#808041: s390-zfcp: Install Debian on FC-attached SCSI devices on s390 (patches)

[Hendrik Brueckner]

Control: tags -1 + patch

Below you can find the patches for the FCP configuration utility.
The patch set consists of five patches:

1. A README file describing how to use the FCP configuration utility.
2. Generic interfaces and functions to manage CCW devices on s390.
3. Functions to manage FCP devices.
4. The FCP configuration utility.
5. Debian packaging files to build the Debian Installer udeb.

Initial tests to configure FCP devices ran successful on z/VM and LPAR
using FCP devices with and without N_Port ID virtualization (NPIV).

Review and feedback of the patches is very welcome!  As a beginner in
Debian packaging, please review the Debian packaging files.

Thank you in advance!

Kind regards,
  Hendrik
From b88cc8f54a3badfa1585a7d3d87d0bade3067211 Mon Sep 17 00:00:00 2001
From: Hendrik Brueckner 
Date: Tue, 15 Dec 2015 11:06:21 +0100
Subject: [PATCH 1/5] s390-zfcp: README

Provide a README file with explanations and tipps for using the
FCP device configuration Debian Installer module.

Signed-off-by: Hendrik Brueckner 
---
 README | 118 +
 1 file changed, 118 insertions(+)
 create mode 100644 README

diff --git a/README b/README
new file mode 100644
index 000..7537276
--- /dev/null
+++ b/README
@@ -0,0 +1,118 @@
+= FCP device management for the Debian Installer =
+
+***
+Debian Installer module to configure FCP devices to install Debian
+Linux instances on FC-attached SCSI devices on Linux on z Systems.
+***
+
+Using the FCP device configuration module
+-
+You can use the FCP device configuration module in two different ways:
+
+1. Configuring FCP devices interactively
+2. Configuring FCP devices through preseeding
+
+Configuring FCP devices interactively
+~
+When the FCP device configuration module starts, it scans the
+CCW bus for FCP devices.  If it detects FCP devices, a panel
+appears to let the user select a particular FCP device for
+configuration.
+
+After the user selected a particular FCP device for configuration,
+the module enables the FCP device first.
+
+After the FCP device is active, the module checks if the FCP devices
+uses N_Port ID virtualization.  If the FCP device uses N_Port ID
+virtualization and automatic LUN scanning is switched on (the default
+setting), no further user configuration steps are required.
+The FCP device becomes configured.
+
+If the FCP does not use N_Port ID virtualization or automatic LUN
+scanning is switched off, the user is requested to specify LUNs.
+To add LUNs, the user must specify the target port (WWPN) and the
+logical unit number (LUN) as pair, WWPN:LUN.  The user can add
+numerous LUNs and, if necessary, can also remove them.  The specified
+LUNs will be attached to the system and the FCP device configuration
+module writes the respective configuration file.
+
+Configuring FCP devices through preseeding
+~~
+Use the *s390-zfcp/zfcp* variable to specify one or more FCP devices
+to be configured.  With this variable, you specify a comma-separated
+list of entries.  An entry can be either the bus-ID of an FCP device
+or a combination of the bus-ID of an FCP device followed by the WWPN
+and LUN, each delimited by a colon.
+
+For example:
+
+   0.0.1234,0.0.5678:0x2005000e11159c32:0x1234567800
+
+The bus-ID for an FCP device is sufficient if
+
+1. the FCP device uses N_Port ID virtualization and
+2. automatic LUN scanning is switched on (default)
+
+You have to specify triplets consisting of the bus-ID of the FCP device,
+WWPN, and LUN in any other case.  Note that the FCP device configuration
+module fails if an entry specified with the *s390-zfcp/zfcp* variable is
+not valid.  An error message which describes the error is written to the
+syslog.
+
+
+Additional installation considerations
+~~
+After you completed and configured your FC-attached SCSI devices,
+consider to set up multipath.  To prevent single path failures,
+install your Linux instance on those multipath devices.
+
+Note that it is sufficient to install on multipath devices even
+if there is only a single path available.  Later, you can extend
+your multipath setup and configure additional paths.  Note that
+configuring multipath later, on already installed Linux instances,
+is typically complex.
+
+
+Controlling the FCP device configuration behavior
+-
+You can control different aspects of the FCP device configuration
+through kernel and module parameters.  The FCP device configuration
+module does not change any of the kernel and module parameters
+described below.
+
+scsi_mod.scan
+~
+The