From: Peter Palfrader <peter@palfrader.org>
Date: Mon, 18 Jun 2012 11:12:17 +0000 (+0200)
Subject: shell magic
X-Git-Url: https://git.adam-barratt.org.uk/?p=mirror%2Fdsa-wiki.git;a=commitdiff_plain;h=b1c2f86669262e2df112d1b9016339cad192d15e

shell magic
---

diff --git a/input/howto/export-iscsi.creole b/input/howto/export-iscsi.creole
index 54ce165..ce89ce8 100644
--- a/input/howto/export-iscsi.creole
+++ b/input/howto/export-iscsi.creole
@@ -37,4 +37,64 @@ This document describes how to add new new volumes on gustini and add them into
 * map the new volume to traetta.debian.org, LUN 12
   + map volume berlioz-boot lun 12 host traetta access rw
   (again, there is a 'help map volume' command with lots of informations)
+
+* Run 'show host-maps $host' again, then, on the host, run:
+	convert_sn() {
+	  local sn a b c d
+	  sn="$1"
+	  a="${sn%??????????????????????????}"; sn="${sn#??????}"
+	  b="${sn%????????????????????}"; sn="${sn#??????}"
+	  c="${sn%??????????????}"; sn="${sn#??????}"
+	  d="$sn"
+
+	  if [ "${c#0000}" = "$c" ]; then
+	    echo >&2 "sn has unexpected value ($1: $a - $b - $c - $d)"
+	    return 1
+	  fi
+
+	  echo "36${a}000${b}${c#0000}${d}"
+	  return 0
+	}
+
+	parse_volume() {
+	  host=`hostname`
+	  echo "Paste appropriate 'show host-maps $host' output line:"
+	  read name sn id lun access channels
+
+	  if [ "$access" != "rw" ]; then
+	    echo >&2 "Do not have rw access"
+	    return 1
+	  fi
+
+	  if [ "$(echo -n "$sn" | wc -c)" != "32" ]; then
+	    echo >&2 "Unexpected sn length in '$sn' (wanted 32 chars)"
+	    return 1
+	  fi
+
+	  wwid=$(convert_sn "$sn")
+
+	  if [ -z "$wwid" ]; then
+	    return 1
+	  fi
+
+	  echo ""
+	  echo "  multipath {"
+	  echo "    wwid $wwid"
+	  echo "    alias $name"
+	  echo "  }"
+	  echo ""
+
+	  mp="$(multipath -ll $wwid)"
+	  if [ -z "$mp" ]; then
+	    echo >&2 "Warning: multipath does not know about $wwid"
+	    return 1
+	  fi
+
+	  if ! echo "$mp" | grep -q ":$lun "; then
+	    echo >&2 "Warning: Are you sure $wwid is lun $lun?  multipath -ll disagrees"
+	    return 1
+	  fi
+	}
+
+	parse_volume
 }}}