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Merge lp:~serge-hallyn/ubuntu/precise/ubuntu-core-doc/serverguide-ppetrakis into lp:~peter-petrakis/ubuntu/precise/ubuntu-core-doc/serverguide

  1. Precise (12.04)
  2. serverguide-ppetrakis
  3. Merge into serverguide
Proposed by Peter Petrakis
Status: Merged
Approved by: Peter Petrakis
Approved revision: 70
Merged at revision: 72
Proposed branch: lp:~serge-hallyn/ubuntu/precise/ubuntu-core-doc/serverguide-ppetrakis
Merge into: lp:~peter-petrakis/ubuntu/precise/ubuntu-core-doc/serverguide
Diff against target: 151 lines (+33/-23)
3 files modified
serverguide/C/storage/dm-multipath/dm-multipath.xml (+25/-14)
serverguide/C/storage/dm-multipath/multipath-components-table.xml (+3/-4)
serverguide/C/storage/dm-multipath/multipath-config-defaults-table.xml (+5/-5)
To merge this branch: bzr merge lp:~serge-hallyn/ubuntu/precise/ubuntu-core-doc/serverguide-ppetrakis
Reviewer Review Type Date Requested Status
Peter Petrakis Approve
Review via email: mp+98488@code.launchpad.net
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Peter Petrakis (peter-petrakis) wrote :

Taking entire comment, will remove comment concerning config file blacklist in subsequent commit.

review: Approve

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=== modified file 'serverguide/C/storage/dm-multipath/dm-multipath.xml'
--- serverguide/C/storage/dm-multipath/dm-multipath.xml 2012-03-16 14:34:18 +0000
+++ serverguide/C/storage/dm-multipath/dm-multipath.xml 2012-03-20 19:12:21 +0000
@@ -57,7 +57,7 @@
57 prio alua57 prio alua
58}</screen></para>58}</screen></para>
5959
60 <para>See Table, <link60 <para>See Table <link
61 linkend="priority-checker-conversion-table">"Priority Checker61 linkend="priority-checker-conversion-table">"Priority Checker
62 Conversion"</link> for a complete listing</para>62 Conversion"</link> for a complete listing</para>
6363
@@ -134,15 +134,25 @@
134 <sect2 id="multipath-overview">134 <sect2 id="multipath-overview">
135 <title>Overview</title>135 <title>Overview</title>
136136
137 <para>DM-Multipath can be used to provide: Redundancy DM-Multipath can137 <para>DM-Multipath can be used to provide:</para>
138
139 <itemizedlist>
140 <listitem><para><emphasis> Redundancy </emphasis>
141 DM-Multipath can
138 provide failover in an active/passive configuration. In an142 provide failover in an active/passive configuration. In an
139 active/passive configuration, only half the paths are used at any time143 active/passive configuration, only half the paths are used at any time
140 for I/O. If any element of an I/O path (the cable, switch, or144 for I/O. If any element of an I/O path (the cable, switch, or
141 controller) fails, DM-Multipath switches to an alternate path. Improved145 controller) fails, DM-Multipath switches to an alternate path.
146 </para>
147 </listitem>
148
149 <listitem><para><emphasis> Improved Performance </emphasis>
142 Performance DM-Multipath can be configured in active/active mode, where150 Performance DM-Multipath can be configured in active/active mode, where
143 I/O is spread over the paths in a round-robin fashion. In some151 I/O is spread over the paths in a round-robin fashion. In some
144 configurations, DM-Multipath can detect loading on the I/O paths and152 configurations, DM-Multipath can detect loading on the I/O paths and
145 dynamically re-balance the load.</para>153 dynamically re-balance the load.</para>
154 </listitem>
155 </itemizedlist>
146 </sect2>156 </sect2>
147157
148 <sect2 id="multipath-storage-array-support">158 <sect2 id="multipath-storage-array-support">
@@ -163,8 +173,8 @@
163 <sect2 id="multipath-dm-multipath-components">173 <sect2 id="multipath-dm-multipath-components">
164 <title>&DMM; components</title>174 <title>&DMM; components</title>
165175
166 <para>Table, “<link linkend="multipath-components-table">DM-Multipath176 <para>Table “<link linkend="multipath-components-table">DM-Multipath
167 Components”</link>. describes the components of DM-Multipath.177 Components”</link> describes the components of the DM-Multipath package.
168 <xi:include href="multipath-components-table.xml"178 <xi:include href="multipath-components-table.xml"
169 xmlns:xi="http://www.w3.org/2001/XInclude"/></para>179 xmlns:xi="http://www.w3.org/2001/XInclude"/></para>
170 </sect2>180 </sect2>
@@ -226,9 +236,10 @@
226 a multipath device is set to its WWID. Alternately, you can set the236 a multipath device is set to its WWID. Alternately, you can set the
227 <emphasis role="bold"><link237 <emphasis role="bold"><link
228 linkend="attribute-user_friendly_names">user_friendly_names</link>238 linkend="attribute-user_friendly_names">user_friendly_names</link>
229 </emphasis>option in the multipath configuration file, which sets the239 </emphasis>option in the multipath configuration file,
230 alias to a node-unique name of the form <emphasis240 which causes DM-Multipath to use a node-unique alias of the form
231 role="bold">mpathn</emphasis>. For example, a node with two HBAs241 <emphasis role="bold">mpathn</emphasis> as the name.
242 For example, a node with two HBAs
232 attached to a storage controller with two ports via a single unzoned FC243 attached to a storage controller with two ports via a single unzoned FC
233 switch sees four devices: <emphasis role="bold">/dev/sda</emphasis>,244 switch sees four devices: <emphasis role="bold">/dev/sda</emphasis>,
234 <emphasis role="bold">/dev/sdb</emphasis>, <emphasis245 <emphasis role="bold">/dev/sdb</emphasis>, <emphasis
@@ -286,9 +297,9 @@
286 nodes in the cluster. This should not cause any difficulties if you use297 nodes in the cluster. This should not cause any difficulties if you use
287 LVM to create logical devices from the multipath device, but if you298 LVM to create logical devices from the multipath device, but if you
288 require that your multipath device names be consistent in every node it299 require that your multipath device names be consistent in every node it
289 is recommended that you not set the <emphasis300 is recommended that you leave the <emphasis
290 role="bold">user_friendly_names</emphasis> option to <emphasis301 role="bold">user_friendly_names</emphasis> option set to <emphasis
291 role="bold">yes</emphasis> and that you not configure aliases for the302 role="bold">no</emphasis> and that you not configure aliases for the
292 devices. By default, if you do not set <emphasis303 devices. By default, if you do not set <emphasis
293 role="bold">user_friendly_names</emphasis> to yes or configure an alias304 role="bold">user_friendly_names</emphasis> to yes or configure an alias
294 for a device, a device name will be the WWID for the device, which is305 for a device, a device name will be the WWID for the device, which is
@@ -452,9 +463,9 @@
452 is also required.</para>463 is also required.</para>
453464
454 <para>A basic <emphasis role="bold">/etc/multipath.conf </emphasis>465 <para>A basic <emphasis role="bold">/etc/multipath.conf </emphasis>
455 should consist at the very least a blacklist of devices you wish466 should contain at the very least a blacklist of devices which
456 multipath to leave alone. Some devices don't react well to multipath's467 multipath should leave alone. Some devices don't react well to multipath's
457 probing.<screen id="multipath-skel-config">blacklist {468 probing.[SERGE ASKS: can we have a citation for this?]<screen id="multipath-skel-config">blacklist {
458 devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"469 devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
459 devnode "^hd[a-z]"470 devnode "^hd[a-z]"
460 devnode "^dcssblk[0-9]*"471 devnode "^dcssblk[0-9]*"
461472
=== modified file 'serverguide/C/storage/dm-multipath/multipath-components-table.xml'
--- serverguide/C/storage/dm-multipath/multipath-components-table.xml 2012-03-16 14:04:19 +0000
+++ serverguide/C/storage/dm-multipath/multipath-components-table.xml 2012-03-20 19:12:21 +0000
@@ -33,7 +33,7 @@
33 </entry>33 </entry>
3434
35 <entry>Lists and configures <emphasis role="bold">multipath</emphasis>35 <entry>Lists and configures <emphasis role="bold">multipath</emphasis>
36 devices. Normally started up with /etc/rc.sysinit, it can also be36 devices. Normally started up with <filename>/etc/rc.sysinit</filename>, it can also be
37 started up by a udev program whenever a block device is added or it37 started up by a udev program whenever a block device is added or it
38 can be run by the initramfs file system.</entry>38 can be run by the initramfs file system.</entry>
39 </row>39 </row>
@@ -45,9 +45,8 @@
4545
46 <entry>Monitors paths; as paths fail and come back, it may initiate46 <entry>Monitors paths; as paths fail and come back, it may initiate
47 path group switches. Provides for interactive changes to <emphasis47 path group switches. Provides for interactive changes to <emphasis
48 role="bold">multipath</emphasis> devices. This must be restarted for48 role="bold">multipath</emphasis> devices. This daemon must be restarted for
49 any changes to the <emphasis49 any changes to the <filename>/etc/multipath.conf</filename> file to take effect.</entry>
50 role="bold">/etc/multipath.conf</emphasis> file.</entry>
51 </row>50 </row>
5251
53 <row>52 <row>
5453
=== modified file 'serverguide/C/storage/dm-multipath/multipath-config-defaults-table.xml'
--- serverguide/C/storage/dm-multipath/multipath-config-defaults-table.xml 2012-03-16 14:34:18 +0000
+++ serverguide/C/storage/dm-multipath/multipath-config-defaults-table.xml 2012-03-20 19:12:21 +0000
@@ -366,8 +366,8 @@
366 <emphasis role="bold">user_friendly_names</emphasis>366 <emphasis role="bold">user_friendly_names</emphasis>
367 </entry>367 </entry>
368368
369 <entry>If set to yes, specifies that the system should use the /etc/369 <entry>If set to yes, specifies that the system should use the
370 <emphasis role="bold">multipath</emphasis>/bindings file to assign a370 <filename>/etc/multipath/bindings</filename> file to assign a
371 persistent and unique <emphasis role="bold">alias</emphasis> to the371 persistent and unique <emphasis role="bold">alias</emphasis> to the
372 <emphasis role="bold">multipath</emphasis>, in the form of mpathn. If372 <emphasis role="bold">multipath</emphasis>, in the form of mpathn. If
373 set to no, specifies that the system should use the WWID as the373 set to no, specifies that the system should use the WWID as the
@@ -409,7 +409,7 @@
409 opened by <emphasis role="bold">multipath</emphasis> and the <emphasis409 opened by <emphasis role="bold">multipath</emphasis> and the <emphasis
410 role="bold">multipathd</emphasis> daemon. This is equivalent to the410 role="bold">multipathd</emphasis> daemon. This is equivalent to the
411 ulimit -n command. A value of max will set this to the system limit411 ulimit -n command. A value of max will set this to the system limit
412 from /proc/sys/fs/nr_open. If this is not set, the maximum number of412 from <filename>/proc/sys/fs/nr_open</filename>. If this is not set, the maximum number of
413 open file descriptors is taken from the calling process; it is usually413 open file descriptors is taken from the calling process; it is usually
414 1024. To be safe, this should be set to the maximum number of paths414 1024. To be safe, this should be set to the maximum number of paths
415 plus 32, if that number is greater than 1024.</entry>415 plus 32, if that number is greater than 1024.</entry>
@@ -422,8 +422,8 @@
422422
423 <entry>The timeout to use for path checkers that issue SCSI commands423 <entry>The timeout to use for path checkers that issue SCSI commands
424 with an explicit timeout, in seconds. <para>The default value is taken424 with an explicit timeout, in seconds. <para>The default value is taken
425 from sys/block/sdx/device/timeout, which is425 from </filename>/sys/block/sdx/device/timeout</filename>, which is
426 <literal>30</literal>seconds as of 12.04 LTS</para></entry>426 <literal>30</literal> seconds as of 12.04 LTS</para></entry>
427 </row>427 </row>
428428
429 <row>429 <row>

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