<para> <literal>changelog_register</literal></para>
</entry>
<entry>
- <para> Registers a new changelog user for a particular device. Changelog entries are not purged beyond a registered user's set point (see <literal>lfs changelog_clear</literal>).</para>
+ <para> Registers a new changelog user for a particular device.
+ Changelog entries are saved persistently on the MDT with each
+ filesystem operation, and are only purged beyond all registered
+ user's minimum set point (see
+ <literal>lfs changelog_clear</literal>). This may cause the
+ Changelog to consume a large amount of space, eventually
+ filling the MDT, if a changelog user is registered but never
+ consumes those records.</para>
</entry>
</row>
<row>
<para>changelog_deregister <replaceable>id</replaceable></para>
</entry>
<entry>
- <para> Unregisters an existing changelog user. If the user's "clear" record number is the minimum for the device, changelog records are purged until the next minimum.</para>
+ <para> Unregisters an existing changelog user. If the
+ user's "clear" record number is the minimum for
+ the device, changelog records are purged until the next minimum.
+ </para>
</entry>
</row>
</tbody>
<title>Files</title>
<para>The llstat files are located at:</para>
<screen>/proc/fs/lustre/mdt/MDS/*/stats
-/proc/fs/lustre/mds/*/exports/*/stats
+/proc/fs/lustre/mdt/*/exports/*/stats
/proc/fs/lustre/mdc/*/stats
/proc/fs/lustre/ldlm/services/*/stats
/proc/fs/lustre/ldlm/namespaces/*/pool/stats
<para> Per-client statistics tracked on the servers</para>
</listitem>
</itemizedlist>
- <para>Each MDT and OST now tracks LDLM and operations statistics for every connected client, for comparisons and simpler collection of distributed job statistics.</para>
+ <para>Each MDS and OSS now tracks LDLM and operations statistics for
+ every connected client, for comparisons and simpler collection of
+ distributed job statistics.</para>
<screen>/proc/fs/lustre/mds|obdfilter/*/exports/
</screen>
<itemizedlist>
<para> Improved MDT statistics</para>
</listitem>
</itemizedlist>
- <para>More detailed MDT operations statistics are collected for better profiling.</para>
- <screen>/proc/fs/lustre/mds/*/stats
+ <para>More detailed MDT operations statistics are collected for better
+ profiling.</para>
+ <screen>/proc/fs/lustre/mdt/*/md_stats
</screen>
</section>
<section remap="h3">
Testing / Debugging Utilities</title>
<para>Lustre offers the following test and debugging utilities.</para>
<section remap="h5">
- <title><indexterm><primary>loadgen</primary></indexterm>
-loadgen</title>
- <para>The Load Generator (loadgen) is a test program designed to simulate large numbers of Lustre clients connecting and writing to an OST. The loadgen utility is located at lustre/utils/loadgen (in a build directory) or at /usr/sbin/loadgen (from an RPM).</para>
- <para>Loadgen offers the ability to run this test:</para>
- <orderedlist>
- <listitem>
- <para>Start an arbitrary number of (echo) clients.</para>
- </listitem>
- <listitem>
- <para>Start and connect to an echo server, instead of a real OST.</para>
- </listitem>
- <listitem>
- <para>Create/bulk_write/delete objects on any number of echo clients simultaneously.</para>
- </listitem>
- </orderedlist>
- <para>Currently, the maximum number of clients is limited by MAX_OBD_DEVICES and the amount of memory available.</para>
- </section>
- <section remap="h5">
- <title>Usage</title>
- <para>The loadgen utility can be run locally on the OST server machine or remotely from any LNET host. The device command can take an optional NID as a parameter; if unspecified, the first local NID found is used.</para>
- <para>The obdecho module must be loaded by hand before running loadgen.</para>
- <screen># cd lustre/utils/
-# insmod ../obdecho/obdecho.ko
-# ./loadgen
-loadgen> h
-This is a test program used to simulate large numbers of clients. The echo \
-obds are used, so the obdecho module must be loaded.
-
-Typical usage would be:
-loadgen> dev lustre-OST0000 set the target device
-loadgen> start 20 start 20 echo clients
-loadgen> wr 10 5 have 10 clients do simultaneous brw_write \
-tests 5 times each
-
-Available commands are:
- device
- dl
- echosrv
- start
- verbose
- wait
- write
- help
- exit
- quit
-
-For more help type: help command-name
-loadgen>
-loadgen> device lustre-OST0000 192.168.0.21@tcp
-Added uuid OSS_UUID: 192.168.0.21@tcp
-Target OST name is 'lustre-OST0000'
-loadgen>
-loadgen> st 4
-start 0 to 4
-./loadgen: running thread #1
-./loadgen: running thread #2
-./loadgen: running thread #3
-./loadgen: running thread #4
-loadgen> wr 4 5
-Estimate 76 clients before we run out of grant space (155872K / 2097152)
-1: i0
-2: i0
-4: i0
-3: i0
-1: done (0)
-2: done (0)
-4: done (0)
-3: done (0)
-wrote 25MB in 1.419s (17.623 MB/s)
-loadgen>
-</screen>
- <para>The loadgen utility prints periodic status messages; message output can be controlled with the verbose command.</para>
- <para>To insure that a file can be written to (a requirement of write cache), OSTs reserve ("grants"), chunks of space for each newly-created file. A grant may cause an OST to report that it is out of space, even though there is plenty of space on the disk, because the space is "reserved" by other files. The loadgen utility estimates the number of simultaneous open files as the disk size divided by the grant size and reports that number when the write tests are first started.</para>
- <para>Echo Server</para>
- <para>The loadgen utility can start an echo server. On another node, loadgen can specify the echo server as the device, thus creating a network-only test environment.</para>
- <screen>loadgen> echosrv
-loadgen> dl
- 0 UP obdecho echosrv echosrv 3
- 1 UP ost OSS OSS 3
-</screen>
- <para>On another node:</para>
- <screen>loadgen> device echosrv cfs21@tcp
-Added uuid OSS_UUID: 192.168.0.21@tcp
-Target OST name is 'echosrv'
-loadgen> st 1
-start 0 to 1
-./loadgen: running thread #1
-loadgen> wr 1
-start a test_brw write test on X clients for Y iterations
-usage: write <num_clients> <num_iter> [<delay>]
-loadgen> wr 1 1
-loadgen>
-1: i0
-1: done (0)
-wrote 1MB in 0.029s (34.023 MB/s)
-</screen>
- <para>Scripting</para>
- <para>The threads all perform their actions in non-blocking mode; use the wait command to block for the idle state. For example:</para>
- <screen>#!/bin/bash
-./loadgen << EOF
-device lustre-OST0000
-st 1
-wr 1 10
-wait
-quit
-EOF
-</screen>
- </section>
- <section remap="h5">
<title><indexterm><primary>lr_reader</primary></indexterm>
lr_reader</title>
<para>The lr_reader utility translates the content of the <literal>last_rcvd</literal> and <literal>reply_data</literal> files into human-readable form.</para>
git://git.whamcloud.com / doc / manual.git / blobdiff