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Forgot to mention, DRBD version is 0.7.11.<br>
<br>
Weilin Gong wrote:
<blockquote cite="mid459EAAC5.2000408@alcatel-lucent.com" type="cite">
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Hi,<br>
<br>
I ran some drbd performance tests with 'tiobench':<br>
<br>
tiobench.pl --identifier drbd-connected --size 5000 --numruns 1 --dir
/secroot --block 4096 --threads 4<br>
<br>
noticed the huge max latency numbers with Sequential Writes:<br>
<br>
Unit information<o:p></o:p><br>
================<o:p></o:p><br>
File size<span style="">
</span>=
megabytes<o:p></o:p><span class="SpellE"><br>
Blk</span> Size<span style="">
</span><span style=""> </span><span style=""> </span><span style="">
</span>=
bytes<o:p></o:p><br>
Rate<span style="">
</span><span style=""> </span>=
megabytes per second<o:p></o:p><br>
CPU%<span style=""> </span><span style=""> </span>=
percentage of CPU used during the test<o:p></o:p><br>
Latency<span style=""> </span><span style=""> </span><span style="">
</span>=
milliseconds<o:p></o:p><br>
Lat%<span style=""> </span><span style=""> </span>=
percent of requests that took
longer than X seconds<o:p></o:p><br>
CPU <span class="SpellE">Eff</span><span style="">
</span><span style=""> </span>=
Rate divided by CPU% - throughput per <span class="SpellE"><span
class="GramE">cpu</span></span>
load<br>
<br>
<table class="MsoNormalTable" style="width: 477pt;" border="1"
cellpadding="0" width="636">
<tbody>
<tr style="">
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">Identifier<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt; width: 30pt;" width="40">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">File Size<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span class="SpellE"><span
style="font-family: Arial; color: black;">Blk</span></span><span
style="font-family: Arial; color: black;"> Size<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">Num <span class="SpellE">Thr</span><o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">Rate<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">Maximum CPU%<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span class="SpellE"><span
style="font-family: Arial; color: black;">Avg</span></span><span
style="font-family: Arial; color: black;"> Latency<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">Max Latency<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">Lat% >2s<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">Lat% >10s<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt; width: 28.5pt;" width="38">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">CPU <span class="SpellE">Eff</span><o:p></o:p></span></p>
</td>
</tr>
<tr style="">
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">Raw-device<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt; width: 30pt;" width="40">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">5000<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">4096<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">4<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">31.24<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">26.80%<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">0.364<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">5635.06<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">0.00242<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">0.00000<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt; width: 28.5pt;" width="38">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">117<o:p></o:p></span></p>
</td>
</tr>
<tr style="">
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span class="SpellE"><span
style="font-family: Arial; color: black;">Drbd</span></span><span
style="font-family: Arial; color: black;">-disconnected<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt; width: 30pt;" width="40">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">5000<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">4096<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">4<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">33.18<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">26.29%<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">0.319<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">110394.58<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">0.00190<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">0.00016<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt; width: 28.5pt;" width="38">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">126<o:p></o:p></span></p>
</td>
</tr>
<tr style="">
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span class="SpellE"><span
style="font-family: Arial; color: black;">Drbd-connected</span></span><span
style="font-family: Arial; color: black;"><o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt; width: 30pt;" width="40">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">5000<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">4096<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">4<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">20.88<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">50.18%<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">0.457<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">135712.09<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">0.00110<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt;">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">0.00008<o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt; width: 28.5pt;" width="38">
<p class="MsoNormal"><span
style="font-family: Arial; color: black;">42</span></p>
</td>
</tr>
</tbody>
</table>
<br>
My lab setting:<br>
<ul style="margin-top: 0in;" type="disc">
<li class="MsoNormal" style="">Two Linux nodes on
2.6.10_mvlcge401-pc_target-x86_pentium3-P3SMP.<br>
</li>
<li class="MsoNormal" style="">Dual-core Intel Xeon 2GHz CPU, 4GB
Memory, 1Gbits/s network interface.<br>
</li>
<li class="MsoNormal" style="">5.7GB partition on SCSI disk, ext2
file system with the "-T largefile4" option.</li>
<li class="MsoNormal" style="">DRBD rate=100M; protocal C;
sndbuf-size 1024k.</li>
</ul>
I don't believe the disk (~50MB/s) or network may be the factors here.
You can see the big number jump even with the DRBD disconnected mode.<br>
<br>
Any help on analyzing/identifying the problem will be greatly
appreciated.<br>
<br>
Weilin<br>
<br>
</blockquote>
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