<div>Hi,</div><div><br></div><div>I have tested 3 kinds of distributed&nbsp;replica volume: 4 * 2, 3* 2 and 2*2. I suppose 4 * 2 should achieve the best IOPS, however, their performance seems similar.&nbsp;</div><div><br></div><div>I have tested with "<span style="font-family: arial, sans, sans-serif; font-size: 13px;"><b>dd if=/dev/zero of=/mnt/glusterfs/block8 bs=128M count=1</b>" and "</span><span style="font-family: arial, sans, sans-serif; font-size: 13px;"><b>dd if=/dev/zero of=/mnt/glusterfs/block8 bs=32M count=8</b>". All bricks are on virtual machines, &nbsp;with same hardware: 2 cores cpu, 8G memory.</span></div><div><span style="font-family: arial, sans, sans-serif; font-size: 13px;"><br></span></div><style type="text/css"><!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--></style><style type="text/css"><!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--></style><div>The following is my volume configuration:</div><div><style type="text/css"><!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--></style><table cellspacing="0" cellpadding="0" dir="ltr" border="1" style="table-layout:fixed;font-size:13px;font-family:arial,sans,sans-serif;border-collapse:collapse;border:1px solid #ccc"><colgroup><col width="282"></colgroup><tbody><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Volume Name: rep4&quot;}">Volume Name: rep4</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Type: Distributed-Replicate&quot;}">Type: Distributed-Replicate</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Volume ID: b2ad2871-cfad-4f2c-afdb-38c2c4d6239c&quot;}">Volume ID: b2ad2871-cfad-4f2c-afdb-38c2c4d6239c</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Status: Started&quot;}">Status: Started</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Number of Bricks: 2 x 2 = 4&quot;}">Number of Bricks: 2 x 2 = 4</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Transport-type: tcp&quot;}">Transport-type: tcp</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Bricks:&quot;}">Bricks:</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick1: 192.168.16.145:/home/vagrant/rep4&quot;}">Brick1: 192.168.16.145:/home/vagrant/rep4</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick2: 192.168.16.146:/home/vagrant/rep4&quot;}">Brick2: 192.168.16.146:/home/vagrant/rep4</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick3: 192.168.16.82:/home/vagrant/rep4&quot;}">Brick3: 192.168.16.82:/home/vagrant/rep4</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick4: 192.168.16.114:/home/vagrant/rep4&quot;}">Brick4: 192.168.16.114:/home/vagrant/rep4</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;"></td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Volume Name: rep6&quot;}">Volume Name: rep6</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Type: Distributed-Replicate&quot;}">Type: Distributed-Replicate</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Volume ID: 2cbcefce-da7a-4823-aee7-432c40f3ae55&quot;}">Volume ID: 2cbcefce-da7a-4823-aee7-432c40f3ae55</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Status: Started&quot;}">Status: Started</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Number of Bricks: 3 x 2 = 6&quot;}">Number of Bricks: 3 x 2 = 6</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Transport-type: tcp&quot;}">Transport-type: tcp</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Bricks:&quot;}">Bricks:</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick1: 192.168.16.49:/home/vagrant/rep6&quot;}">Brick1: 192.168.16.49:/home/vagrant/rep6</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick2: 192.168.16.114:/home/vagrant/rep6&quot;}">Brick2: 192.168.16.114:/home/vagrant/rep6</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick3: 192.168.16.141:/home/vagrant/rep6&quot;}">Brick3: 192.168.16.141:/home/vagrant/rep6</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick4: 192.168.16.145:/home/vagrant/rep6&quot;}">Brick4: 192.168.16.145:/home/vagrant/rep6</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick5: 192.168.16.146:/home/vagrant/rep6&quot;}">Brick5: 192.168.16.146:/home/vagrant/rep6</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick6: 192.168.16.82:/home/vagrant/rep6&quot;}">Brick6: 192.168.16.82:/home/vagrant/rep6</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;"></td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Volume Name: rep8&quot;}">Volume Name: rep8</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Type: Distributed-Replicate&quot;}">Type: Distributed-Replicate</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Volume ID: ea77934c-bd5d-4578-8b39-c02402d00739&quot;}">Volume ID: ea77934c-bd5d-4578-8b39-c02402d00739</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Status: Started&quot;}">Status: Started</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Number of Bricks: 4 x 2 = 8&quot;}">Number of Bricks: 4 x 2 = 8</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Transport-type: tcp&quot;}">Transport-type: tcp</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Bricks:&quot;}">Bricks:</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick1: 192.168.16.145:/home/vagrant/rep8&quot;}">Brick1: 192.168.16.145:/home/vagrant/rep8</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick2: 192.168.16.146:/home/vagrant/rep8&quot;}">Brick2: 192.168.16.146:/home/vagrant/rep8</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick3: 192.168.16.114:/home/vagrant/rep8&quot;}">Brick3: 192.168.16.114:/home/vagrant/rep8</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick4: 192.168.16.82:/home/vagrant/rep8&quot;}">Brick4: 192.168.16.82:/home/vagrant/rep8</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick5: 192.168.16.141:/home/vagrant/rep8&quot;}">Brick5: 192.168.16.141:/home/vagrant/rep8</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick6: 192.168.16.49:/home/vagrant/rep8&quot;}">Brick6: 192.168.16.49:/home/vagrant/rep8</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick7: 192.168.16.144:/home/vagrant/rep8&quot;}">Brick7: 192.168.16.144:/home/vagrant/rep8</td></tr><tr style="height:21px;"><td style="padding:2px 3px 2px 3px;vertical-align:bottom;" data-sheets-value="{&quot;1&quot;:2,&quot;2&quot;:&quot;Brick8: 192.168.16.112:/home/vagrant/rep8&quot;}">Brick8: 192.168.16.112:/home/vagrant/rep8</td></tr></tbody></table></div><div><br></div><div>According to "http://moo.nac.uci.edu/~hjm/Performance_in_a_Gluster_Systemv6F.pdf",&nbsp;</div><div><i>&gt; To scale out performance, enterprises need simply add additional storage server nodes, and will generally see linear performance improvements.</i></div><div><br></div><div>I wonder how can I achieve&nbsp;&nbsp;linear performance improvements? Have I tested in the wrong way?</div><div><div style="color:#909090;font-family:Arial Narrow;font-size:12px">------------------</div><div style="font-size:14px;font-family:Verdana;color:#000;"><div><font size="2">Regards,</font></div><div><font size="2">Haoyuan Ge</font></div></div></div><div>&nbsp;</div>