<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi everybody,<div><br></div><div>I have an OLTP application running on a 2 node cluster on top of DRBD.</div><div><br></div><div>( <b>App</b>: CentOS Linux --> MySql --> Perl --> Apache )</div><div>( <b>Disk</b>: Disk Partition --> LV --> DRBD --> Mount point )</div><div>( <b>Cluster</b>: DRBD <-- primary/primary --> DRBD )</div><div><br></div><div>Before I moved to this DRBD cluster setup, my response-time-graph was very consistent and stable (flatline).</div><div>After I moved to DRBD, the response-time-graph became inconsistent with peaks that don't make sense. Eg. typical response time would be 0.2 seconds. Now I have responses of, for instance 3 or more seconds every now and then). The cluster hardware have more CPU's, more memory, faster everything, and yet the response-times are slower and less consistent than my "no DRBD" setup. It's been running in production with DRBD for several months. Everything seems stable, other than the inconsistent performance.</div><div><br></div><div>Could this be a misconfiguration on my part (or lack of tuning), or is this normal? The server load is under 40%. The disks aren't very busy either. The response-time-graph is fed by a few queries on the database across important tables.</div><div><br></div><div>Any guidance or help will be MUCHOS appreciated :)</div><div><br></div><div>Thanks and Regards,</div><div><br><div apple-content-edited="true"> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><span class="Apple-style-span" style="font-size: 12px; text-align: justify; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; 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