<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div style="margin: 0px; font-stretch: normal; font-size: 13px; line-height: normal; font-family: "Helvetica Neue";" class="">Hi DRBD experts,</div><div style="margin: 0px; font-stretch: normal; font-size: 13px; line-height: normal; font-family: "Helvetica Neue";" class="">what are advantages of using drbd-attr resource agent in RedHat HA cluster vs “simple" resource constraint?</div><div style="margin: 0px; font-stretch: normal; font-size: 13px; line-height: normal; font-family: "Helvetica Neue";" class="">We have a SAN backed DRBD volume that is replicated from one HA cluster to another.</div><div style="margin: 0px; font-stretch: normal; font-size: 13px; line-height: normal; font-family: "Helvetica Neue";" class="">DRBD User Guide in paragraph 7.7 describes how to use drbd-attr resource agent to setup location constraint so that resource that depends on DRBD does not start before DRBD is promoted.</div><div style="margin: 0px; font-stretch: normal; font-size: 13px; line-height: normal; font-family: "Helvetica Neue";" class="">But in my tests same result can also be achieved by setting a resource constraint as below and not involve any rules that use drbd promotion score.</div><div style="margin: 0px; font-stretch: normal; font-size: 13px; line-height: normal; font-family: "Helvetica Neue";" class=""><br class=""></div><div style="margin: 0px; font-stretch: normal; font-size: 13px; line-height: normal; font-family: "Helvetica Neue";" class="">pcs constraint order promote DRBD-volume-master then DEPENDENT_resource score=INFINITY </div><div style="margin: 0px; font-stretch: normal; font-size: 13px; line-height: normal; font-family: "Helvetica Neue"; min-height: 15px;" class=""><br class=""></div><div style="margin: 0px; font-stretch: normal; font-size: 13px; line-height: normal; font-family: "Helvetica Neue"; min-height: 15px;" class="">Do I miss anything crucial here?</div><div style="margin: 0px; font-stretch: normal; font-size: 13px; line-height: normal; font-family: "Helvetica Neue";" class="">Thanks in advance for any opinion.</div><div style="margin: 0px; font-stretch: normal; font-size: 13px; line-height: normal; font-family: "Helvetica Neue";" class="">With kind regards,</div><div style="margin: 0px; font-stretch: normal; font-size: 13px; line-height: normal; font-family: "Helvetica Neue";" class="">Ivars Strazdins</div></body></html>