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<p class="MsoNormal">Hi Everyone, new to this list so any help would be greatly appreciated. Just installed DRBD and set it up on 2-nodes. I have then introduced a 3<sup>rd</sup> node to the cluster and it was to say the least cumbersome. The steps that I have
followed were the below:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">#drbdadm down drbd-2 (this has been run on all nodes)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I then followed the DRBD user guide 9.7.8 Changing the meta-data which suggest to run –max-peers=<N><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">#drbdadm create-md drbd-2 --max-peers=3<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Move internal meta data from last-known position?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">[need to type 'yes' to confirm] yes<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">md_offset 10842271744<o:p></o:p></p>
<p class="MsoNormal">al_offset 0<o:p></o:p></p>
<p class="MsoNormal">bm_offset 0<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Found ext3 filesystem<o:p></o:p></p>
<p class="MsoNormal"> 9437184 kB data area apparently used<o:p></o:p></p>
<p class="MsoNormal"> 0 kB left usable by current configuration<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Device size would be truncated, which<o:p></o:p></p>
<p class="MsoNormal">would corrupt data and result in<o:p></o:p></p>
<p class="MsoNormal">'access beyond end of device' errors.<o:p></o:p></p>
<p class="MsoNormal">You need to either<o:p></o:p></p>
<p class="MsoNormal"> * use external meta data (recommended)<o:p></o:p></p>
<p class="MsoNormal"> * shrink that filesystem first<o:p></o:p></p>
<p class="MsoNormal"> * zero out the device (destroy the filesystem)<o:p></o:p></p>
<p class="MsoNormal">Operation refused.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">So I increased the LV and the same output was received and then reduced the ext3 filesystem with resize2fs but still same output.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Bottom line, to have it working I had to:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"># drbdadm wipe-md drbd-2<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Do you really want to wipe out the DRBD meta data?<o:p></o:p></p>
<p class="MsoNormal">[need to type 'yes' to confirm] yes<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Wiping meta data...<o:p></o:p></p>
<p class="MsoNormal">DRBD meta data block successfully wiped out.<o:p></o:p></p>
<p class="MsoNormal"># drbdadm create-md drbd-2 --max-peers=3<o:p></o:p></p>
<p class="MsoNormal">md_offset 10842271744<o:p></o:p></p>
<p class="MsoNormal">al_offset 10842238976<o:p></o:p></p>
<p class="MsoNormal">bm_offset 10841243648<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Found ext3 filesystem<o:p></o:p></p>
<p class="MsoNormal"> 9437184 kB data area apparently used<o:p></o:p></p>
<p class="MsoNormal"> 10587152 kB left usable by current configuration<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Even though it looks like this would place the new meta data into<o:p></o:p></p>
<p class="MsoNormal">unused space, you still need to confirm, as this is only a guess.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Do you want to proceed?<o:p></o:p></p>
<p class="MsoNormal">[need to type 'yes' to confirm] yes<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">initializing activity log<o:p></o:p></p>
<p class="MsoNormal">initializing bitmap (972 KB) to all zero<o:p></o:p></p>
<p class="MsoNormal">Writing meta data...<o:p></o:p></p>
<p class="MsoNormal">New drbd meta data block successfully created.<o:p></o:p></p>
<p class="MsoNormal">success<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Afterwards I deleted the metadata on the secondary nodes and recreated it, and after a full-sync the files were synced from the primary. Finally my question is, is this the correct procedure or maybe there is a better way to achieve the
introduction of new nodes in the DRBD cluster?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Systems details:<o:p></o:p></p>
<p class="MsoNormal">CentOS Linux release 7.6.1810 (Core)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">kmod-drbd90-9.0.16-1.el7_6.elrepo.x86_64<o:p></o:p></p>
<p class="MsoNormal">drbd90-utils-9.6.0-1.el7.elrepo.x86_64<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks in advance for any feedback<o:p></o:p></p>
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