[ovirt-users] Re: DR on hyperconverged deployment

Hi, Thank you for your reply, but I already did all of that but I didn't understand everything and I got several problems on the way of doing the fail-over then a fail-back. I am writing this mail in hope to clarify those things. I will try to express my self correctly and give as much details as that I can. *The LAB :* My LAB contains two single-host oVirt-HCI platforms, one to act as the *primary site (the source)* the second as the *disaster-recovery site (the target)*. Each HCI site contains one data domain, the domain is comprised of a gluster volume which is backed by one brick. The volumes (source and target) have the same size, and they have been created within the process of the HCI deployment. *At the end of the deployment, I detached the deleted the gluster data domain on the target site, but I didn't delete the target volume.* My goal is to test the disaster recovery (active-passive DR to be precise) process on an HCI implementation. To test the fail-over and the fail-back process entirely. *Documentation* RHHI 1.7 Maintaining_Red_Hat_Hyperconverged_Infrastructure_for_Virtualization-en-US and I started my implementation I prepared all the ansible playbooks. *The Test procedure:* *Fail-over* 1 - Create a Windows10 VM on the source volume. 2 - Replicate to the DR site. 3 - Execute the fail-over procedure and test if the WM is usable in the target platform. 4 - Detach and Delete the data domain in the target platform without touching the target volume 5 - Make changes to the Win10 VM on the source volume (creating files and installing software) 6 - Replicate again to the DR site then execute another fail-over and see if the modification were synced. *Fail-back* 1 - Make changes to the Win10 VM on the target volume (deleting files) *and especially creating a snapshot* 2 - Detach and Delete the data domain in the source platform without touching the source volume. 3 - Replicate to the source site. 4 - Execute the clean up playbook 5 - Execute the fail-over and WM is usable in the source platform and that the modifications were synced especially the snapshot *Things I need to confirm :* 1 - When creating the geo-replication from the primary site to the target site, we get to a point where we have to create "*Scheduling regular backups using geo-replication*", from my understanding it's like a cron job that starts the geo-replication at a specific time (or day time), and from my testing, the geo-replication starts syncing at that precise time and when its "*CRAWL STATUS*" reaches "Changelog Crawl" it stops the synchronization. In other terms when the geo-replication reaches the same date as the check-point (the specific time). The smallest time you can get from the configuration window is 24hours, which means in the event of a disaster, you can at most recover the data from the day before. *Is this correct?* *Problems encountered during the test:* *Fail-over* 1 - When executing the fail-over the first time (ansible-playbook dr-rhv-failover.yml --tags "fail_over"), the import of the target data domain failed with the error : *An exception occurred during task execution. To see the full traceback, use -vvv. The error was: ovirtsdk4.Error: Fault reason is "Operation Failed". Fault detail is "[Error in creating a Storage Domain. The selected storage path is not empty (probably contains another Storage Domain). Either remove the existing Storage Domain from this path, or change the Storage path).]". HTTP response code is 400. *I tried manually to import the domain from oVirt's admin console and I got the same error. so I did the following - I deleted the target volume and the brick and the sub-directory of the brick. - I recreated the volume from scratch. - I redid the geo-replication synchronization from the source. - I executed the fail-over and this time the target data domain was imported correctly and the Win10 VM was started correctly. 2 - I detached then deleted the target data domain without touching the target volume, then I made change to the Win10 VM on the source site, then I created a new schedule of geo-replication, and after the replication I executed another fail-over. - The Win10 VM started successfully and the changes made were synced. *Fail-back* 1 - The documentation doesn't explain the fail-back procedure thoroughly. It doesn't explain what does the dr-cleanup.yml do? 2 - When launching the fail-back playbook at some point I get this message : *TASK [oVirt.disaster-recovery : Failback Replication Sync pause] ****************************************************************************************************************************[oVirt.disaster-recovery : Failback Replication Sync pause][Failback Replication Sync] Please press ENTER once the destination storage domains are ready to be used for the destination setup:* What does this mean? 3 - I did some changed on the Win10 VM and I created snapshot of that VM. 4.a - To replicate the data from the target site to the primary site I create a new geo-replication from the target volume to the source volume, but I get a warning that the source volume was not empty so I forced the geo-replication creation, then : - I detached and deleted the source data domain without touching the source volume. - I started the geo-replication manually (without a schedule) and when it reached the state of "Changelog Crawl" I stopped it. - I executed the clean-up plyabook then I executed the fail-back playbook - I got the error : the import of the source data domain failed with the error : *An exception occurred during task execution. To see the full traceback, use -vvv. The error was: ovirtsdk4.Error: Fault reason is "Operation Failed". Fault detail is "[Error in creating a Storage Domain. The selected storage path is not empty (probably contains another Storage Domain). Either remove the existing Storage Domain from this path, or change the Storage path).]". HTTP response code is 400.* 4.b - So I redid the test but, - I deleted the source volume and its brick, then I created them again. - I started the geo-replication manually (without a schedule) and when it reached the state of "changelog" I stopped it. - I executed the clean-up plyabook then I executed the fail-back playbook - I got the error : the import of the source data domain failed with the error : *An exception occurred during task execution. To see the full traceback, use -vvv. The error was: ovirtsdk4.Error: Fault reason is "Operation Failed". Fault detail is "[Error in creating a Storage Domain. The selected storage path is not empty (probably contains another Storage Domain). Either remove the existing Storage Domain from this path, or change the Storage path).]". HTTP response code is 400.* 4.c - I redid the test but : - I deleted the source volume and its brick, then I created them again. - I started the geo-replication using a shedule this time - I executed the clean-up plyabook then I executed the fail-back playbook - *This time the source data domain was imported correctly and the Win10 VM was started and the modifications were synced.* - The snapshot was imported, but there was another snapshot with it called "Win10-TMPDR". Regards. Le jeu. 2 avr. 2020 à 08:42, Eyal Shenitzky <eshenitz(a)redhat.com&gt; a écrit :