gelmi Posted January 22, 2023 Share Posted January 22, 2023 Hi, Currently with a ZFS plugin I have created ZFS pool mirror from 2 x SSD (I guess I would be able to import that as native ZFS pool after 6.12). I have another server (main) with TrueNas Scale in other location and running there couple of VMs. TrueNas creates their VM disks as ZVOL as far as I know. I am creating daily snapshots independently for each VM (snapshots of the whole zvols). I would like to use 'zfs send | zfs recv' to replicate these snapshots as backup from TrueNas to Unraid. I think there should be no issue with that with a plugin installed (correct me if I am wrong). Since, both Unraid and TrueNas Scale uses KVM, I was wondering if I could use Unraid VMs as temporary/backup VMs in case when there is some hardware failure on the main server - probably just for couple of hours? ZVOLs are block storages and I can see that they are being added as virtual block storage in /dev/zd(x). I can check which one is which by running 'ls -l /dev/zvol/<poolname>'. I have briefly tested that I could just add that block storage to the Ubuntu VM as: <disk type='block' device='disk'> <driver name='qemu' type='raw' cache='writeback'/> <source dev='/dev/zd0'/> <target dev='hdc' bus='sata'/> <boot order='1'/> <address type='drive' controller='0' bus='0' target='0' unit='2'/> </disk> I would also add similar RAM/CPU resources as on TrueNas machine and I would already have a reverse-proxy in place to match CloudFlare/Domains (DNS) setup. Couple of question here: 1. Should I use cache='writeback' or cache='none'? 2. Should I use bus='sata' or virtio? After TrueNas VMs are operational again, I would manually move changes in databases (only timeseries data) from Unraid to TrueNas VM databases, so everything is up to date and I do not lose any data between the snapshot and the time when TrueNas machine failed. That way I do not have to deal with transferring snapshots from Unraid to TrueNas. Is everything OK with this idea or should I be worried about something? The alternative would be to have an additional TrueNas server as fallback or some cloud hosting fallback architecture. Quote Link to comment
gelmi Posted January 26, 2023 Author Share Posted January 26, 2023 Hi again, Any hits with this? Quote Link to comment
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