{"id":2779,"date":"2024-03-02T18:14:51","date_gmt":"2024-03-02T23:14:51","guid":{"rendered":"https:\/\/blog.lufamily.ca\/kang\/?p=2779"},"modified":"2024-03-02T18:14:52","modified_gmt":"2024-03-02T23:14:52","slug":"lvm-to-zfs-migration","status":"publish","type":"post","link":"https:\/\/blog.lufamily.ca\/kang\/2024\/03\/02\/lvm-to-zfs-migration\/","title":{"rendered":"LVM to ZFS Migration"},"content":{"rendered":"\n

In a previous post<\/a>, I described the hardware changes that I made to facilitate additional drive slots on my NAS Media Server.<\/p>\n\n\n\n

We now need to migrate from an LVM system consisting of 40TB of redundant mirrored storage using mdadm<\/code> to a ZFS system consisting of a single pool and a dataset. Below is a diagram depicting the logical layout of the old and the intended new system.<\/p>\n\n\n\n

\n\n \n \n \n \n \n \n \n \n \n \n 40TB of Redundant Storage\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n 40TB of Redundant Storage\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n Logical Volume (LV)\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n Logical Volume (LV)\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n EXT 4 File System for Media Storage\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n EXT 4 File System for Media Storage\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n Old Storage System\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n Old Storage System\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n 50TB of Redundant Storage\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n 50TB of Redundant Storage\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n ZFS Dataset\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n ZFS Dataset\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n New Storage System\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n New Storage System\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n \n LV Group of 4 Physical Volumes (PV)\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n LV Group of 4 Physical Volumes (PV)\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n \n PV\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n PV\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n 10TB
mdadm mirror\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n 10TB…\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n \n \n \n \n \n PV\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n PV\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n 8TB
mdadm mirror\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n 8TB…\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n \n \n \n \n \n PV\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n PV\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n 10TB
mdadm mirror\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n 10TB…\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n \n \n \n \n \n PV\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n PV\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n 12TB
mdadm mirror\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n 12TB…\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n \n \n \n \n \n ZFS Pool\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n ZFS Pool\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n \n 12TB
Mirror VDEV\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n 12TB…\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n \n \n \n \n \n 10TB
Mirror VDEV\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n 10TB…\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n \n \n \n \n \n 8TB
Mirror VDEV\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n 8TB…\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n \n \n \n \n \n 10TB
Mirror VDEV\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n 10TB…\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n \n \n \n \n \n 6TB
Mirror VDEV\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n 6TB…\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n \n \n \n \n \n 4TB
Mirror VDEV\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n 4TB…\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n \n \n \n \n \n \n \n 512GB
L2ARC Cache\n <\/div>\n <\/div>\n <\/div><\/foreignObject\n >\n \n 512GB…\n <\/text>\n <\/switch>\n <\/g>\n \n \n \n \n <\/g>\n<\/svg>\n<\/center>\n\n\n\n

Before the migration, we must backup all the data from the LVM system. I cobbled together a collection of old hard drives and then proceeded to create another LVM volume as the temporary storage of the content. This temporary volume will not have any redundancy capability, so if any one of the old hard drives fails, then out goes all the content. The original LVM system is mounted on \/mnt\/airvideo<\/code> and the temporary LVM volume is mounted on \/mnt\/av2<\/code>.<\/p>\n\n\n\n

I used the command below to proceed with the backup.<\/p>\n\n\n\n

sudo rsync --delete -aAXv \/mnt\/airvideo \/mnt\/av2 > ~\/nohup.avs.rsync.out 2>&1 &<\/code><\/pre>\n\n\n\n
I can then monitor the progress of the backup with:<\/p>\n\n\n\n
tail -f ~\/nohup.avs.rsync.out<\/code><\/pre>\n\n\n\n
The backup took a little more than 7 days to copy around 32 TB of data from our NAS server. During this entire process, all of the NAS services continued to run, so that downtime was almost non-existent.<\/p>\n\n\n\n
Once the backup is completed, I wanted to move all the services to the backup before I started to dismantle the old LVM volume. The following steps were done:<\/p>\n\n\n\n