ZFS migrate from RAID1 to RAIDZ-1

[kprkprk]

Hi!
I have a working Proxmox 6.1 with a ZFS (Called "DATARAID") in a RAID1 with all disk hard images of working machines. I want to "change it" to a ZFS RAIDZ-1 (Adding a new disk, because I read that is better read-write than actual RAID1) without losing data. I know that it will be some offline time, but i really don't know much about ZFS and changing RAID forms and make proxmox see it as same ZFS disk, to not configure again all..
Someone can help me??

 

[aaron]

Changing a RAID1 (mirror) to a RAIDZ1 is not possible. You would have to move your data somewhere else, destroy that ZFS pool and create a new one with the 3 disks.

But where did you get the information that a RaidZ1 has better performance than a Raid1? For better performance, you could make your pool a "RAID10" by adding another mirror to it. Be aware though that the new mirror will only be used for new data written to the pool.
It will survive 2 disks failures but they have to be the right disks, one in each mirror, not two in the same mirror.

 

[kprkprk]

Hi
I knew that is not directly possible, but.. I'm not familiar with subvolumes and this type of things, and I didn't know how to "copy" to a new disk, delete all raid, create new raid (z1, 10,etc), and restore all, without recreating all VM..

There are some pages like https://calomel.org/zfs_raid_speed_capacity.html and https://icesquare.com/wordpress/zfs-performance-mirror-vs-raidz-vs-raidz2-vs-raidz3-vs-striped/ that see that RAIDZ-1 is better performance than mirror

2x 4TB, mirror (raid1), 3.7 TB, w=106MB/s , rw=50MB/s , r=488MB/s
3x 4TB, raidz1 (raid5), 7.5 TB, w=225MB/s , rw=56MB/s , r=619MB/s
4x 4TB, 2 striped mirrors, 7.5 TB, w=226MB/s , rw=53MB/s , r=644MB/s
4x 4TB, raidz2 (raid6), 7.5 TB, w=204MB/s , rw=54MB/s , r=183MB/s
---
Mirror 473MB/s Write 598MB/s Read
RAIDZ1 604MB/s Write 631MB/s Read

Well, in this pages there is not much a RAID1 vs RAID10 performance... And see that RAIDZ2 has less read performance than RAID10 inclusive in one of this tests

I didn't catch you in the part of making a RAID10 only adding a mirror to it..