Lets do it differently, i think you dont care about sync writes or parallelism things etc.
I think you want simply better performance. There is indeed a performance issue with ZVOL's (every VM on your ZFS Storage) is using Zvol.
Except if you defined a storage as "Directory" on the ZFS Pool. (Doing that will speed up the performance)
ZVOL's are simply the slowest possible Storage method for VM's, they don't support most of the ZFS features, like special small blocks and more. Zvols simply dont get many attention in zfs development.
However with 2.2.4, there is a fix, where Zvols will get probably twice as fast, so just wait.
I sadly stumbled across this either. For example the RAW Storage Performance has here ~40GB/s Read speed and 20GB/s Write speed.
With LVM/LVM-thin im getting around 80% of that speed. With ZFS on the Host im hitting some Hard-Limit at 6GB/s Write and 6GB/s Read.
Read and Write gets limited to around 6GB/s.
Inside a ZVOL-VM im getting around 1GB/s xD
It's still fast thanks to 8x Micron 7450 Max, but still almost 20 times slower as it could be.
With 2.2.4 i expect to get around 2-3GB/s inside the VM, but i wouldn't expect to much, so it will probably be 1,5-2GBs.
However, things will get a lot better with updates, there is a massive development going on, but will still take at least a year, till things gets better for NVME's.
Cheers
I think you want simply better performance. There is indeed a performance issue with ZVOL's (every VM on your ZFS Storage) is using Zvol.
Except if you defined a storage as "Directory" on the ZFS Pool. (Doing that will speed up the performance)
ZVOL's are simply the slowest possible Storage method for VM's, they don't support most of the ZFS features, like special small blocks and more. Zvols simply dont get many attention in zfs development.
However with 2.2.4, there is a fix, where Zvols will get probably twice as fast, so just wait.
I sadly stumbled across this either. For example the RAW Storage Performance has here ~40GB/s Read speed and 20GB/s Write speed.
With LVM/LVM-thin im getting around 80% of that speed. With ZFS on the Host im hitting some Hard-Limit at 6GB/s Write and 6GB/s Read.
Read and Write gets limited to around 6GB/s.
Inside a ZVOL-VM im getting around 1GB/s xD
It's still fast thanks to 8x Micron 7450 Max, but still almost 20 times slower as it could be.
With 2.2.4 i expect to get around 2-3GB/s inside the VM, but i wouldn't expect to much, so it will probably be 1,5-2GBs.
However, things will get a lot better with updates, there is a massive development going on, but will still take at least a year, till things gets better for NVME's.
Cheers
