Hello,
I'm running a server with 4xSAS raidz plus 1xNVMe SSD (SAMSUNG MZVLB512HAJQ). The NVMe drive is split in 3 parts:
Every vdev uses ashift=12 but I've read in different places that SAMSUNG SSD like the PM981 could benefit from ashift=13.
Is it possible to change ashift for vdevs gpt/nvmedata, gpt/nvmelog, gpt/nvmecache (destroy and recreate) and still be able to add gpt/nvmelog & gpt/nvmecache back to my "sas" pool? (it'll end up mixing ashift=12 for SAS HDD and ashift=13 for NVMe backed vdevs).
I'm a bit worried that keeping ashift=12 could yield to write amplification on the NVMe drive, degrading performance where I need it most.
I'm running a server with 4xSAS raidz plus 1xNVMe SSD (SAMSUNG MZVLB512HAJQ). The NVMe drive is split in 3 parts:
Code:
# zpool status
pool: nvme
state: ONLINE
scan: none requested
config:
NAME STATE READ WRITE CKSUM
nvme ONLINE 0 0 0
gpt/nvmedata ONLINE 0 0 0
errors: No known data errors
pool: sas
state: ONLINE
scan: none requested
config:
NAME STATE READ WRITE CKSUM
sas ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
da0p3 ONLINE 0 0 0
da1p3 ONLINE 0 0 0
da2p3 ONLINE 0 0 0
da3p3 ONLINE 0 0 0
logs
gpt/nvmelog ONLINE 0 0 0
cache
gpt/nvmecache ONLINE 0 0 0
Every vdev uses ashift=12 but I've read in different places that SAMSUNG SSD like the PM981 could benefit from ashift=13.
Is it possible to change ashift for vdevs gpt/nvmedata, gpt/nvmelog, gpt/nvmecache (destroy and recreate) and still be able to add gpt/nvmelog & gpt/nvmecache back to my "sas" pool? (it'll end up mixing ashift=12 for SAS HDD and ashift=13 for NVMe backed vdevs).
I'm a bit worried that keeping ashift=12 could yield to write amplification on the NVMe drive, degrading performance where I need it most.