Hi,
I just did a new installation of Proxmox and selected ZFS mirror with 2 SSDs during the installation. I used the default values with ashift 12.
Unfortunately, the 4k read/write performance is increadable slow compared to mdadm raid 1.
On mdadm1 I had around 100k IOPS with 4k block size. Now with zfs it's 10k and I can't figure out why. I always use the default settings from proxmox.
Disks are:
SAMSUNG MZQLB960HAJR-00007
SAMSUNG MZQLW960HMJP-00003
This is on mdadm:
This is with ZFS
I read that some SSDs have ashift 13. Could this make such a big difference? If I wouldn't need to book a KVM console in the datacenter, I would just reinstall and try it out. That is why I am trying to understand the problem first.
I just did a new installation of Proxmox and selected ZFS mirror with 2 SSDs during the installation. I used the default values with ashift 12.
Unfortunately, the 4k read/write performance is increadable slow compared to mdadm raid 1.
On mdadm1 I had around 100k IOPS with 4k block size. Now with zfs it's 10k and I can't figure out why. I always use the default settings from proxmox.
Disks are:
SAMSUNG MZQLB960HAJR-00007
SAMSUNG MZQLW960HMJP-00003
This is on mdadm:
Code:
fio Disk Speed Tests (Mixed R/W 50/50) (Partition /dev/md2):
---------------------------------
Block Size | 4k (IOPS) | 64k (IOPS)
------ | --- ---- | ---- ----
Read | 398.70 MB/s (99.6k) | 466.46 MB/s (7.2k)
Write | 399.75 MB/s (99.9k) | 468.92 MB/s (7.3k)
Total | 798.45 MB/s (199.6k) | 935.39 MB/s (14.6k)
| |
Block Size | 512k (IOPS) | 1m (IOPS)
------ | --- ---- | ---- ----
Read | 449.28 MB/s (877) | 419.24 MB/s (409)
Write | 473.15 MB/s (924) | 447.16 MB/s (436)
Total | 922.43 MB/s (1.8k) | 866.41 MB/s (845)This is with ZFS
Code:
fio Disk Speed Tests (Mixed R/W 50/50) (Partition rpool/ROOT/pve-1):
---------------------------------
Block Size | 4k (IOPS) | 64k (IOPS)
------ | --- ---- | ---- ----
Read | 55.19 MB/s (13.7k) | 1.46 GB/s (22.9k)
Write | 55.28 MB/s (13.8k) | 1.47 GB/s (23.0k)
Total | 110.48 MB/s (27.6k) | 2.93 GB/s (45.9k)
| |
Block Size | 512k (IOPS) | 1m (IOPS)
------ | --- ---- | ---- ----
Read | 4.49 GB/s (8.7k) | 2.99 GB/s (2.9k)
Write | 4.73 GB/s (9.2k) | 3.19 GB/s (3.1k)
Total | 9.23 GB/s (18.0k) | 6.18 GB/s (6.0k)I read that some SSDs have ashift 13. Could this make such a big difference? If I wouldn't need to book a KVM console in the datacenter, I would just reinstall and try it out. That is why I am trying to understand the problem first.
Last edited:
