NVMe Low-Level Format
Simplyblock generally requires NVMe devices with support for 4K block size. This is the case for almost all Enterprise-grade NVMe devices, nevertheless it is recommended to ensure support before deployment.
Alternatively, 512 bytes block only supporting devices can be used. However, they must provide 4K write atomiticy or 4K torn write protection.
Warning
The only devices with 512 bytes block size, that are also known to support 4K torn write protection, are the NVMe devices provided by AWS.
Devices must not contain active mount points under Linux. Simplyblock fails to claim devices that are mounted or otherwise marked as busy.
Additionally, partitions must be removed from devices. Simplyblock can only claim unpartitioned devices. Alternatively, simplyblock can remove partitions during the optional formatting process as part of the deployment. However, partitioned devices will never be automatically selected.
Danger
Simplyblock optionally performs a low-level format of selected devices during the deployment process. This erases all data on the devices without recovery option!
Use lsblk to identify available NVMe devices without active mount points.
[demo@demo-3 ~]# sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sda 8:0 0 30G 0 disk
├─sda1 8:1 0 1G 0 part /boot
└─sda2 8:2 0 29G 0 part
├─rl-root 253:0 0 26G 0 lvm /
└─rl-swap 253:1 0 3G 0 lvm [SWAP]
nvme3n1 259:0 0 6.5G 0 disk
nvme2n1 259:1 0 70G 0 disk
nvme1n1 259:2 0 70G 0 disk
nvme0n1 259:3 0 70G 0 disk
The example shows four NVMe devices. Three devices of 70 GiB each and one device with 6.5 GiB storage capacity. None of those devices have any active mount points and partitions.
To find the correct LBA format (lbaf) for each of the devices, the nvme CLI can be used.
sudo nvme id-ns /dev/nvmeXnY
The output depends on the NVMe device itself, but looks something like this:
[demo@demo-3 ~]# sudo nvme id-ns /dev/nvme0n1
NVME Identify Namespace 1:
...
lbaf 0 : ms:0 lbads:9 rp:0
lbaf 1 : ms:8 lbads:9 rp:0
lbaf 2 : ms:16 lbads:9 rp:0
lbaf 3 : ms:64 lbads:9 rp:0
lbaf 4 : ms:0 lbads:12 rp:0 (in use)
lbaf 5 : ms:8 lbads:12 rp:0
lbaf 6 : ms:16 lbads:12 rp:0
lbaf 7 : ms:64 lbads:12 rp:0
From this output, the required lbaf configuration can be found. lbads must be 12. Simplyblock will automatically choose lbads: 12 with any ms > 0 if available, as
this significantly improves performance if DIF (data integrity checking) is used.
If only ms: 0 is available, simplyblock will use this as a fallback option.
Warning
This operation needs to be repeated for each NVMe device that will be handled by simplyblock.