How can i create OSD on partition?

[bessome]

Hi

Is it possible create OSD on partition not on full disk?

i created partition

root@tlneht109srv01:~# sgdisk --print /dev/sda
Disk /dev/sda: 3904294912 sectors, 1.8 TiB
Logical sector size: 512 bytes
Disk identifier (GUID): 0F5B785B-348C-4F08-907F-CFB7B06E740D
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 3904294878
Partitions will be aligned on 2048-sector boundaries
Total free space is 4061 sectors (2.0 MiB)

Number Start (sector) End (sector) Size Code Name
1 2048 4095 1024.0 KiB EF02
2 4096 528383 256.0 MiB EF00
3 528384 104857600 49.7 GiB 8E00
4 104859648 3904294878 1.8 TiB 8300 ceph data

but i get error

root@tlneht109srv01:~# pveceph createosd /dev/sda4
not a valid block device

 

[dietmar]

We do not support such configuration, because it makes management more complex and it is no longer possible to replace damaged disks easily.

 

[bessome]

ok. but can i use part of SSD disk for journal?

 

[dietmar]

ok. but can i use part of SSD disk for journal?

Yes.

 

[Magneto]

Yes.

how would one do it?

 

[fabian]

if you pass a GPT partitioned block device as journal dev, ceph will automatically create a partition for the journal. just use the same device for multiple OSDs, and you get multiple journal partitions.