Ceph OSD WAL disk

[Protuberantzev]

I found out that the DB disk needs to plan 4% of the space from the OSD. But I didn't find any mention of the WAL disk. How much should I allocate for it? Maybe just put it on the DB and forget it? I would be grateful if someone could tell me.

 

[fiona]

Hi,
you don't really need an additional WAL disk, if you already have a DB disk. From the CEPH documentation:

If there is only a small amount of fast storage available (e.g., less than a gigabyte), we recommend using it as a WAL device. If there is more, provisioning a DB device makes more sense. The BlueStore journal will always be placed on the fastest device available, so using a DB device will provide the same benefit that the WAL device would while also allowing additional metadata to be stored there (if it will fit).

 

[Protuberantzev]

Really Thank you!