Herr_Merlin
Patron
- Joined
- Oct 25, 2019
- Messages
- 200
I assume a rather stupid question:
- How do writes to metadata vdevs work?
Assuming you have a pool of disk, a pair of ssds as metadata vdev and some mirrored devices as slog.
Assumention:
Data: RAM+SLOG -> disk -> done
Metadata RAM+SLOG -> disk -> done
Another possibility:
Data: RAM+SLOG -> disk -> done
Metadata RAM -> disk -> done
So the rather stupid question is: Do you need SSDs with power loss protection for the Metadata or not. If all data is going through SLOG there is no need. If not and the writes happen in parallel PLP would be strongly needed.
Another question: How is the dedup data handled for a dedup vdev?
Will those data always go though SLOG if not PLP would be needed as well.
- How do writes to metadata vdevs work?
Assuming you have a pool of disk, a pair of ssds as metadata vdev and some mirrored devices as slog.
Assumention:
Data: RAM+SLOG -> disk -> done
Metadata RAM+SLOG -> disk -> done
Another possibility:
Data: RAM+SLOG -> disk -> done
Metadata RAM -> disk -> done
So the rather stupid question is: Do you need SSDs with power loss protection for the Metadata or not. If all data is going through SLOG there is no need. If not and the writes happen in parallel PLP would be strongly needed.
Another question: How is the dedup data handled for a dedup vdev?
Will those data always go though SLOG if not PLP would be needed as well.