Align status colors and naming for VDisk and PDisk "unavailable" states #3416
Description
Problem statement
Currently the coloring and naming logic for "disk is not working / not available" states differs between PDisks and VDisks:
- PDisk → "Unknown" / "Missing" / gray
- VDisk → "..Error" / "No data" / red
At the same time, from the user's point of view these two situations are semantically very close:
- PDisk "Not available" usually means the physical drive is dead / disconnected / failed.
- VDisk that was using this PDisk becomes "Missing" / "Lost" / red as a consequence.
We should make the "disk is not available / not functioning" state look and feel consistent between PDisk and VDisk layers.
Treat both as critical
PDisk "Not Available" / "Failed" / "Disconnected" → red color
VDisk "Missing" / "Lost" / "Unavailable" → red color (keep current)
→ Both cause and consequence are shown with the same high-severity color
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Update
New user feedback on VDisk “No data” status coloring
Received direct feedback from an active YDB user:
“I would prefer the ‘No data’ status for VDisks to be gray rather than red. During diagnostics, it should not blend / merge visually with disks that actually have real errors. Previously it used to be gray (especially when the node was just powered off / disabled), and that was much clearer. Now it’s red — and real error states are also red. Please do not mix these two very different conditions.”
User wants stronger visual separation between:
“something is really broken right now” (should stay red / attract attention)
“we simply don’t have current information about this VDisk” (should be de-emphasized → gray / muted)