I don't want no scrubs (for read-only Crucible backends)#1028
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Propolis should not launch scrubs when constructing a Crucible backend for a read-only disk. Because the Crucible volume itself is read-only, the scrub will never succeed, so we shouldn't waste time attempting it. This commit changes the `CrucibleBackend` to skip launching scrubs if the backend is readonly.
jmpesp
approved these changes
Jan 29, 2026
leftwo
approved these changes
Jan 30, 2026
| // | ||
| // We should not scrub read-only volumes, as we cannot write back to | ||
| // them, due to...you know, being read-only. So just don't do that. | ||
| if !opts.is_read_only() && volume.has_read_only_parent() { |
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I'm not convinced Nexus can construct a read only volume with a read_only_parent, but I suppose nothing stops you from sending propolis a toml directly that contains such a beast. So, it's probably best to just prevent it.
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@jmpesp told me it was possible, though I'm not sure if it will currently happen for the way we construct ro disks or not?
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Propolis should not launch scrubs when constructing a Crucible backend for a read-only disk. Because the Crucible volume itself is read-only, the scrub will never succeed, so we shouldn't waste time attempting it.
This commit changes the
CrucibleBackendto skip launching scrubs if the backend is readonly.