Bug 210521
Summary: | btrfs replace doesn't honor the -r option on raid5 and raid6 | ||
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Product: | File System | Reporter: | Andrej Podzimek (andrej) |
Component: | btrfs | Assignee: | BTRFS virtual assignee (fs_btrfs) |
Status: | NEW --- | ||
Severity: | low | ||
Priority: | P1 | ||
Hardware: | All | ||
OS: | Linux | ||
Kernel Version: | 5.9.11 | Subsystem: | |
Regression: | No | Bisected commit-id: |
Description
Andrej Podzimek
2020-12-06 19:27:42 UTC
In retrospect, I guess this is/was because the parity is not checksummed, so parity blocks have to be recalculated from the other drives to make sure everything is correct. That's fine. But in that case I would expect, for an N-drive array, a load of (100% / (N - redundancy)) on drives other than the replaced one. This was quite obviously not the case; the load on the other drives was like >50% on a 8-drive array. (Admittedly, I can't rule out the possibility that the relativey high load was in fact a symptom of a *low* load combined with power saving features and inefficiency that comes with them.) |