Re: [PATCH 01/19] btrfs: require at least 4 devices for RAID 6
"H. Peter Anvin" <[email protected]>
| Newsgroups | gmane.linux.ports.riscv,gmane.linux.kernel,gmane.linux.ports.arm.kernel,gmane.linux.ports.ppc64.devel,gmane.linux.kernel.cryptoapi,gmane.comp.file-systems.btrfs,gmane.linux.kernel.cross-arch,gmane.linux.raid |
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| Message-ID | <[email protected]> |
On May 14, 2026 12:51:59 PM PDT, Goffredo Baroncelli <[email protected]> wrote: >On 13/05/2026 07.47, Christoph Hellwig wrote: >> On Tue, May 12, 2026 at 01:42:31PM +0200, David Sterba wrote: > >> >>> The degenerate modes of >>> raid0, 5, or 6 are explicit as a possible middle step when converting >>> profiles. We can use a fallback implementation for this case if the >>> accelerated implementations cannot do it. >> >> This is not about a degenerated mode. For a degenerated RAID 6, parity >> generation uses the RAID 5 XOR routines as the second parity will be >> missing. This is about generating two parities for a single data disk, >> which must be explicitly selected. >> > >I think that the David concern is : "what happens for an already >existing btrfs raid6 3 disks filesystem when the user upgrade the kernel ?" >(I am thinking when a new BG needs to be allocated)... > >BR >GB > That's what I'm saying – it should invoke the RAID-1 code under the cover (as with 3 disks, D = P = Q.) _______________________________________________ linux-riscv mailing list [email protected] http://lists.infradead.org/mailman/listinfo/linux-riscv