Disable overlayfs features not used by Docker #2773
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Currently `CONFIG_OVERLAY_FS_METACOPY` and `CONFIG_OVERLAY_FS_REDIRECT_DIR` kernel options are enabled but not preferred by Docker. The metadata copy feature is disabled by default, and also not actively used by the overlayfs2 driver (see moby/moby@2c3d1f7). So the metadata copy config is not really problematic per se. However, it enables the redirect_dir feature. And a kernel which has the redirect_dir feature compiled in also enables it by default. This actually makes the overlayfs2 driver to fallback to naive diff, which is, from what I understand, slower than the overlayfs native diff (see also moby/moby@49c3a7c). The Docker daemon is also reporting this on startup: Not using native diff for overlay2, this may cause degraded performance for building images: kernel has CONFIG_OVERLAY_FS_REDIRECT_DIR enabled Currently `CONFIG_OVERLAY_FS_METACOPY` is enabled, and it also enables `CONFIG_OVERLAY_FS_REDIRECT_DIR`. There was already a previous attempt to disable the latter (see home-assistant#2067). Disable both configs explicitly until Docker is able to use them.
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Currently
CONFIG_OVERLAY_FS_METACOPYandCONFIG_OVERLAY_FS_REDIRECT_DIRkernel options are enabled but not preferred by Docker. The metadata copy feature is disabled by default, and also not actively used by the overlayfs2 driver (see moby/moby@2c3d1f7). So the metadata copy config is not really problematic per se. However, it enables the redirect_dir feature. And a kernel which has the redirect_dir feature compiled in also enables it by default. This actually makes the overlayfs2 driver to fallback to naive diff, which is, from what I understand, slower than the overlayfs native diff (see also moby/moby@49c3a7c). The Docker daemon is also reporting this on startup:Currently
CONFIG_OVERLAY_FS_METACOPYis enabled, and it also enablesCONFIG_OVERLAY_FS_REDIRECT_DIR. There was already a previous attempt to disable the latter (see #2067).Disable both configs explicitly until Docker is able to use them.