1 Commits

Author	SHA1	Message	Date
David Teigland	904e1e3d26	Place the first PE at 1 MiB for all defaults ... . When using default settings, this commit should change nothing. The first PE continues to be placed at 1 MiB resulting in a metadata area size of 1020 KiB (for 4K page sizes; slightly smaller for larger page sizes.) . When default_data_alignment is disabled in lvm.conf, align pe_start at 1 MiB, based on a default metadata area size that adapts to the page size. Previously, disabling this option would result in mda_size that was too small for common use, and produced a 64 KiB aligned pe_start. . Customized pe_start and mda_size values continue to be set as before in lvm.conf and command line. . Remove the configure option for setting default_data_alignment at build time. . Improve alignment related option descriptions. . Add section about alignment to pvcreate man page. Previously, DEFAULT_PVMETADATASIZE was 255 sectors. However, the fact that the config setting named "default_data_alignment" has a default value of 1 (MiB) meant that DEFAULT_PVMETADATASIZE was having no effect. The metadata area size is the space between the start of the metadata area (page size offset from the start of the device) and the first PE (1 MiB by default due to default_data_alignment 1.) The result is a 1020 KiB metadata area on machines with 4KiB page size (1024 KiB - 4 KiB), and smaller on machines with larger page size. If default_data_alignment was set to 0 (disabled), then DEFAULT_PVMETADATASIZE 255 would take effect, and produce a metadata area that was 188 KiB and pe_start of 192 KiB. This was too small for common use. This is fixed by making the default metadata area size a computed value that matches the value produced by default_data_alignment.	2018-11-26 16:36:50 -06:00