20.05.2016 20:59, Austin S. Hemmelgarn пишет: > On 2016-05-20 13:02, Ferry Toth wrote: >> We have 4 1TB drives in MBR, 1MB free at the beginning, grub on all 4, >> then 8GB swap, then all the rest btrfs (no LVM used). The 4 btrfs >> partitions are in the same pool, which is in btrfs RAID10 format. /boot >> is in subvolume @boot. > If you have GRUB installed on all 4, then you don't actually have the > full 2047 sectors between the MBR and the partition free, as GRUB is > embedded in that space. I forget exactly how much space it takes up, > but I know it's not the whole 1023.5K I would not suggest risking usage > of the final 8k there though.
If you mean grub2, required space is variable and depends on where /boot/grub is located (i.e. which drivers it needs to access it). Assuming plain btrfs on legacy BIOS MBR, required space is around 40-50KB. Note that grub2 detects some post-MBR gap software signatures and skips over them (space need not be contiguous). It is entirely possible to add bcache detection if enough demand exists. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
