On Sat, 10 Mar 2018 16:50:22 +0100 Adam Borowski <kilobyte@xxxxxxxxxx> wrote: > Since we're on a btrfs mailing list, if you use qemu, you really want > sparse format:raw instead of qcow2 or preallocated raw. This also works > great with TRIM. Agreed, that's why I use RAW. QCOW2 would add a second layer of COW on top of Btrfs, which sounds like a nightmare. Even if you would run those files as NOCOW in Btrfs, somehow I feel FS-native COW is more efficient than emulating it in userspace with special format files. > > It works, just not with some of the QEMU virtualized disk device drivers. > > You don't need to use qemu-img to manually dig holes either, it's all > > automatic. > > It works only with scsi and virtio-scsi drivers. Most qemu setups use > either ide (ouch!) or virtio-blk. It works with IDE as well. -- With respect, Roman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
