Conversion from ext4 works really well and is an important step for adoption. After recently converting a large-ish device I noticed dodgy performance, even after defragment & rebalance; noticeably different from the quite good performance of a newly-created btrfs with 16k leaf size, as is the default since recently. So I went spelunking and found that the btrfs-convert logic indeed uses the ext4 block size as leaf size (from #2220): https://git.kernel.org/cgit/linux/kernel/git/mason/btrfs-progs.git/tree/btrfs-convert.c#n2245 This is typically 4096 bytes and explains the observed performance. So while I'm basically familiar with btrfs's design, I know nothing about the details of the conversion (I'm amazed that it works so well, including rollback!) but can/should this not be updated to the new default of 16k, or is there a strong necessary correlation between the ext4 block size and the newly created btrfs? thanks! Holger -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html