Regarding btrfs-related defaults for SSD, I opened Bug 1184904 for /etc/sysconfig/btrfsmaintenance defaults. That particular bug is primarily targeting the filesystem corruption seen downstream - probably while live migrating VMs while a balance is running. Setting that value to "none" has stabilized our downstream VMs. Since making that setting, no additional systems have been lost to corrupted btrfs filesystems. Since btrfs balance rewrites a lot of data apparently without much if any benefit on a single disk non-RAID installation, I also like keeping it disabled to reduce wear on SSDs. For the use case of the pet Tumbleweeed VM that runs on my personal laptop, I have it set up an f2fs root filesystem. It's an old Macbook Pro with HDD, so I have the VM running on USB flash (at the under $20 price point, I'm assuming there is no wear leveling)