On Mon, Feb 03, 2025 at 08:04:42AM +0000, Johannes Thumshirn wrote: > Well for the WAF part, it'll save us 32 Bytes per FS sector (typically > 4k) in the btrfs case, that's ~0.8% of the space. It saves you from the cascading btree updates. With nocow this could actually allow btrfs to write with WAF=1 for pure overwrites. But even with data cow it will reduce a lot of churn, especially for O_SYNC writes.
