On Sat, Sep 02, 2017 at 03:41:42PM -0700, Richard Wareing wrote: > - Replaced rtdefault with rtdisable, this yields similar operational > benefits when combined with the existing mkfs time setting of the inheritance > flag on the root directory. Allows temporary disabling of real-time allocation > without having to walk entire FS to remove flags (which could be time consuming). > I still don't think it's super obvious to an admin the real-time flag was put > there at mkfs time (vs. rtdefault being in mount flags), but this gets me > half of what I'm after. I still don't understand this option. What is the use case of dynamically switching on/off these default to the rt device? > - rtfallocmin no changes, need to think more about this. Still a pretty big > fan of this option for reasons already stated; at least until a more elegant > solution such as preferred AGs (we'd need a tunable size for the "preferred" > AG, since our SSD partitions are a fraction of the size of a normal AG) can > be implemented. The only other idea I have is to make a new ioctl e.g. > "norealtime", which causes the RT bits to stay cleared regardless of > inheritance bits on the containing directory. This would allowing the > "steering" of files to the data device (e.g. SSD); this is probably a safer > design than defaulting to SSD and steering to the HDD via the realtime ioctl. Jens just added a nice new fcntl to declare the life time of write streams (and in theory can add other I/O hints). How about a a mount option that moves all I/O with a given hint to the RT device? E.g. rt=longlife would direct I/O on a file with an rw hint of RWH_WRITE_LIFE_LONG or RWH_WRITE_LIFE_EXTREME to the RT subvolume as long as there aren't any previous extents. -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
