Hi, As I have been reading btrfs whitepaper it speaks about autodefrag in very generic terms - once random write in the file is detected it is put in the queue to be defragmented. Yet I could not find any specifics about this process described anywhere.
My use case is databases and as such large files (100GB+) so my questions are - is my understanding what defrag queue is based on files not parts of files which got fragmented correct ? - Is single random write is enough to schedule file for defrag or is there some more elaborate math to consider file fragmented and needing optimization ? - Is this queue FIFO or is it priority queue where files in more need of fragmentation jump in front (or is there some other mechanics ? - Will file to be attempted to be defragmented completely or does defrag focuses on the most fragmented areas of the file first ? - Is there any way to view this defrag queue ? - How are resources allocated to background autodefrag vs resources serving foreground user load are controlled - What are space requirements for defrag ? is it required for the space to be available for complete file copy or is it not required ? - Can defrag handle file which is being constantly written to or is it based on the concept what file should be idle for some time and when it is going to be defragmented Let me know if you have any information on these -- Peter Zaitsev, CEO, Percona Tel: +1 888 401 3401 ext 7360 Skype: peter_zaitsev -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
