Hello, Whilst testing Ceph 0.94.1 on 64-bit ARM hardware, I noticed that switching the kernel PAGE_SIZE from 4KB to 64KB caused an increase by a factor of ~6 in the total amount of data written to disk (according to blktrace) by the OSD when running the RBD bench-write test (with --io-pattern rand, --io-size=4096, --num-threads=16, --io-total=$((50 << 20))). Delving into the source, it is apparent that the FileJournal code uses the current page size for the block size. I was wondering why something like the block device sector size wasn't used instead? Is there a mmap somewhere that I missed, or are fewer larger blocks better for most use cases? (The use case above may be overly contrived?). Cheers, -- Steve -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
