> Where does the win come from with "directI/O"? Is it 1), 2), or some > combination? If its a combination, what's the percentage of each > towards the win? > That will vary based on workload (I know, you already knew that ... :^). Decomposing the performance win between what is gained as a result of single writer lock breakup and no caching is something we can only guess at, because, at least for UFS, you can't do just one - it's all or nothing. > We need to tease 1) and 2) apart to have a full understanding.
We can't. We can only guess (for UFS). My opinion - it's a must-have for ZFS if we're going to get serious attention in the database space. I'll bet dollars-to-donuts that, over the next several years, we'll burn many tens-of-millions of dollars on customer support escalations that come down to memory utilization issues and contention between database specific buffering and the ARC. This is entirely my opinion (not that of Sun), and I've been wrong before. Thanks, /jim _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
