Forgot to mention: Each file is zero byte. And the available of memory is limited to 512 MB. Best, Kai On Mar 5, 2012, at 9:16 PM, Kai Ren wrote: > I've run a little wired benchmark on comparing Btrfs v0.19 and XFS: > > There are 2000 directories and each directory contains 1000 files. > The workload randomly stat a file or chmod a file for 2000000 times. > And the number of stat and chmod are 50% and 50%. > > I monitor the number of disk read requests > > #Disk Write Requests, #Disk Read Requests, #Disk Write Sectors, #Disk Read Sectors > Btrfs 2403520 1571183 29249216 13512248 > XFS 625493 396080 10302718 4932800 > > I found the number of write quests of Btrfs is significant larger than XFS. > I am not quite familiar with how btrfs commits the metadata change into the disks. > From the website, it is said that btrfs uses COW B-tree which never overwrite previous disk pages. > I assume that Btrfs also keep an in-memory buffer to keep the metadata changes. > But it is unclear to me that how often Btrfs will commit these changes and what is the behind mechanism. > > Could anyone please comment on the experiment results and give a brief explanation of Btrfs's metadata committing mechanism? > > Sincerely, > > Kai Ren -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
