Hi Experts, I was trying to test the performance on rbd images. I find the sequential write throughput on cloning image is only harf of that on origin one. I have enabled object-map feature on both images and the cloning image is fully over-written before the performance test. Here is my steps: 1. create two images called "ori-vol1", "ori-vol2" 2. run a "dd" on them to make the images full of data 3. create a snap on "ori-vol1", called "snap-vol1" 4. clone a image from "snap-vol1", called "clone-vol1" 5. run a "dd" on "clone-vol1" to make the image full "copy-up" 6. finally test performance on "ori-vol2" and "clone-vol1". -- sequential write, 64K iosize, fio I have tested on hammer and jewel, the results are similar. Is it expected? I know there may be performance drop on cloning image since the issued object may be at parent image and it required a extra "copy-up" operation. However in my case the objects are all at own image and librbd should have knowledge about this from object-map. Regards Ridge -- 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
