I was running some experiments on my 3-node ceph cluster (mounted at /mnt/ceph), and noticed unexpected behavior regarding cephfs set_layout command.
root@varunc-virtual-machine:/mnt/ceph/folder1# touch test3
root@varunc-virtual-machine:/mnt/ceph/folder1# cephfs test3 set_layout -p 3 -s 41943040
root@varunc-virtual-machine:/mnt/ceph/folder1# cephfs test3 show_layout
layout.data_pool: 3
layout.object_size: 41943040
layout.stripe_unit: 4194304
layout.stripe_count: 1
root@varunc-virtual-machine:/mnt/ceph/folder1# vi test3
root@varunc-virtual-machine:/mnt/ceph/folder1# cephfs test3 show_layout
layout.data_pool: 0
layout.object_size: 4194304
layout.stripe_unit: 4194304
layout.stripe_count: 1
I create an empty file and set its layout (which it displays correctly in the corresponding show_layout). Then, I open the file and write something to it (a single line of text), and again use the show_layout command, and it reverts to the default layout. What is the reason for this? Is it that I can not write to the file simply using vi editor? Because when I do the same process again, but instead use cat command to redirect the input into the new file, the layout set by me persists.
root@varunc-virtual-machine:/mnt/ceph/folder1# touch test4
root@varunc-virtual-machine:/mnt/ceph/folder1# cephfs test4 set_layout -p 3 -s 41943040
root@varunc-virtual-machine:/mnt/ceph/folder1# cephfs test4 show_layout
layout.data_pool: 3
layout.object_size: 41943040
layout.stripe_unit: 4194304
layout.stripe_count: 1
root@varunc-virtual-machine:/mnt/ceph/folder1# cat file1.txt > test4
root@varunc-virtual-machine:/mnt/ceph/folder1# cephfs test4 show_layout
layout.data_pool: 3
layout.object_size: 41943040
layout.stripe_unit: 4194304
layout.stripe_count: 1
Also, how do I set the layout for an entire directory. I tried the following:
root@varunc-virtual-machine:/mnt/ceph# cephfs folder2/ set_layout -p 3 -s 4194304
Error setting layout: Invalid argument
root@varunc-virtual-machine:/mnt/ceph# cephfs folder1/ set_layout -p 0 -s 4194304
Error setting layout: Invalid argument
(folder1 contains around 1000 files, folder2 is empty)
Thanks,
Varun_______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
