Hi, I have problem with CephFS on writing big size file. I have found that my OpenStack Nova backup was not working after I change the rbd based mount of /var/lib/nova/instances/snapshots to CephFS based (mounted on /etc/fstab on all Nova compute nodes). I couldn't relize the cause until I tried to do some test below.
[root@compute-aa instances]# sudo -S -u nova dd if=/dev/zero of=./snapshots/test/test.dat bs=4096 count=1024 1024+0 records in 1024+0 records out 4194304 bytes (4.2 MB) copied, 0.002956 s, 1.4 GB/s It seem that making 4.2MB size file is OK. The "test" folder was been created by nova user too. [root@compute-aa instances]# sudo -S -u nova dd if=/dev/zero of=./snapshots/test/test.dat bs=4096 count=1048576 This test was hang and gave me "D state" of dd process which cannot be killed, so I must reboot that node. This make afraid to do some more test with lower size. When I tried to see the folder content, I found following result. [root@compute-aa ~]# ls -lah /var/lib/nova/instances/snapshots/test/ total 0 drwxr-xr-x 1 nova nova 0 Aug 24 22:35 . drwxr-xr-x 1 nova nova 0 Aug 24 22:33 .. -rw-r--r-- 1 nova nova 0 Aug 24 22:35 test.dat I prefer to use CephFS since the snapshot folder is only for temporary. Please help me to solve this problem. Best regards,
_______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
