Hi,
I was experimenting with Ceph and found an interesting behavior (at
least to me) : Number of objects doubled when a new placement group was
added.
Experiment Set Up:
- 3 Nodes with one OSD per node
- Replication = 1
- ceph osd pool create $poolName 1;
- ceph osd pool set $poolName size 1;
- Set number of PG=30
- ceph osd pool set $poolName pg_num 30;
- ceph osd pool set $poolName pgp_num 30
- Start creating objects of 1000 Bytes for a period of 120 seconds using
rados bench with 1 thread
- rados -p $poolName -b 1000 -t 1 bench 120 write &> bench.out
- While the creation is going on gather df statistics every second
- rados df -p $poolName &> df.out
- After 75 seconds add a new placement group
- ceph osd pool set $poolName pg_num 31;
- ceph osd pool set $poolName pgp_num 31;
- Plot the number of objects and data size from the above df command.
I was wondering why the number of object count doubled when we add an new
placement group.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ceph.com/pipermail/ceph-users-ceph.com/attachments/20140514/2ff04930/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: object_increase.png
Type: image/png
Size: 7022 bytes
Desc: not available
URL: <http://lists.ceph.com/pipermail/ceph-users-ceph.com/attachments/20140514/2ff04930/attachment.png>
