Howto define OSD weight in Crush map
Hi, after adding an OSD to Ceph it is adviseable to create a relevant entry in Crush map using a weight size depending on disk size. Example: ceph osd crush set osd.<id> <weight> root=default host=<hostname> Question: How is the weight defined depending on disk size? Which algorithm can be used to calculate the weight? From my first Ceph installation (luminous) the Crush map entry for - HDD device with 1.80TB size (output of lsscsi -s): weight was 1.627229 - NVMI device with 3.20TB size (output of lsscsi -s): weight was 2.910889 THX
On 8/30/19 5:01 PM, 74cmonty@gmail.com wrote:
Hi, after adding an OSD to Ceph it is adviseable to create a relevant entry in Crush map using a weight size depending on disk size.
Example: ceph osd crush set osd.<id> <weight> root=default host=<hostname>
Question: How is the weight defined depending on disk size? Which algorithm can be used to calculate the weight?
From my first Ceph installation (luminous) the Crush map entry for - HDD device with 1.80TB size (output of lsscsi -s): weight was 1.627229 - NVMI device with 3.20TB size (output of lsscsi -s): weight was 2.910889
Actually you can define "human readable" value. HDD 1.80TB is a 2TB for human. So you can declare this weight as "2.0". k
participants (2)
-
74cmonty＠gmail.com
-
Konstantin Shalygin