Is there a way where I can get a list of disk drives of VM's on a specific OSD?
Not directly
Currently I am running the following.
ceph osd map SSD vm-100-disk-0
The above command does not show where the data are stored. To get this more commands have to be run:
Code:
rbd -p <pool> info <virtual-disk>
returns some basic information, note the field block_name_prefix which looks e.g. like "rbd_data.1603ec6b8b4567"
A list about all data objects in the pool can be created by
There will be a huge output, to get the objects assigned to the respective virtual disk select the items containing the above determined block_name_prefix
Afterwards the location where (on which osd) an object is stored can be figured out by
Code:
ceph osd map <pool> <object>
Doing this for each object you will get the OSDs where the virtual disk is stored
Here an example how to do all this comprehensively for one disk:
Code:
rados ls -p SSD | grep `rbd -p SSD info vm-100-disk-0 | grep block | cut -b 21-43` | sed 's/rbd_/ceph osd map SSD rbd_/g' > tempfile;chmod 777 tempfile;./tempfile
But that is when I already know the disk name.
Yes, if you want to get the information for a certain OSD you have to to this for all virtual disks and select the desired OSD.
I want to find out which VM is hogging DIsk IO on the OSD that is currently slugish.
If you have a look at the data for one disk you will probably see that it spread across (almost) all OSDs, therefore your request cannot be fulfilled as you expect. If you have a (too) slow disk remove it simply from your OSDs - its content will be automatically redistributed to the remaining OSDs.
