I might have missed something in the question.
It is meant to let the block device know about all of the space unused by the file system.
Regards,
Ric
On Jan 29, 2018 11:56 AM, "Wido den Hollander" <wido@xxxxxxxx> wrote:
On 01/29/2018 12:29 PM, Nathan Harper wrote:
Hi,
I don't know if this is strictly a Ceph issue, but hoping someone will be able to shed some light. We have an Openstack environment (Ocata) backed onto a Jewel cluster.
We recently ran into some issues with full OSDs but couldn't work out what was filling up the pools.
It appears that fstrim isn't actually working (or being ignored) within the instances:
[centos@with ~]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 8.0G 1.2G 6.9G 14% /
plenty of unused space that can be reclaimed:
running fstrim:
[centos@with ~]$ sudo fstrim -a -v
/: 6.9 GiB (7416942592 bytes) trimmed
however, running the command again:
[centos@with ~]$ sudo fstrim -a -v
/: 6.9 GiB (7416942592 bytes) trimmed
It depends on the FS you use inside the VM.
iirc XFS will always tell you the total free space of the FS being trimmed and ext4 only the actual bytes which are trimmed.
The discard option was enabled following:
https://ceph.com/geen-categorie/openstack-and-ceph-rbd- discard/
Have I missed anything at the Ceph layer to enable this? Is there anything I can do to see if the request is making it's way through to the Ceph layer?
Try using 'rbd du' and see if it makes a difference.
You also want to check if the XML definition of libvirt has unmap enabled although I expect it does since you don't see any errors.
Wido
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