It is not always easy to know how to organize your data in the Crushmap, especially when trying to distribute the data geographically while separating different types of discs, eg SATA, SAS and SSD. Let's see what we can imagine as Crushmap hierarchy.
Take a simple example of a distribution …
Ceph makes it easy to create multiple cluster on the same hardware with the naming of clusters. If you want a better insolation you can use LXC, for example to allow a different version of Ceph between your clusters.
For this you will need access to the physical disks from …
Since Firefly you can test the use of the lightweight web client Civetweb instead of Apache. To activate it, it's very simple, there's nothing to install again, simply add this line to your ceph.conf:
[client.radosgw.gateway]
rgw frontends = "civetweb port=80"
...
If you have already installed apache, remember …
From Gregory and Craig in mailing list...
Gregory Farnum http://lists.ceph.com/pipermail/ceph-users-ceph.com/2014-June/040961.html %} "ceph osd crush reweight" sets the CRUSH weight of the OSD. This weight is an arbitrary value (generally the size of the disk in TB or something) and controls how much …
Realtime :
mount -o discard /dev/rbd0 /mnt/myrbd
Using batch :
fstrim /mnt/myrbd
The empty FS :
$ rbd create rbd/myrbd --size=20480
$ mkfs.xfs /dev/rbd0
$ rbd diff rbd/myrbd | awk '{ SUM += $2 } END { print SUM/1024/1024 " MB" }'
14.4062 MB
With a big file... :
$ mount /dev/rbd0 …