On 11/21/19 4:25 PM, Sage Weil wrote:
Adding dev@xxxxxxx
On Thu, 21 Nov 2019, Muhammad Ahmad wrote:
While trying to research how crush maps are used/modified I stumbled
upon these device classes.
https://ceph.io/community/new-luminous-crush-device-classes/
I wanted to highlight that having nvme as a separate class will
eventually break and should be removed.
There is already a push within the industry to consolidate future
command sets and NVMe will likely be it. In other words, NVMe HDDs are
not too far off. In fact, the recent October OCP F2F discussed this
topic in detail.
If the classification is based on performance then command set
(SATA/SAS/NVMe) is probably not the right classification.
I opened a PR that does this:
https://github.com/ceph/ceph/pull/31796
I can't remember seeing 'nvme' as a device class on any real cluster; the
exceptoin is my basement one, and I think the only reason it ended up that
way was because I deployed bluestore *very* early on (with ceph-disk) and
the is_nvme() detection helper doesn't work with LVM. That's my theory at
least.. can anybody with bluestore on NVMe devices confirm? Does anybody
see class 'nvme' devices in their cluster?
Thanks!
sage
Here's what we've got on the new performance nodes with Intel NVMe drives:
ID CLASS WEIGHT TYPE NAME
-1 64.00000 root default
-3 64.00000 rack localrack
-2 8.00000 host o03
0 ssd 1.00000 osd.0
1 ssd 1.00000 osd.1
2 ssd 1.00000 osd.2
3 ssd 1.00000 osd.3
4 ssd 1.00000 osd.4
5 ssd 1.00000 osd.5
6 ssd 1.00000 osd.6
7 ssd 1.00000 osd.7
Mark
