I realize we're probably kind of pushing it. It was the only option i
could think of however that would satisfy the idea that:
Have separate servers for HDD and NVMe storage spread out in 3 data centers.
Always select 1 NVMe and 2 HDD, in separate data centers (make sure NVMe
is primary)
If on
CRUSH is a pseudorandom, probabilistic algorithm. That can lead to problems
with extreme input.
In this case, you've given it a bucket in which one child contains ~3.3% of
the total weight, and there are only three weights. So on only 3% of
"draws", as it tries to choose a child bucket to descend
We kind of turned the crushmap inside out a little bit.
Instead of the traditional "for 1 PG, select OSDs from 3 separate data
centers" we did "force selection from only one datacenter (out of 3) and
leave enough options only to make sure precisely 1 SSD and 2 HDD are
selected".
We then orga
Yes.
It is a hybrid solution where a placement group is always located on one
NVMe drive and two HDD drives. Advantage is great read performance and
cost savings. Disadvantages is low write performance. Still the write
performance is good thanks to rockdb on Intel Optane disks in HDD servers.
On 01/29/2018 01:14 PM, Niklas wrote:
Ceph luminous 12.2.2
$: ceph osd pool create hybrid 1024 1024 replicated hybrid
$: ceph -s
cluster:
id: e07f568d-056c-4e01-9292-732c64ab4f8e
health: HEALTH_WARN
Degraded data redundancy: 431 pgs unclean, 431 pgs
degraded, 431
Ceph luminous 12.2.2
$: ceph osd pool create hybrid 1024 1024 replicated hybrid
$: ceph -s
cluster:
id: e07f568d-056c-4e01-9292-732c64ab4f8e
health: HEALTH_WARN
Degraded data redundancy: 431 pgs unclean, 431 pgs
degraded, 431 pgs undersized
services:
mon: 3 daemo
