Ceph storage mix SSD and HDD

[Static]

Good afternoon, colleagues!

I have a problem with the implementation of Ceph storage.
My configuration:
There is a Supermicro Superblade chassis, which has 20 physical servers. Each server has 2 processors, 64 GB of RAM, 1xSDD 32GB for OS, 1xSSD and 1xHDD for Ceph
There is a desire to collect Ceph storage.
Installed ProxmoxVE 5.2
How best to build Ceph?
1) SSD pool and HDD pool?
2) SSD pool and HDD with journals on SSD? It's real?
3) Any other configuration?

How many disks to collect in the pool? 20? Or split into multiple pools with fewer drives?

Thanks in advance, experience in using Ceph is not great.

 

[AlexLup]

SSD cache pool for me did wonders, but I also have journals on separate SSD's. Followed the guide here: http://technik.blogs.nde.ag/2017/07/14/ceph-caching-for-image-pools/

You should also consider upgrading the network to a 10gb. And all disks should be in the pool as more disks = faster speeds since the placement groups gets spread out so more disks get to read/write. Consider using the ceph pg calculator on the ceph page to make the best decision there, as again, more PGs = more RAM but faster storage..

 

[sg90]

What size is the SSD and HD in each server?
What's the end goal for CEPH, slow cold storage, or will you be running VM's with SQL that require low latency high IOPS?
Will you be running VM's on the same hardware as the OSD or will each server be just running OS + OSD's?