2xm.2 NVME + 2x SSD where to install the system?

[benoitc]

I have 3 machines actually with 2 m.2 NVME disks (256GB) and 2 internals SSD medium endurance (480GB). I have for now installed the system on a raid1 on m.2 disks. I am looking to optmize this installation. Is there anything I could do with such install?

 

[ph0x]

Assumed that these are enterprise grade nvme disks, putting the vm images there could give you a good performance boost. But if you're really experiencing the faster disks also depends on other factors, so it might also not be the big change that you might expect.

 

[benoitc]

Yes. I am not sure it worth any config changes right now. I was thinking maybe to use local disks in a ceph cluster ( I have enough ram). But since disks are internals I am not sure about it since operations during a disk failure will be harder.

 

[ph0x]

I would go for it. The cluster can survive on 2 nodes, so you have time to recover a failed node. I'm heading the same route (just waiting for some disks to arrive) and I think it's okay for home use.
Nvme should have two OSDs per disk though, so maybe 256 GB is a bit small. But that depends on the disk space you need.
Google for ceph calculator from florian.ca there you'll see the safe disk space that results from three nodes ceph cluster.

 

[benoitc]

I would go for it. The cluster can survive on 2 nodes, so you have time to recover a failed node. I'm heading the same route (just waiting for some disks to arrive) and I think it's okay for home use.
Nvme should have two OSDs per disk though, so maybe 256 GB is a bit small. But that depends on the disk space you need.
Google for ceph calculator from florian.ca there you'll see the safe disk space that results from three nodes ceph cluster.

Why 2 OSD per disks?

 

[ph0x]

In order to utilize the massive amount of iops and bandwidth.
See here

 

[benoitc]

In order to utilize the massive amount of iops and bandwidth.
See here

thanks for the link !

 

[ph0x]

You're welcome, good luck!