Proxmox VE Ceph Benchmark 2020/09 - hyper-converged with NVMe

Jesus Blanco

Member
Apr 2, 2018
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As Ceph uses a 4M "block size" I would rather test around changing the NVMe's blocksize from 512K to 4M.
In my Intel SSDPE2KX080T8 NVMe disks I see two LBA format:
LBA Format 0 : Metadata Size: 0 bytes - Data Size: 512 bytes - Relative Performance: 0x2 Good
LBA Format 1 : Metadata Size: 0 bytes - Data Size: 4096 bytes - Relative Performance: 0 Best (in use)

You have wrote 512K to 4M, is that correct or did you mean 512B to 4KB? I can't find anything about 4M LBA Format.

Thanks again!
 
Jan 29, 2019
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In my Intel SSDPE2KX080T8 NVMe disks I see two LBA format:
LBA Format 0 : Metadata Size: 0 bytes - Data Size: 512 bytes - Relative Performance: 0x2 Good
LBA Format 1 : Metadata Size: 0 bytes - Data Size: 4096 bytes - Relative Performance: 0 Best (in use)

You have wrote 512K to 4M, is that correct or did you mean 512B to 4KB? I can't find anything about 4M LBA Format.

Thanks again!
I only found out about msecli from this ZFS benchmark thread and back then had not considered it for my benchmarks.
So yes, I was wrong - it should be 4KB NVMe block size.
And the default Ceph block size is 4MB - no idea if Proxmox does changes to the RBDs here.
 

Alwin Antreich

Active Member
Jan 15, 2021
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antreich.com
So yes, I was wrong - it should be 4KB NVMe block size.
Some NVMe allow to set 4 MB allocation size, not the Micron 9300 though. And it doesn't make any difference if it is 4 KB or 512 B, not with Ceph anyway.

And the default Ceph block size is 4MB - no idea if Proxmox does changes to the RBDs here.
It's vanilla as it gets. You can try to change the stripe size to get better write performance with sacrificing some read performance though.
 

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