We are going to in the next days, waiting for arrival...
There is no newer one, we already checked that a while ago during investigations
That would be sooo nice :S
Thx
Yes, we already postet this early:
I would be completely with you. But as we assumes sth. like that too, we freed the NVMEs, removed /wiped them from ceph and - at the moment - just added the 2TB ones back to ceph. So IMHO they are now completely empty, but the fio tests are as bad as...
Another question: What about network latencies? We found this:
https://www.cubewerk.de/2020/10/23/ceph-performance-guide-2020-for-ssd-nvme/
There one can read:
What can affect the overall performance of a ceph-cluster?
Slow network (latency!), bad/slow disks, lack of CPU-cycles.
[...]
ping -c...
Yep, fingers crossed... It's really frustrating, as we are searching for the root cause for some weeks now and didn't really get hands on it till today... and so many contradictory facts / situations... o_O
Nope, as described in the first post it is not just one homeserver but a productive 3 - Node Proxmox / Ceph cluster, running ~30 VMs on it partly used by customers, so reinstalling from scratch would really be "suboptimal"
The Cluster is running for a longer time now with this configuration and...
@ITT
We have ordered 3 Enterprise NVMes each 1TB in size and now hoping the best....
And yes, we set the MTU to 9000
But - sorry for coming back to this thoughts again - I'm really not sure if something else is going completely wrong in the cluster and this "consumer nvmes are bad" - thing of...
So here the missing Infos:
Adapter Cards of this kind:
https://www.amazon.de/Adapter-K%C3%BChlk%C3%B6rper-6amLifestyle-Adapterkarte-Support/dp/B07RZZ3TJG/ref=sr_1_3?keywords=pcie+nvme+adapter&qid=1673986009&sprefix=pcie%2Caps%2C196&sr=8-3
PCIe Slots they are running in:
Last but not least for completing the whole picture:
fio write test of a VM Disk using Ceph Pool with the HDD SAS Disks as Storage:
--> IOPS=7, BW=31.9KiB/s, lat=125.31ms
IMHO bad values even for SAS HDDs, isn't it?
Which again leads us to the assumption, that there is sth. wrong more...
When setting the VM Disk Cache from "No cache" to "Write Back" things even get worse:
--> IOPS=74, BW=297KiB/s, lat=13.5ms
We thought, "Write Back" would increase write performance... everything very confusing...
In the meantime we benchmarked a VM Disk using the NVMe Ceph Pool inside our Debian Testing VM with fio, and are a little bit surprised:
#fio --ioengine=psync --filename=/dev/sdb --size=9G --time_based --name=fio --group_reporting --runtime=600 --direct=1 --sync=1 --rw=write --bs=4K...
Infos arn't missing, given here (https://forum.proxmox.com/threads/vm-i-o-performance-with-ceph-storage.120929/post-526311)
-> The disks are those:
Crucial P2 CT1000P2SSD8 (1TB)
Crucial P2 CT2000P2SSD8 (2TB)
Connected via PCIe Adapter Card to PCIe 4x Slots
Here the first benchmarking results:
1.) FIO on NVMEs (all have similar values, no matter if 1TB or 2TB):
# fio --ioengine=libaio --filename=/dev/nvme2n1 --direct=1 --sync=1 --rw=write --bs=4K --numjobs=1 --iodepth=1 --runtime=60 --time_based --name=fio
fio: (g=0): rw=write, bs=(R) 4096B-4096B...
@stepei: you anticipated our current questions which are going in exact the same direction :D
Actually we are going through the Links / PDF from @shanreich's last post and wondering if it is really necessary for ceph to have enterprise SSD/NVMe which costs >1K€ per piece (the PDF is dated...
@Neobin
Thx for your hints... in the meanwhile we also came across the fact that it is not the best idea to use consumer NVMes for ceph when it comes to performance, so far, so good...
BUT: is it really realistic that the VM I/O performance (and notice: just when writing small files) when...
OK, then we will give it a try over night..
BTW: Just stumbled across this:
https://github.com/rook/rook/issues/6964
There the Option "bdev_async_discard" beside "bdev_enable_discard" is mentioned and also set to "true". When being set to false in combination with "bdev_enable_discard" enabled...
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