CPU usage breakdown?

[rmdes]

I keep having this drop_caches process eating all my CPU

I tried to kill this process but no matter the way I choose to terminate/kill it it just keeps going, something is occupying the system,it seems to me, outside of the docker environnement.

[rmdes]

@nebulon running apps are not the problem, what I see is high CPU usage at the / root level of the box

[nebulon]

Ok this is interesting, according to https://linux-mm.org/Drop_Caches this means the system tries to free up memory pages. And this essentially from time to time.
From Cloudron side we do not actively do this at all, so this is likely Ubuntu behavior. If this takes up a lot of cpu and for longer time periods, this may be related to the system I/O performance as such.

I have to read up further though, for example is this is swap related and then it will indeed be painful if the swap is on some slow disk.

[rmdes]

After last reboot,the process is now gone and CPU is more stable, quite crazy how this process completely freeze the cloudron box, Swap is being used at 338M over 4GB available and seem to increase very slowly, CPU is now around 50% more or less, still with Highs of 89%

i guess it will be better when on Ubuntu 20.x ? and moving to a new VPS or VDS soon probably

[nebulon]

Not sure if Ubuntu 20.04 will change anything here, this seems to be a pretty normal thing since a long time for linux distros.

Also this may not indicate that you need more main memory or so, it might simply mean that the process of discarding and finding those resources takes long on your system. Thus my concern about system I/O speeds.

Which VPS provider are you currently using and is this an SSD system?

[rmdes]

@nebulon This is the VPS specs I'm using : https://contabo.com/?show=configurator&vserver_id=237
8 CPU cores
30 GB RAM (guaranteed)
800 GB disk space (100% SSD)
100% SSD disk space

[nebulon]

This looks ok and good enough to me. I am always a bit unsure about disk I/O measurements and also if this is the root cause here at all, but anyways maybe you can do some sanity check with hdparm -t /dev/vda1 (replace /dev/vda1 with you main disk partition)

It should be somewhere above 500MB/s at least on provider with SSD in my experience.

[ruihildt]

FYI, CPU usage is now stable and around 13%, more or less since Contabo did, and I quote their email, a "technical adjustement".

You can clearly see on that monthly CPU chart, how it evolved (granted it's early days, but still):

Not only this, but the dashboard now loads nearly instantly whereas beforehand, it could take up to 30 seconds.

Taking into account previous random issues with cheaper Contabo VPS in the past, I tend to think the issue was from Contabo from the start.

[robi]

@ruihildt
nice to see it resolved outside of Cloudron.

If you want a similarly sized and less expensive system, I can share an invite link for ssd nodes that's been working well for us.

[ruihildt]

@robi Yes please.

I also think next time I encounter a stability issue, I'll explore the provider angle sooner, maybe by replicating it elsewhere the same stack.

[p44]

Hello all, I've a similar problem and I want to ask you what can be the source causes coming from provider.

I'm running a Cloudron instance on a bare metal machine on Hetzner, and I get constantly CPU under 40-50%.

Let me know if I have to open a new post or keep continuing on this.

[nebulon]

@p44 is the htop output similar or some other app/process causing the cpu usage?

[p44]

Hello @nebulon,

I did systemd-cgtop and the result is this:

Then, from Cloudron control panel, the output is this:

Just few months ago, CPU it was stable to 1-2% in the not working hours time.

Now it seems to be little bit increased, so I was asking myself if this problem was related to Cloudron or to provider (Hetzner).

[jonslab]

I seem to be having a similar issue. None of the apps in cloudron are using enough cpu to even show up here, but I am constantly needing to reboot the cloudron vm to get the cpu usage to drop back down to normal levels.

Not sure if you can tell from the graph, but I've needed to reboot it 3 times in the last month because apps become unresponsive whenever this happens.

htop won't help now because it was just rebooted yesterday and everything seems to be running smoothly.
Does anyone have any suggestions on how to find out why this is happening, or how to find out the cause?

[p44]

@nebulon Hello Nebulon, any suggestion about this point?

[girish]

@jonslab just to double check, so the server has 12 cores?

[p44]

@girish «The PX62-NVMe Dedicated Root Server is the perfect choice for people who have a need for speed, and also want reliability. This model features a powerful Intel Xeon E-2176G hexa-core processor with Hyper-Threading technology based on Coffee Lake architecture».

[girish]

@p44 per your cgtop output something is using 47.4%. Are you able to identify the process using top or htop?

[p44]

@girish now I've this: