High memory usage

[da-alb]

Hi,

I have a host with roughly 90 LXCs and 50 KVMs running. I've calculated the total usage and roughly it's something around 100 GiB, the host has 384 GiB of total ram installed.

I'm having some difficulties on understanding what's happening. After host reboot the total usage seems to be around 100 GiB. I suspect using PBS as a backup method as something to do this issue.



Any ideas?

Thanks

 

[birdy]

If you're using ZFS, this will "eat" up to 50% of your memory.

 

[da-alb]

If you're using ZFS, this will "eat" up to 50% of your memory.

I have roughly 2/2 TiB of zfs. I don't think it uses 200 GiB for only 2/3 TiB

 

[birdy]

Only one way to find out:

arc_summary

 

[da-alb]

Only one way to find out:

arc_summary

Thanks for pointing that out. I totaly forgot about it. Arc size (current) is using half of the total ram. I'm going to reconfigure it, I have a very small pool in mirror mode.

Thanks

 

[birdy]

I don't think it uses......

My signature is chosen with a reason.

Glad I could be of help.

 

[da-alb]

My signature is chosen with a reason.

Glad I could be of help.

You're right, thanks again!

 

[LnxBil]

View attachment 32926

Any ideas?

Some of you LX(C) containers use swap instead of RAM, so give them more RAM. Your system is unnecessarily slow because of this. You have ~60 GB free but all swap used? That is a configuration error and has nothing to do with ZFS.

 

[da-alb]

Some of you LX(C) containers use swap instead of RAM, so give them more RAM. Your system is unnecessarily slow because of this. You have ~60 GB free but all swap used? That is a configuration error and has nothing to do with ZFS.

The containers are not swapping, they have more than enough ram, in fact they are only using 400 MBs each and they have 1 or 2 GB each...

 

[LnxBil]

The containers are not swapping, they have more than enough ram, in fact they are only using 400 MBs each and they have 1 or 2 GB each...

Then there is something seriously wrong with your setup and you need to investigate further.

 

[da-alb]

Then there is something seriously wrong with your setup and you need to investigate further.

As written above, arc is the cause...

 

[Dunuin]

But your SWAP is at 100% usage (8191 of 8191 MB) so something is swapping while you still got 61GB RAM available.
You could try to lower the swappiness down to 1, so it is really only used to prevent the OOM killer from triggering.

 

[da-alb]

But your SWAP is at 100% usage (8191 of 8191 MB) so something is swapping while you still got 61GB RAM available.
You could try to lower the swappiness down to 1, so it is really only used to prevent the OOM killer from triggering.

I'll try

 

[LnxBil]

As written above, arc is the cause...

No it's not. What @Dunuin said.

 

[da-alb]

No it's not. What @Dunuin said.

I'll look into both things then. Thanks

 

[da-alb]

Lowering the arc size cache to a limit of 8 GB the ram usage is now normal. Thank you all

 

[da-alb]

We can close the thread, thanks!