Re: Free Memory

[Jacob Still <jacobcstill@xxxxxxxxx>]

On Fri, Apr 1, 2022 at 3:04 PM TheBearAK <thebearak@xxxxxxxxx> wrote:
>
> Normally when you type 'free' you get an output that shows:
>
>
>                total        used        free      shared buff/cache
> available
> Mem:     9.3Gi       226Mi       5.5Gi       9.0Mi 3.6Gi       8.9Gi
> Swap:     15Gi          0B        15Gi
>
>
> Where total is the total amount of RAM actually installed in the
> machine.   In this case, this is only showing that 9.3Gi.
>
> Checking with cat /proc/meminfo shows the same 9.3Gb of RAM as the Total.
>
>
> However, checking with "xl info" it shows:
>
> total_memory           : 16356
>
>
> Yesterday the 'free' command was showing that it only had 4 GB of RAM.
> I rebooted the entire server and brought the 4 VMs back online and it
> showed the total to be 16GB again.
>
> Is this normal?   Seems like a big memory leak.    But I'm wondering if
> it could be that I have some bad memory and it keeps mapping it out on
> the fly.
>
>
> I do notice that the VMs get slower and slower over time.  Just
> rebooting everything will clear it up, but it slows down over about 2-3
> months time to the point where ssh to them takes 10-15 seconds to connect.
>
>

You most likely have autobalooning enabled. Try setting autobaloon to
"off" and give
your dom0 a static amount of memory at boot.

See:
https://wiki.xenproject.org/wiki/Xen_Project_Best_Practices#Xen_Project_dom0_dedicated_memory_and_preventing_dom0_memory_ballooning