[Users] Difference between swap and swappages?

[Kirill Kolyshkin]

On Tue, 10 Dec 2019 at 11:30, Arjit Chaudhary <arjit.c at gmail.com> wrote:

> Hi,
> Aha so they're the same thing, was just curious as I've been noticing a
> bit of odd behavior on OpenVZ 7 host-nodes where the node has 128G RAM,
> around 30G used and it's swapping out 12G still instead of using the RAM as
> vSwap. Swappiness is set to 10 as well.
>

Is it for containers or the host? You can use vzubc to check it.

In general, it's normal for some swappiness to occur even in case there's
enough free RAM, but I agree that the figure of 12G looks a bit too big.


>
> I'm using the following commands to build the container if that help,
>
> /usr/sbin/vzctl create $VMID --ostemplate $DISTRO
> /usr/sbin/vzctl set $VMID --ipadd $VPS_IP --save
> /usr/sbin/vzctl set $VMID --hostname vps.server.com --save
> /usr/sbin/vzctl set $VMID --nameserver 8.8.8.8 --save
> /usr/sbin/vzctl set $VMID --diskspace
> $DISK_SPACE$DISK_VARIABLE:$DISK_SPACE$DISK_VARIABLE --save
> /usr/sbin/vzctl set $VMID --ram $RAM$RAM_VARIABLE --swappages
> $SWAP$SWAP_VARIABLE --save
>
>
Again, please read the man page and use --swap not --swappages. If you're
so inclined to use --swappages, please do it in a correct manner (barrier
should be set to 0 as described).


>
>
> On Wed, Dec 11, 2019 at 12:51 AM Kirill Kolyshkin <kolyshkin at gmail.com>
> wrote:
>
>> On Tue, 10 Dec 2019 at 10:42, Arjit Chaudhary <arjit.c at gmail.com> wrote:
>>
>>> Hi,
>>> Is there any difference between setting vSwap on the OpenVZ 7 based
>>> virtual machine?
>>>
>>> vzctl set $VMID --ram $RAM --swap $SWAP --save
>>>
>>> vs
>>>
>>> vzctl set $VMID --ram $RAM --swappages $SWAP --save
>>>
>>>
>>> does --swap end up using real swap on the host-node
>>>
>>> and
>>>
>>>  --swappages use the RAM as swap (ie, vswap) ?
>>>
>>>
>>> or are both the same ?
>>>
>>
>> Please take a look at vzctl man page, it's all described in there. In
>> short, you should use --swap;
>> --swappages is working but obsolete.
>>
>>
>> _______________________________________________
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>> Users at openvz.org
>> https://lists.openvz.org/mailman/listinfo/users
>>
>
>
> --
> Thanks,
> Arjit Chaudhary
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> https://lists.openvz.org/mailman/listinfo/users
>
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