Thanks.  I tried the ksm_preload option but it does not seem to work.  As I 
mentioned below, I had to creat the ksm_preload and ksm-wrapper tools manually 
since I could not find them in the “normal” Ubuntu repositories.

Does anyone know if the ksm_preload libraries are native to Ubuntu (CentOS 
calls it the "ksm_preload-0.10-3.el6.x86_64.rpm” package)?







> On Jun 4, 2017, at 9:18 PM, Tomasz Chmielewski <[email protected]> wrote:
> 
> KSM only works with applications which support it:
> 
>     KSM only operates on those areas of address space which an application 
> has advised to be likely candidates
>     for merging, by using the madvise(2) system call: int madvise(addr, 
> length, MADV_MERGEABLE.
> 
> This means that doing:
> 
>    echo 1 > /sys/kernel/mm/ksm/run
> 
> will be enough for KVM, but will not do anything for applications like bash, 
> nginx, apache, php-fpm and so on.
> 
> 
> Please refer to "Enabling memory deduplication libraries in containers" on 
> https://openvz.org/KSM_(kernel_same-page_merging) - you will have to use 
> ksm_preload mentioned. I haven't personally used it with LXD.
> 
> 
> Tomasz Chmielewski
> https://lxadm.com
> 
> 
> On Monday, June 05, 2017 09:48 JST, Ron Kelley <[email protected]> wrote: 
> 
>> Thanks Fajar. 
>> 
>> This is on-site with our own physical servers, storage, etc.  The goal is to 
>> get the most containers per server as possible.  While our servers have lots 
>> of RAM, we need to come up with a long-term scaling plan and hope KSM can 
>> help us scale beyond the standard numbers.
>> 
>> As for the openvz link; I read that a few times but I don’t get any positive 
>> results using those methods.  This leads me to believe (a) LXD does not 
>> support KSM or (b) the applications are not registering w/the KSM part of 
>> the kernel.
>> 
>> I am going to run through some tests this week to see if I can get KSM 
>> working outside the LXD environment then try to replicate the same tests 
>> inside LXD.
>> 
>> Thanks again for the feedback.
>> 
>> 
>> 
>>> On Jun 4, 2017, at 6:15 PM, Fajar A. Nugraha <[email protected]> wrote:
>>> 
>>> On Sun, Jun 4, 2017 at 11:16 PM, Ron Kelley <[email protected]> wrote:
>>> (Reviving the thread about Container Scaling:  
>>> https://lists.linuxcontainers.org/pipermail/lxc-users/2016-May/011607.html)
>>> 
>>> We have hit critical mass with LXD 2.12 and I need to get Kernel Samepage 
>>> Merging (KSM) working as soon as possible.  All my research has come to a 
>>> dead-end, and I am reaching out to the group at large for suggestions.
>>> 
>>> Background: We have 5 host servers - each running U16.04 
>>> (4.4.0-57-generic), 8G RAM, 20G SWAP, and 50 containers (exact configs per 
>>> server - nginx and php 7).
>>> 
>>> 
>>> Is this a cloud, or on-site setup?
>>> 
>>> For cloud, there are a lot of options that could get you running with MUCH 
>>> more memory, which would save you lots of headaches getting KSM to work. My 
>>> favorite is EC2 spot instance on AWS.
>>> 
>>> On another note, I now setup most of my hosts with no swap, since 
>>> performance plummets whenever swap is used. YMMV.
>>> 
>>> 
>>> I am trying to get KSM working since each container is an identical replica 
>>> of the other (other than hostname/IP).  I have read a ton of information on 
>>> the ‘net about Ubuntu and KSM, yet I can’t seem to get any pages to share 
>>> on the host.  I am not sure if this is a KSM config issue or if LXD won’t 
>>> allow KSM between containers.
>>> 
>>> 
>>> 
>>> 
>>> 
>>> Here is what I have done thus far:
>>> ----------------------------------
>>> * Installed the ksmtuned utility and verified ksmd is running on each host.
>>> * Created the ksm_preload and ksm-wrapper tools per this site (the 
>>> https://github.com/unbrice/ksm_preload).
>>> * Created 50 identical Ubuntu 16.04 containers running nginx
>>> * Modified the nginx startup script on each container to include the 
>>> ksm_preload.so library; no issues running nginx.
>>> 
>>> (Note: since I could not find the ksm_preload library for Ubuntu, I had to 
>>> use the ksm-wrapper tool listed above)
>>> 
>>> All the relevant files under /sys/kernel/mm/ksm still show 0 (pages_shared, 
>>> pages_sharing, etc) regardless of what I do.
>>> 
>>> 
>>> Can any (@stgraber @brauner) confirm if KSM is supported with LXD?  If so, 
>>> what is the “magic” to make it work?  We really want to get 2-3x more sites 
>>> per container if possible.
>>> 
>>> 
>>> Have you read https://openvz.org/KSM_(kernel_same-page_merging) ? Some info 
>>> might be relevant. For example, it mentions something which you did not 
>>> wrote:
>>> 
>>> To start ksmd, issue
>>> [root@HN ~]# echo 1 > /sys/kernel/mm/ksm/run
>>> 
>>> Also the section about Tuning and Caveats.
>>> 
>>> -- 
>>> Fajar
>>> _______________________________________________
>>> lxc-users mailing list
>>> [email protected]
>>> http://lists.linuxcontainers.org/listinfo/lxc-users
>> 
>> _______________________________________________
>> lxc-users mailing list
>> [email protected]
>> http://lists.linuxcontainers.org/listinfo/lxc-users 
> 
> 
> -- 
> Tomasz Chmielewski
> _______________________________________________
> lxc-users mailing list
> [email protected]
> http://lists.linuxcontainers.org/listinfo/lxc-users

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