[lxc-users] writeback cache for all container processes?

[Tomasz Chmielewski]

On 2015-02-02 21:37, Fajar A. Nugraha wrote:

>> It's certainly possible to do "not applicable" kinds of things with
>> processes and their page cache, i.e.:
>> 
>> https://code.google.com/p/pagecache-mangagement/ [1]
>> 
>> Or here, disabling O_DIRECT and sync would be sort of matching
>> "feature-wise" with KVM's cache=writeback:
>> 
>> http://www.mcgill.org.za/stuff/software/nosync [2]
>> 
>> Is it possible to set things like this for all processes in a given
>> lxc container?
> 
> What are you trying to achieve?

I'm trying to achieve the equivalent of KVM's cache=writeback (or, 
"libeatmydata / nosync") for the whole container.


> If you want to disable sync for the container, the best you can do is
> probably use some filesystem that can do so. For example, zfs has
> "sync=disabled" per-dataset settings. So you can have "sync=standard"
> for filesystems used by the host, and "sync=disabled" for filesystems
> used by containers.

That's a weird advice, given that lxc are Linux containers, and ZFS is 
not in Linux kernel (I know that there are some 3rd party porting 
attempts, but it's not really applicable in many situations).

-- 
Tomasz Chmielewski
http://www.sslrack.com