+Vivek

I don't know the exact bug here, but one possibility is that since you've
disabled the auto-extend, that it's leaving the metadata size at it's
default? There is indeed a relationship between the two and I did a lot of
testing around it to make sure we were not going to hit what you've hit :-/
 At that time however, we did not have the auto-extend feature.

So I think you may have found a situation where we need METADATA_SIZE=N but
you said you set that at 2%?
Can you paste the output of "docker info"  and "lsblk" please?

>From April 2015 when I last looked at this, the tests ran were to start
1000 httpd containers and measure the thinpool used size.  Here:


​

So, for 1000 rhel7+httpd containers, on-disk it was using about 3GB
(left-Y-axis).
And the metadata consumed was about 50MB (right-Y-axis).

You can see we concluded to set metadata @ 0.1% of the data partition size,
which in the case:
https://github.com/projectatomic/docker-storage-setup/blob/master/docker-storage-setup.sh#L220

I am wondering what your docker info will say.







On Fri, Jul 22, 2016 at 8:08 AM, Andrew Smith <[email protected]>
wrote:

> Hi
>
> We've been using docker-storage-setup (
> https://github.com/projectatomic/docker-storage-setup) to set up our
> CentOS LVM volumes.
>
> Because our block devices are fairly small and our containers don't write
> data inside them (and we hit issues with resizes being very slow) we have a
> static setup:
>
> AUTO_EXTEND_POOL=False
> DATA_SIZE=98%VG
>
> The intention is to just create the lv as big as we can up front, because
> we don't need that space for anything else. We leave 2% for metadata.
>
> However - we're running in to a problem, where our metadata volume is
> hitting 100% before out data volume gets close (sometimes, 60%). We're
> deploying kubernetes on these boxes, which garbage collects based on data
> usage not metadata usage, so we are often hitting the 100% and taking out
> boxes.
>
> What I'm struggling to understand is how much metadata a docker image or
> docker container uses. If I can find that out I can figure out a good
> data:metadata ratio. Is there a way for me to discover this?
>
> Or, as I suspect, am I missing something here?
>
> Thanks
> --
> Andy Smith
> http://andrewmichaelsmith.com | @bingleybeep
>
>


-- 

-- Jeremy Eder

Reply via email to