fuel-dev team mailing list archive

[Roman Sokolkov <rsokolkov@xxxxxxxxxxxx>]

Andrew, Dmitry, thanks a lot! That is what i need.

Thanks


On Fri, Jan 17, 2014 at 10:08 PM, Dmitry Borodaenko <
dborodaenko@xxxxxxxxxxxx> wrote:

> Roman,
>
> The Facter snippet you linked to is only responsible for detecting the
> OSD Journal devices created during provisioning. Here is the logic in
> the disk provisioning script to actually create journal partitions:
>
>
> https://github.com/stackforge/fuel-library/blob/master/deployment/puppet/cobbler/templates/scripts/pmanager.py#L206
>
> As you can see, pmanager will limit the size of each journal partition
> to 10GB, so if your SSD is large enough to be greater than 10GB x
> (number of OSD HDDs), there will be enough unallocated space left on
> the SSD to create more journal partitions for new OSDs (make sure you
> pass --typecode option to sgdisk with the right GPT type GUID). And if
> you have more OSD drives than size of your SSD divided by 10GB, you're
> better off adding another SSD or even not using dedicated journal in
> the first place.
>
> -DmitryB
>
> On Fri, Jan 17, 2014 at 6:42 AM, Roman Sokolkov <rsokolkov@xxxxxxxxxxxx>
> wrote:
> > Andrey,
> >
> >> are we able to use multiple block devices for journal purpose right now?
> >
> > Answer on your question is yes. I've checked it already. I've used 2
> disks
> > for journal and 2 for OSD. Single journal disk mapped on single OSD disk
> in
> > this case. I assume if i will add additional (third) OSD disk, it will
> > remain without separate journal. Here is the logic.
> >
> > But the main question was:
> >
> > Is there ability to use one journal disk for multiple OSD disks?
> >
> > i.e. i have 4 SSDs and 20 HDDs in storage node. I want to use 1 SSD per 5
> > HDD. In this case SSD should contain 5 partitions.
> >
> > Thanks, Roman S.
> >
> >
> > On Fri, Jan 17, 2014 at 6:31 PM, Andrey Korolev <akorolev@xxxxxxxxxxxx>
> > wrote:
> >>
> >> Hello,
> >>
> >> Services team came with a question about Ceph setup - are we able to use
> >> multiple block devices for journal purpose right now?
> >>
> >> Also I am reviving back the issue with journal placement - our current
> >> approach to slice journal device to the equal chunk is not very good in
> >> terms of possible reconfiguration - e.g. you can not add more OSD
> daemons
> >> without shutting down every daemon on the selected nodes, doing journal
> >> flush and repartitioning. Can we please switch to the filesystem-based
> >> journal placement in the next release? Passing 'discard' option to the
> >> filesystem we will be able to maintain same level of wearout and with
> fixed
> >> or proportional journal size (e.g. to not allocate all free space) we
> will
> >> achieve greater maintenance flexibility.
> >
> >
> >
> >
> > --
> > Best regards, Roman Sokolkov
>
>
>
> --
> Dmitry Borodaenko
>



-- 
Best regards, Roman Sokolkov