[Deepsea-users] custom ratio proposals and filters

Jan Fajerski jfajerski at suse.com
Mon Apr 10 06:36:22 MDT 2017

Pulling this to the deepsea ml:

> > I'll send an email to the deepsea-users list once it is complete enough for
> > people to test it. So far filtering is only based on size. Options are data
> > and journal to pass different sizes for data and journal drive.They can
> > either contain a number (for exact selection) or a range.
> > What other attributes do you have in mind?
> I might want to select a particular vendor's SSDs to be data devices,
> combined with another vendors NVMe for the journal (or, in the future,
> WAL/metadata), and apply custom ratios to that while I'm at it.
The basic idea works like that. Drives are filtered and then the custom ratio is
applied. The decision to use size filters for now was mostly motivated by the
assumption, that this will provide enough filtering power on a per host basis.
I.e. I thought a host with two sets of SSDs that are the same size, but are
intended for a different use is sufficiently unlikely.
Though I think its no problem to add a vendor filter too.
> Or use that kind of SSDs directly, while those are meant as journals for
> my spinners. And maybe set some other BlueStore/XFS attributes
> differently too based on those.
> Or maybe my setup is simpler - everything that is rotational:1 is a data
> disk, and everything that isn't is a journal.
The idea is that all these setups can be achieved with the right size filters.
Currently build in is the assumption that rotational drive can only ever be data
device or standalone OSD, SSDs can be journal drives for spinners and NVMEs can

Jan Fajerski
Engineer Enterprise Storage
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton,
HRB 21284 (AG Nürnberg)

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