[linux-lvm] Why doesn't the lvmcache support the discard (trim) command?

Gionatan Danti g.danti at assyoma.it
Fri Oct 19 20:54:26 UTC 2018

Il 19-10-2018 15:08 Zdenek Kabelac ha scritto:
> Hi
> It's rather about different workload takes benefit from different
> caching approaches.
> If your system is heavy on writes -  dm-writecache is what you want,
> if you mostly reads - dm-cache will win.
> That's why there is  dmstats to also help identify hotspots and overal 
> logic.
> There is nothing to win always in all cases - so ATM 2 different
> targets are provided -  NVDIMMs already seems to change game a lot...
> dm-writecache could be seen as 'extension' of your page-cache to held
> longer list of dirty-pages...
> Zdenek

Thanks for these information. Reading a bit the commit which provide 
dm-writeback, it seems a sort of "L2 pagecache", right? It should be 
*very* interesting for use with NVDIMMs and/or fast NVME devices...


Danti Gionatan
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