[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...
Regards.
--
Danti Gionatan
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