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From: Gionatan Danti <g.danti@assyoma.it>
To: LVM general discussion and development <linux-lvm@redhat.com>
Cc: Ilia Zykov <mail@izyk.ru>
Subject: Re: [linux-lvm] Why doesn't the lvmcache support the discard (trim) command?
Date: Fri, 19 Oct 2018 22:54:26 +0200	[thread overview]
Message-ID: <17a367c7043400e4890738b00afcb011@assyoma.it> (raw)
In-Reply-To: <c6043f6f-f10a-5e6f-19ba-b50508e48ee0@redhat.com>

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
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it
email: g.danti@assyoma.it - info@assyoma.it
GPG public key ID: FF5F32A8

      parent reply	other threads:[~2018-10-19 20:54 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-18 22:56 [linux-lvm] Why doesn't the lvmcache support the discard (trim) command? Ilia Zykov
2018-10-19  9:12 ` Zdenek Kabelac
2018-10-19  9:42   ` Gionatan Danti
2018-10-19  9:49     ` Zdenek Kabelac
2018-10-19  9:55   ` Ilia Zykov
2018-10-19 10:58     ` Zdenek Kabelac
2018-10-19 12:45       ` Gionatan Danti
2018-10-19 13:08         ` Zdenek Kabelac
2018-10-19 13:16           ` Ilia Zykov
2018-10-19 17:00           ` Ilia Zykov
2018-10-22 10:54             ` Zdenek Kabelac
2018-10-19 20:54           ` Gionatan Danti [this message]

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