From: Roman Mamedov <rm@romanrm.ru>
To: "Fajar A. Nugraha" <list@fajar.net>
Cc: linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: fstrim on BTRFS
Date: Thu, 29 Dec 2011 10:37:36 +0600 [thread overview]
Message-ID: <20111229103736.26a3a07d@natsu> (raw)
In-Reply-To: <CAG1y0se+ctBx0YpsCGaW-8TKEN7PZix7PA8Eu-FzfVtkNPkkUQ@mail.gmail.com>
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On Thu, 29 Dec 2011 11:21:14 +0700
"Fajar A. Nugraha" <list@fajar.net> wrote:
> Slightly off-topic, how useful would trim be for btrfs when using
> newer SSD which have their own garbage collection and wear leveling
> (e.g. sandforce-based)?
>
> I'm trying fstrim and my disk is now pegged at write IOPS. Just
> wondering if maybe a "btrfs fi balance" would be more useful, since:
> - with trim, used space will remain used. Thus future writes will only
> utilized space marked as "free", making them wear faster
> - with "btrfs fi balance", btrfs will move the data around so (to some
> degree) the currently-unused space will be used, and currently-used
> space will be unused, which will improve wear leveling.
Modern controllers (like the SandForce you mentioned) do their own wear leveling 'under the hood', i.e. the same user-visible sectors DO NOT neccessarily map to the same locations on the flash at all times; and introducing 'manual' wear leveling by additional rewriting is not a good idea, it's just going to wear it out more.
--
With respect,
Roman
~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Stallman had a printer,
with code he could not see.
So he began to tinker,
and set the software free."
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next prev parent reply other threads:[~2011-12-29 4:37 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-28 16:57 fstrim on BTRFS Martin Steigerwald
2011-12-29 4:02 ` Li Zefan
2011-12-29 4:21 ` Fajar A. Nugraha
2011-12-29 4:32 ` Fajar A. Nugraha
2011-12-29 4:37 ` Roman Mamedov [this message]
2011-12-29 4:42 ` Fajar A. Nugraha
2011-12-29 5:29 ` cwillu
2011-12-29 10:52 ` Martin Steigerwald
2012-01-03 21:05 ` Chris Mason
2011-12-29 4:29 ` Fajar A. Nugraha
2011-12-29 9:39 ` Li Zefan
2011-12-29 9:52 ` Fajar A. Nugraha
2011-12-30 6:19 ` Li Zefan
2011-12-30 6:35 ` Fajar A. Nugraha
-- strict thread matches above, loose matches on Subject: below --
2014-10-31 0:21 Noah Massey
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