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From: Richard Weinberger <richard.weinberger@gmail.com>
To: JH <jupiter.hce@gmail.com>
Cc: linux-mtd@lists.infradead.org
Subject: Re: A big issue of NAND fragmentation
Date: Thu, 5 Sep 2019 13:54:28 +0200	[thread overview]
Message-ID: <CAFLxGvzqXs=m77Dmp+EVxYKM4gWc4AcU1ftW+S90rVtot1NvPg@mail.gmail.com> (raw)
In-Reply-To: <CAA=hcWTrrC1a_WSNb62ftn60fAMnq1jywVsjwess1=vGufXjLw@mail.gmail.com>

On Thu, Sep 5, 2019 at 3:27 AM JH <jupiter.hce@gmail.com> wrote:
>
> Hi,
>
> I am running kernel 5.1.0 on iMX6 using NAND flash, I write small data
> files about 250 bytes each every 5 minutes to a backup storage, the
> total size of all data files is about 600 KB, but du shown me 9.7M is
> used in that directory. I know NAND using page to flush files, how
> does the MTD handler NAND fragmentation?

If you force UBIFS (I assume you use it) to persist 250 bytes,
it has to waste a full NAND page. This is how NAND works.
But UBIFS can pack such data chunks upon garbage collect when
it runs out of space.

-- 
Thanks,
//richard

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  reply	other threads:[~2019-09-05 11:54 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-05  1:27 A big issue of NAND fragmentation JH
2019-09-05 11:54 ` Richard Weinberger [this message]
2019-09-06  6:03   ` JH
2019-09-06  7:02     ` Richard Weinberger
2019-09-06 11:18       ` JH

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