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From: JH <jupiter.hce@gmail.com>
To: Richard Weinberger <richard.weinberger@gmail.com>
Cc: linux-mtd@lists.infradead.org
Subject: Re: A big issue of NAND fragmentation
Date: Fri, 6 Sep 2019 16:03:55 +1000	[thread overview]
Message-ID: <CAA=hcWT0=ny6hxDgxZVTU6jbAYS80nizw3+PVVWzgW6poXuMwQ@mail.gmail.com> (raw)
In-Reply-To: <CAFLxGvzqXs=m77Dmp+EVxYKM4gWc4AcU1ftW+S90rVtot1NvPg@mail.gmail.com>

Hi Richard,

On 9/5/19, Richard Weinberger <richard.weinberger@gmail.com> wrote:
> 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.

Yes, I use UBIFS, was your word "force" means "write" or did you
allude there would be an alternative to avoid forcing UBIFS persist
250 bytes?

Waiting for out of space would be too risk, alternatively, I should
have a UBIFS partition for the data storage, if it runs out of space,
it won't impact the root file system.

Thank you Richard.

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  reply	other threads:[~2019-09-06  6:04 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
2019-09-06  6:03   ` JH [this message]
2019-09-06  7:02     ` Richard Weinberger
2019-09-06 11:18       ` JH

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