From: Ric Wheeler <ricwheeler@gmail.com>
To: Florian Weimer <fweimer@bfk.de>
Cc: Lukas Czerner <lczerner@redhat.com>,
Andreas Dilger <adilger@whamcloud.com>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-ext4@vger.kernel.org
Subject: Re: Feature request: e2fsck -z
Date: Wed, 10 Aug 2011 12:06:43 +0100 [thread overview]
Message-ID: <4E426643.3050709@gmail.com> (raw)
In-Reply-To: <82fwl9a5o5.fsf@mid.bfk.de>
On 08/10/2011 12:04 PM, Florian Weimer wrote:
> * Lukas Czerner:
>
>> On Wed, 10 Aug 2011, Florian Weimer wrote:
>>
>>> * Lukas Czerner:
>>>
>>>> You're right. It is a part of e2fsck and you can enable it with -E
>>>> discard.
>>> If the block device does not support TRIM, does this result in zeros
>>> being written instead?
>> Of course not, discard works only on devices which does support it. If
>> the device does not support discard it will to nothing.
> Oh, then it doesn't address hpa's use case (improving compression).
>
I think that there are multiple ways to help compression.
One would be to extract only the used data blocks (like file system specific
dump utilities can do), the other would be to zero with the discard or by
writing zeros to the unused blocks.
Ric
next prev parent reply other threads:[~2011-08-10 11:06 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-09 17:52 Feature request: e2fsck -z H. Peter Anvin
2011-08-10 6:34 ` Ric Wheeler
2011-08-10 8:16 ` Andreas Dilger
2011-08-10 8:22 ` Ric Wheeler
2011-08-10 9:35 ` Lukas Czerner
2011-08-10 10:55 ` Florian Weimer
2011-08-10 11:01 ` Lukas Czerner
2011-08-10 11:04 ` Florian Weimer
2011-08-10 11:06 ` Ric Wheeler [this message]
2011-08-10 11:09 ` Lukas Czerner
2011-08-10 13:25 ` Ted Ts'o
2011-08-10 14:34 ` Lukas Czerner
2011-08-10 7:54 ` Ron Yorston
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