From: Li Zefan <lizf@cn.fujitsu.com>
To: uzytkownik2@gmail.com
Cc: linux-btrfs@vger.kernel.org
Subject: Re: Inefficient storing of ISO images with compress=lzo
Date: Mon, 19 Sep 2011 11:13:19 +0800 [thread overview]
Message-ID: <4E76B34F.9030206@cn.fujitsu.com> (raw)
In-Reply-To: <4E76AEB9.4080109@cn.fujitsu.com>
Li Zefan wrote:
> Maciej Marcin Piechotka wrote:
>> I've noticed that:
>>
>> - with x86-64 Fedora 15 DVD install images:
>> - du -sh <ROOT VOLUME> was 36 GB
>> - btrfs df | grep -i data have shown over 40 GB used
>> - without
>> - du -sh <ROOT VOLUME> is 34 GB
>> - btrfs df | grep -i data have shown less then 34 GB used
>>
>> It seems that iso files are considered compressable while they may not be (and penalty is severe - 3x).
>>
>
> With compress option specified, btrfs will try to compress the file, at most
> 128K at one time, and if the compressed result is not smaller, the file will
> be marked as uncompressable.
>
> I just tried with Fedora-14-i386-DVD.iso, and the first 896K is compressed,
> with a compress ratio about 71.7%, and the remaining data is not compressed.
>
correct: the compression ratio is 38.3%, pretty good :)
next prev parent reply other threads:[~2011-09-19 3:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-18 23:32 Inefficient storing of ISO images with compress=lzo Maciej Marcin Piechotka
2011-09-19 2:53 ` Li Zefan
2011-09-19 3:13 ` Li Zefan [this message]
2011-09-19 23:06 ` Maciej Marcin Piechotka
2011-09-20 2:19 ` Li Zefan
2011-09-20 14:29 ` David Sterba
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4E76B34F.9030206@cn.fujitsu.com \
--to=lizf@cn.fujitsu.com \
--cc=linux-btrfs@vger.kernel.org \
--cc=uzytkownik2@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).