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From: Nikolay Borisov <nborisov@suse.com>
To: Hamish Moffatt <hamish-btrfs@moffatt.email>,
	Roman Mamedov <rm@romanrm.net>
Cc: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>,
	linux-btrfs@vger.kernel.org
Subject: Re: new database files not compressed
Date: Mon, 31 Aug 2020 15:57:40 +0300	[thread overview]
Message-ID: <41107373-cc61-ea3f-7ae9-c9eef0ee47f9@suse.com> (raw)
In-Reply-To: <c7415ce2-f025-6c31-60b7-f0b927ed4808@moffatt.email>



On 31.08.20 г. 15:54 ч., Hamish Moffatt wrote:
> On 31/8/20 9:15 pm, Roman Mamedov wrote:
>> On Mon, 31 Aug 2020 18:53:54 +1000
>> Hamish Moffatt <hamish-btrfs@moffatt.email> wrote:
>>
>>> $ sudo mount -O compress-force=zstd /dev/sdb /mnt/test
>> Specifying the filesystem mount options is done with -o, not -O.
>> See "man mount".
>>
> Argh, I messed up the dd test. It does work for dd from /dev/zeroes when
> mounted properly. It still doesn't compress my Firebird files though.
> 
> 
> $ mount | grep btrfs
> /dev/sdb on /mnt/test type btrfs
> (rw,relatime,compress-force=zstd:3,space_cache,subvolid=5,subvol=/)
> $ dd if=/dev/zero of=zeroes bs=32k count=1024
> 1024+0 records in
> 1024+0 records out
> 33554432 bytes (34 MB, 32 MiB) copied, 0.0244041 s, 1.4 GB/s
> $ sudo compsize zeroes
> Type       Perc     Disk Usage   Uncompressed Referenced
> TOTAL        3%      1.0M          32M          32M
> zstd         3%      1.0M          32M          32M
> $ zcat ~/*.zip | gbak -REP -page 16384 stdin test2.fdb
> $ sudo compsize test2.fdb
> Type       Perc     Disk Usage   Uncompressed Referenced
> TOTAL      100%      194M         194M         191M
> none       100%      194M         194M         191M
> $ isql-fb
> Use CONNECT or CREATE DATABASE to specify a database
> SQL> create database 'test3.fdb' page_size 16384;
> SQL> ^D
> $ sudo compsize test3.fdb
> Type       Perc     Disk Usage   Uncompressed Referenced
> TOTAL      100%      2.2M         2.2M         2.2M
> none       100%      2.2M         2.2M         2.2M
> 

This means the data being passed to btrfs is not compressible. I.e after
coompression the data is not smaller than the original, input data.

> 
> Hamish
> 

  reply	other threads:[~2020-08-31 12:57 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-30  9:35 new database files not compressed Hamish Moffatt
2020-08-31  2:20 ` Eric Wong
2020-08-31  2:44   ` Hamish Moffatt
2020-08-31  3:15   ` A L
2020-08-31  3:47 ` Zygo Blaxell
2020-08-31  8:53   ` Hamish Moffatt
2020-08-31  9:25     ` Nikolay Borisov
2020-08-31 10:40       ` Hamish Moffatt
2020-08-31 10:47         ` Nikolay Borisov
2020-08-31 12:56           ` Hamish Moffatt
2020-08-31 11:15     ` Roman Mamedov
2020-08-31 12:54       ` Hamish Moffatt
2020-08-31 12:57         ` Nikolay Borisov [this message]
2020-08-31 23:50           ` Hamish Moffatt
2020-09-01  5:15             ` Nikolay Borisov
2020-09-01  8:55               ` Hamish Moffatt
2020-09-02  0:32                 ` Hamish Moffatt
2020-09-02  5:57                   ` Nikolay Borisov
2020-09-02  6:05                     ` Hamish Moffatt
2020-09-02  6:10                       ` Nikolay Borisov
2020-09-02  9:57                     ` A L
2020-09-02 10:09                       ` Nikolay Borisov
2020-09-03 15:04                         ` A L
2020-09-02 16:16                       ` Zygo Blaxell
2020-09-03 12:53                         ` Hamish Moffatt
2020-09-03 19:44                           ` Zygo Blaxell
2020-09-04  8:07                             ` Hamish Moffatt
2020-09-05  4:07                               ` Zygo Blaxell
2020-09-03 15:03                         ` A L
2020-09-03 21:52                           ` Zygo Blaxell
2020-09-01  1:43 ` Chris Murphy

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