On 31.08.20 г. 15:54 ч., Hamish Moffatt wrote:

On 31/8/20 9:15 pm, Roman Mamedov wrote:

quoted

On Mon, 31 Aug 2020 18:53:54 +1000
Hamish Moffatt [off-list ref] wrote:

quoted

$ 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