Re: makefs -t ffs makes too large image

From: Anthony Pankov <anthony.pankov_at_yahoo.com>
Date: Thu, 22 Aug 2024 15:24:05 UTC
Hello Miroslav,

You are  genius!

But the situation is a very frustrating. It is a default system and I did nothing  to turn the compression on.
So I was absolutely sure that compression is off. 

I'm sorry. 
Nevertheless having compression on by default is a very weird decision and is fully unexpected for me. I've never seen a big warning about default value of this vital parameter will be inverted.

On 12 -STABLE:

 # zfs get compression
NAME                       PROPERTY     VALUE     SOURCE
ps2                        compression  off       default

On 14-STABLE

 # zfs get compression
NAME                          PROPERTY     VALUE           SOURCE
tank                          compression  on              default
tank/bsdsrc                   compression  on              default

Thank you.

Thursday, August 22, 2024, 5:55:35 PM, you wrote:

> On 22/08/2024 12:52, Anthony Pankov wrote:
>> Hello,
>> > There is no much info about makefs so I ask here.
>> > I've tried to make UFS image via `makefs` of a directory sized 500Mb and get file of 1200Mb.
>> Is it a bug or feature? Is it related to source files that lies on  ZFS while making UFS image?
>> > #makefs -t ffs -B little -o label=rootfs -o version=2 -o softupdates=0 image/rootfs.ufs installed
>> > Calculated size of `image/rootfs.ufs': 1264320512 bytes, 14974 inodes
>> Extent size set to 32768
>> image/rootfs.ufs: 1205.8MB (2469376 sectors) block size 32768, fragment size 4096
>>          using 2 cylinder groups of 866.31MB, 27722 blks, 11136 inodes
>> > #du -hcd 1 installed/
>> > 512B    installed/media
>> 512B    installed/tmp
>> 512B    installed/mnt
>> 2,4M    installed/sbin
>> 259K    installed/var
>> 512B    installed/dev
>>   99K    installed/libexec
>> 835K    installed/bin
>> 384M    installed/usr
>> 9,7M    installed/rescue
>> 676K    installed/etc
>> 512B    installed/net
>> 5,0K    installed/root
>> 512B    installed/proc
>> 9,4M    installed/lib
>>   90M    installed/boot
>> 497M    installed/
>> 497M    total
>> > # tunefs -p image/rootfs.ufs
>> ...
>> tunefs: maximum blocks per file in a cylinder group: (-e)  8192
>> tunefs: average file size: (-f)                            16384
>> tunefs: average number of files in a directory: (-s)       64
>> tunefs: minimum percentage of free space: (-m)             8%
>> tunefs: space to hold for metadata blocks: (-k)            0
>> tunefs: optimization preference: (-o)                      time
>> tunefs: volume label: (-L)                                 rootfs

> Is it possible that you have enabled compression on source ZFS filesystem? Try to ad -A to you "du" command to see actual size of files, not compressed size on filesystem.

> Kind regards
> Miroslav Lachman




-- 
Best regards,
Anthony