Hi,

    I done just now small test:
1. create squashfs backup with Documents (3.5GiB -> 2.4GiB)
2. overwrite by random data (/dev/urandom) 1MiB inside squashfs image
3. compare all files from source directory and mounded image (fuse)
Result?
1. One file are not accessible (I/O error during read). All rest ware 
OK.

squashfs have random (block) access. It's not like tar.gz and others
tars with linear compression. TAR was create for archive on tapes
without random (block) access. Squashfs is dedicated for e.g. ISO live
or embedded ROMs. It's easier to recovery data from squashfs image then
even raw TAR archive. And it's easy to burn it on optical disk.

And one more thing. RO image have one huge advantage over set of files -
you can create one file with hashes and verify image in one shot.

---
Best regards (Pozdrawiam),
Jakub Juszczakiewicz
Krypto-IT

W dniu 2024-05-30 13:49, Antony Stone napisał(a):
> On Sunday 26 May 2024 at 17:57:06, Jakub Juszczakiewicz via Dng wrote:
>
>> Hi all,
>>

>>     For full backup nice tool is mksquashfs.

>
> I never feel comfortable about a backup which is in a compressed
> format.
>
> If you simply copy every file of your valuable data to a standard file
> system
> somewhere else, and then that file system gets somehow corrupted, you
> stand a
> good chance of losing only a very few of your files.
>
> If you copy your data to something using a cmpression algorithm and the
> resultant file then gets somehow corrupted, you stand a good chance of
> being
> able to recover nothing at all.
>
> Given the modern costs of disk capacity, and the fact that if you need
> to
> recover something from backup you want the process to be quick, simple
> and
> reliable, I would choose a process which uses more disk space over
> something
> which conserves disk space but endangers restore speed, simplicity or
> reliability.
>
>
> Antony.
>
> --
> This email was created using 100% recycled electrons.
>

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