Possible to avoid doing a full backup on compressed header size error?

[Brock Palen]

I did a restore test on a host that has been using AI jobs for a while so a lot of long lived files have been coppied form media to media for a while, but in the restore I got a bunch of errors and the many retored files have 0 size.

On the host:
# ls -l P1020370.JPG
-rw-r--r-- 1 mlds-www mlds-www 2735024 Feb 1 2020 P1020370.JPG

Restore
# ls -l P1020370.JPG
---------- 1 root wheel 0 Feb 6 15:24 P1020370.JPG



06-Feb 15:46 myth-fd JobId 114962: Error: Compressed header size error. comp_len=61092, message_length=62214
06-Feb 15:46 myth-fd JobId 114962: Error: Compressed header size error. comp_len=61039, message_length=62161
06-Feb 15:46 myth-fd JobId 114962: Error: Compressed header size error. comp_len=64376, message_length=65498
06-Feb 15:46 myth-fd JobId 114962: Error: Compressed header size error. comp_len=64549, message_length=65671
06-Feb 15:46 myth-fd JobId 114962: Error: Compressed header size error. comp_len=61025, message_length=62147
06-Feb 15:46 myth-fd JobId 114962: Error: Compressed header size error. comp_len=60966, message_length=62088
06-Feb 15:46 myth-fd JobId 114962: Error: Compressed header size error. comp_len=63805, message_length=64927


Rather than just forcing a new full backup is there a way to check my volumes?
Or a way to do it as part of a job?

(and this is why you test your backups).


Brock Palen
bro...@mlds-networks.com
www.mlds-networks.com
Websites, Linux, Hosting, Joomla, Consulting

[Brock Palen]

Oh and not all files are at issue, I ran sha1sum on the soruce host and the restored data about half the files don’t match.

Brock Palen
bro...@mlds-networks.com
www.mlds-networks.com
Websites, Linux, Hosting, Joomla, Consulting

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[Bruno Friedmann (bruno-at-bareos)]

Hi Brock, could you check what sha1sum is recorded in the database especially for those file.

Seems that "da39a3ee5e6b4b0d3255bfef95601890afd80709" hash correspond to empty files.

[Brock Palen]

yeah I figured that out afterwards the files that were failingchceksum were all 0 size on the restore.
The mostly match up with the files with the Compressed header size error. But not always it’s even weirder so a specific example doing a restore one of the problem files:

The restored file has 0 size, but the joblog shows a restored size that’s non-zero even though it still showed error.

root@myth:/tmp/bareos-restores# stat mnt/xvdg/home/mpalen/public_html/var/resizes/Bolivia/bolivia/impedidos/07-22-08\ 064.jpg
File: mnt/xvdg/home/mpalen/public_html/var/resizes/Bolivia/bolivia/impedidos/07-22-08 064.jpg
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: 252,5 Inode: 26611710 Links: 1
Access: (0644/-rw-r--r--) Uid: (55637/ UNKNOWN) Gid: (55637/ UNKNOWN)
Access: 2023-07-02 02:09:03.000000000 -0400
Modify: 2020-02-01 17:57:47.000000000 -0500
Change: 2026-02-09 12:44:15.585422074 -0500
Birth: 2026-02-09 12:44:15.585422074 -0500



The job log has many lines like and then says it restored a size different than the origonal, but that restored size is non-zero.

2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=61266, message_length=14685
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=64376, message_length=65498
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=64468, message_length=65590
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=52209, message_length=53116
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=60520, message_length=61642
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=60938, message_length=62060
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=61158, message_length=62242
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=61213, message_length=62335
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=61154, message_length=62276
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=61202, message_length=62324
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=61305, message_length=62422
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=60837, message_length=61959
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=60723, message_length=61845
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=60710, message_length=61832
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=60754, message_length=61876
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=60667, message_length=61720
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=61309, message_length=62431
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=61191, message_length=62313
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=61352, message_length=62474
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=61139, message_length=62261
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=63626, message_length=64748
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=64058, message_length=44892
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=61104, message_length=62226
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=61072, message_length=62194
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=60934, message_length=62056
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=60488, message_length=61607
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=61079, message_length=62201
2026-02-09 12:44:14 myth-fd JobId 115093: Error: Compressed header size error. comp_len=60926, message_length=62048
2026-02-09 12:44:14 myth-fd JobId 115093: Error: findlib/attribs.cc:379 File size of restored file /tmp/bareos-restores/mnt/xvdg/home/mpalen/public_html/var/albums/Bolivia/bolivia/impedidos/07-22-08 060.jpg not correct. Original 125535, restored 65536.


One thing to note this is an older btrfs filesystem with compression turned on. All the other test restores (for which I have a large enough free space to test) restored fine.
With the exception of another fileset from this same AWS host but that filesystem is ext3. It was much smaller, I did a new full backup and tested restore and it was fine.

So I’m curious why this could happen, I could chalk it up to a fluke. I would like to have a way to test restores for larger restores for whcih I don’t have TBytes of idle disk around just in case.

Given this has been a long running always incremental system where there any bugged versions in the last few years? The client is gentoo, all my ohter tests were windows, or Ubuntu.

Brock Palen
bro...@mlds-networks.com
www.mlds-networks.com
Websites, Linux, Hosting, Joomla, Consulting

> To view this discussion visit https://groups.google.com/d/msgid/bareos-users/faf07f25-4490-4ef3-bca7-1ff8616cd125n%40googlegroups.com.

[Bruno Friedmann (bruno-at-bareos)]

Hi Brock,

We have some questions here:

- Do you know the first version of Bareos which was used to create the first backup ?

- What is the version used for restore ?

- Was compression in use in the fileset, did that one changes over the year (like changing from gzip to lz4 )

- Would it be possible to send us the resulting bsr of the restore ? 

- Not sure to decode correctly the workflow, could you just confirm the fact

  + Restore fails only on a specific host, with partition used for the restore being an old btrfs+compression

  + Restore can also failed on the same host with ext3 partition

  + Restore always succeed if done on any other target

In case only one host is failing, do you already do some memory checks (if any possible)?

As the client is gentoo (no official package) do you know how compilation was done ?

Regards.

[Brock Palen]

> On Feb 10, 2026, at 9:22 AM, Bruno Friedmann (bruno-at-bareos) <bruno.f...@bareos.com> wrote:
>
> Hi Brock,
>

> We have some questions here:
>
> - Do you know the first version of Bareos which was used to create the first backup ?

I don’t know but it’s probably at least 2 years old

>
> - What is the version used for restore ?

The machine running the director, sd, and the fd I’m restoring do are current. I even updated them and tried again with the same results.
The first problem was noticed with 25.0.2~pre13.add249aa9
Ran agian with: 25.0.2~pre101.a49ae5c10

>
> - Was compression in use in the fileset, did that one changes over the year (like changing from gzip to lz4 )

Compression has always been used (it’s an AWS to on prem backup so I want to minimize backup charges).
I did mess with compression settings a while back but I don’t htink for this client and it’s been gzip 6

I don’t have a way to confirm that, here is the fileset in question.

FileSet {
Name = "mlds_home"
Include {
Options {
compression=GZIP6
signature=MD5
}
File = "/mnt/xvdg/home"
}
Exclude { File = "/home/mysql" # maybe future mysql bin-log location

}
}



>
> - Would it be possible to send us the resulting bsr of the restore ?

Sure attached,
>