Re: dar_manager - incremental backups and removed file

----------------------- Original message -----------------------
From: Denis Corbin <[email protected]>
To: [email protected]
Date: Sat, 20 Apr 2024 13:25:59 +0200
----------------------------------------------------------------

> Hi Joost,
>
> could you provide the output of 'dar -V'?

# dar -V

  dar version 2.7.13, Copyright (C) 2002-2023 Denis Corbin
  Long options support : YES

  Using libdar 6.7.1 built with compilation time options:
  gzip compression (libz) : YES
  bzip2 compression (libbzip2) : YES
  lzo compression (liblzo2) : NO
  xz compression (liblzma) : YES
  zstd compression (libzstd) : YES
  lz4 compression (liblz4) : NO
  Strong encryption (libgcrypt): YES
  Public key ciphers (gpgme) : YES
  Extended Attributes support : YES
  Large files support (>2GB) : YES
  ext2fs NODUMP flag support : YES
  Integer size used : 64 bits
  Thread safe support : YES
  Furtive read mode support : YES
  Linux ext2/3/4 FSA support : YES
  Mac OS X HFS+ FSA support : NO
  Linux statx() support : YES
  Detected system/CPU endian : little
  Posix fadvise support : YES
  Large dir. speed optimi. : YES
  Timestamp read accuracy : 1 nanosecond
  Timestamp write accuracy : 1 nanosecond
  Restores dates of symlinks : YES
  Multiple threads (libthreads): YES (1.4.0 - barrier using pthread_barrier_t)
  Delta compression (librsync) : NO
  Remote repository (libcurl) : NO
  argon2 hashing (libargon2) : YES

  compiled the Apr 10 2024 with GNUC version 13.2.1 20240210
  dar is part of the Disk ARchive suite (Release 2.7.13)
  dar comes with ABSOLUTELY NO WARRANTY; for details
  type `dar -W'. This is free software, and you are welcome
  to redistribute it under certain conditions; type `dar -L | more'
  for details.


> Have you recently recompiled or upgraded the dar binary used here to  
> make backups on that host?

It was recompiled recently (on the 10th), with me noticing the issue  
on the 13th or 14th.
But the other hosts are backed up using the exact same Dar-version.  
(Dar runs on the storage host which contains all the VMs. Some VMs are  
practically identical)

A backup is basically (in reality more complex due to automation) done  
as follows:
- filesystem snapshot is created
- snapshot is mounted
- snapshot is backed up using dar
- snapshot is umounted + removed

I actually wrote a backup system that automates all this using the  
storage layer commands (currently ZFS, I used LVM till about 6 years  
ago) and uses dar_manager statistics to determine if a potential  
"parent" for a backup is actually containing relevant files for a full  
restore. If not (both EA and Files are "0"), it is ignored and an  
older backup is selected as "parent"

Dar-files are encrypted and stored in the cloud. With monthly sets  
being written to tape. All this requires minimal monitoring by myself  
and generally runs fully automatic. If an error occurs, it's generally  
solvable by a simple restart, only rarely it requires further  
investigation. (Like this dar_manager issue).

--
Joost