---
name: "qb-blackbox"
section: "8"
platform: "linux"
package: "libqb"
version: "2.0.10-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/qb-blackbox"
---

# qb-blackbox(8)

Display "flight data" from the "blackbox".

## NAME

qb-blackbox - Display "flight data" from the "blackbox".

## SYNOPSIS

**qb-blackbox** \[*blackbox-file*...\]

## DESCRIPTION

**qb-blackbox** prints out the logs (including debug logs) that were recorded using libqb's blackbox mechanism.

### Portability notes

Due to variations amongst platforms, some of which directly impact the libqb's blackbox format handling (e.g. page size), there's currently only the commitment that **qb-blackbox** shall decode the blackbox files recorded at the same platform (plus the same page size) while using libqb compiled with the same relevant compile-time options (e.g. **USE\_CACHE\_LINE\_ALIGNMENT**) as linked to this decoder. Otherwise, your mileage may vary.

## EXAMPLES

- Get info to help developers diagnose a crash.

  $ qb-blackbox /var/lib/corosync/fdata\
   Dumping the contents of /var/lib/corosync/fdata\
   Mar 23 20:58:57 message\_handler\_orf\_token():3677 install seq 0 aru 0 high seq received 0\
   Mar 23 20:58:57 message\_handler\_orf\_token():3696 retrans flag count 4 token aru 0 install seq 0 aru 0 0\
   Mar 23 20:58:57 old\_ring\_state\_reset():1487 Resetting old ring state\
   Mar 23 20:58:57 deliver\_messages\_from\_recovery\_to\_regular():1693 recovery to regular 1-0\
   Mar 23 20:58:57 memb\_state\_operational\_enter():1779 Delivering to app 1 to 0\
   Mar 23 20:58:57 sync\_abort():594 ENTERING sync\_abort()\
   Mar 23 20:58:57 sync\_save\_transitional():586 ENTERING sync\_save\_transitional()\
   Mar 23 20:58:57 member\_object\_joined():301 Member joined: r(0) ip(192.168.122.1) \
   Mar 23 20:58:57 sync\_abort():594 ENTERING sync\_abort()\

## SEE ALSO

[**qblog.h**(3)](/qblog.h/3.md)

## AUTHOR

Angus Salkeld