Bug 1269793

Summary: [RFE] Add support for printing content of ring-buffer
Product: [Fedora] Fedora Reporter: Zdenek Kabelac <zkabelac>
Component: lvm2Assignee: LVM and device-mapper development team <lvm-team>
Status: CLOSED CURRENTRELEASE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: low    
Version: rawhideCC: agk, bmarzins, bmr, dwysocha, heinzm, jbrassow, jonathan, lvm-team, msnitzer, prajnoha, teigland, zkabelac
Target Milestone: ---Keywords: FutureFeature
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Enhancement
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2020-12-02 22:18:12 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Zdenek Kabelac 2015-10-08 08:53:26 UTC
Description of problem:

There is no 'easy' way to readout content of ring-buffer
e.g. when user is in dracut - there is no 'dd' command,
and retrieving content of previous metadata for being able to run 'vgcfgrestore' is getting tricky if the root volume with archive is unavailable.

So IMHO easiest would be to extent some lvm2 command to be able to dump content of present metadata in the ring-buffer into a file.

i.e.  --scanbufffer {all|#number}  to read last #number of entries and store them into a file - when a PV is given - list just metadata from this PV, otherwise scan and check all devices for metadata

Something in this direction would be quite useful.

It could be possible paired with 'vgcfgrestore --list' 
as i.e.  'vgcfgrestore --scandisk'

so it may eventually work directly without need of temporary file storage -
i.e. revert back by 'x' metadata from given time as listed....

Version-Release number of selected component (if applicable):
2.02.130

How reproducible:


Steps to Reproduce:
1.
2.
3.

Actual results:


Expected results:


Additional info:

Comment 1 David Teigland 2020-12-02 22:18:23 UTC
recent pvck --dump has similar capability