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Bug #18653

Improve compatibility between librbd + krbd for the data pool

Added by Jason Dillaman about 2 months ago. Updated about 2 months ago.

Status:
Pending Backport
Priority:
Normal
Target version:
-
Start date:
01/24/2017
Due date:
% Done:

0%

Source:
Tags:
Backport:
kraken
Regression:
No
Severity:
3 - minor
Reviewed:
Affected Versions:
ceph-qa-suite:
Release:
Needs Doc:
No

Description

The data pool feature results in a larger block name prefix. krbd uses fixed-sized data structures that will not currently hold this larger block name prefix. Need to (1) encode the pool id in hex to reduce bytes, (2) determine a new maximum block name prefix length, (3) ensure new images do not violate this new limit.


Related issues

Related to Bug #16887: ceph 10.2.2 rbd status on image format 2 returns "(2) No such file or directory" Resolved 08/01/2016
Copied to Backport #18771: kraken: Improve compatibility between librbd + krbd for the data pool New

History

#1 Updated by Ilya Dryomov about 2 months ago

It's just that krbd tries to avoid excessive memory allocations by packing things together. krbd can handle larger block name prefixes just fine as it has always been assumed to be an arbitrary string, so it's not really a compatibility issue -- just wanted to get some clarity on this given that generate_image_id() doesn't account for the metadata pool id in the data-pool case.

#2 Updated by Ilya Dryomov about 2 months ago

I'm not sure (1) is needed -- hex encoding won't save a lot and we are used to pool ids in decimal ;)
+1 on (2) and (3).

#3 Updated by Jason Dillaman about 2 months ago

Fair enough re: (1) if we don't need to squeeze every last byte out.

#4 Updated by Ilya Dryomov about 2 months ago

  • Related to Bug #16887: ceph 10.2.2 rbd status on image format 2 returns "(2) No such file or directory" added

#5 Updated by Jason Dillaman about 2 months ago

  • Status changed from In Progress to Need Review

#6 Updated by Jason Dillaman about 2 months ago

  • Status changed from Need Review to Pending Backport

#7 Updated by Nathan Cutler about 2 months ago

  • Copied to Backport #18771: kraken: Improve compatibility between librbd + krbd for the data pool added

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