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Feature #11269

crush: quantify data movement for common straw -> straw2 migration scenarios

Added by Sage Weil over 4 years ago. Updated over 4 years ago.

Status:
Resolved
Priority:
Normal
Assignee:
Category:
-
Target version:
% Done:

0%

Source:
other
Tags:
Backport:
Reviewed:
Affected Versions:
Pull request ID:

Description

- confirm that with equal weights no data (or almost no data) moves
- quantify how much data shuffles when weights are different (e.g., [1,1,1,2], [1,2,3], etc.)

Mostly want a

strawtest.tgz (1.09 KB) Samuel Just, 05/06/2015 09:55 PM

History

#1 Updated by Sage Weil over 4 years ago

  • Description updated (diff)

#2 Updated by Sage Weil over 4 years ago

  • Target version changed from v0.95 to v9.0.2

#3 Updated by Samuel Just over 4 years ago

I see a significant amount of movement for 3 hosts each of which with 4 osds with weights 1 2 3 4. Attaching a tarball with the test maps and a script for doing the comparison. Update make_maps.sh to point at the right crushtool.

#4 Updated by Samuel Just over 4 years ago

  • Assignee set to Sage Weil

#5 Updated by Sage Weil over 4 years ago

Samuel Just wrote:

I see a significant amount of movement for 3 hosts each of which with 4 osds with weights 1 2 3 4. Attaching a tarball with the test maps and a script for doing the comparison. Update make_maps.sh to point at the right crushtool.

The mapping changes look about right to me. It'll depend on how much the weights within any given bucket vary. And good to see that mappings when weights are equal do not change at all.

#6 Updated by Samuel Just over 4 years ago

  • Status changed from New to Resolved

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