Bug 814764

Summary:	[RFE] Support 64-bit numbers of extents
Product:	[Community] LVM and device-mapper	Reporter:	Alasdair Kergon <agk>
Component:	lvm2	Assignee:	LVM and device-mapper development team <lvm-team>
lvm2 sub component:	Other	QA Contact:	cluster-qe <cluster-qe>
Status:	CLOSED WONTFIX	Docs Contact:
Severity:	medium
Priority:	medium	CC:	agk, dwysocha, heinzm, jbrassow, msnitzer, pasik, prajnoha, thornber, zkabelac
Version:	0-beta1	Keywords:	FutureFeature, Reopened
Target Milestone:	---	Flags:	rule-engine: lvm-technical-solution? rule-engine: lvm-test-coverage?
Target Release:	---
Hardware:	Unspecified
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Enhancement
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-10-28 15:50:04 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:

Description Alasdair Kergon 2012-04-20 15:25:55 UTC

Currently the number of extents in any LV is limited to 32 bits.  Large LVs use large extent sizes.

But with thin, mostly sparse, LVs, there comes a need for large LVs to have small extent sizes.

Consider compatibility, perhaps limiting this to thin LVs in the first instance.

Comment 1 Milan Broz 2012-04-23 06:10:14 UTC

*** Bug 815181 has been marked as a duplicate of this bug. ***

Comment 2 Tom Lavigne 2012-09-07 15:21:47 UTC

This request was evaluated by Red Hat Product Management for 
inclusion in the current release of Red Hat Enterprise Linux.
Since we are unable to provide this feature at this time,  
it has been proposed for the next release of 
Red Hat Enterprise Linux.

Comment 8 Heinz Mauelshagen 2016-07-27 17:26:03 UTC

We do map (small) thin chunks onto a thin pool DataLV with the current solution and keep track of their mapping on a thin MetaLV managed by the thin target, hence we don't require 64 bit extent numbers any more -> closing.

Feel free to reopen in case another requirement arises.

Comment 9 Zdenek Kabelac 2016-07-27 22:41:32 UTC

The reason why to support this is quite simple -

When you create 'small' extent size - you can't create large volume size -  so the comment 8 is not really relevant.

With 4MB extent you cannot create  4EB  thin volume - even though there is not other technical limitation -  the total size of LV is still expressed as 32bit * 32bit number.

Comment 10 Jonathan Earl Brassow 2019-10-28 15:50:04 UTC

I don't see us getting to this self-imposed feature.  I've also heard no requests for this from customers...