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Bug 1505383

Summary:	sometimes JBOD mode yields bad performance
Product:	[Red Hat Storage] Red Hat Ceph Storage	Reporter:	Ben England <bengland>
Component:	Documentation	Assignee:	Aron Gunn <agunn>
Status:	CLOSED CURRENTRELEASE	QA Contact:	ceph-qe-bugs <ceph-qe-bugs>
Severity:	high	Docs Contact:	John Brier <jbrier>
Priority:	high
Version:	3.0	CC:	agunn, asriram, ddharwar, kbader, kdreyer, pdonnell, tchandra, ymane
Target Milestone:	z1
Target Release:	3.2
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-07-09 08:32:57 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:
Bug Depends On:
Bug Blocks:	1668330

Comment 4 Patrick Donnelly 2018-02-22 18:53:55 UTC

*** Bug 1547775 has been marked as a duplicate of this bug. ***

Comment 6 Ben England 2019-01-24 13:38:33 UTC

Patrick, I'm not recommending RAID striping.  I'm just pointing out that on MegaRAID-style controllers, if you want writeback caching you need to explicitly expose each HDD as a "virtual drive" or LUN, and the syntax for doing that is to define a RAID0 with a single drive.  This allows you to tell the controller to use writeback caching on the drive.  Sorry if this wasn't clear in original post.