Bug 1384230

Summary:	iSCSI performance is slow on secondary (non-optimised) paths during failover
Product:	[Red Hat Storage] Red Hat Ceph Storage	Reporter:	Paul Cuzner <pcuzner>
Component:	RBD	Assignee:	Mike Christie <mchristi>
Status:	CLOSED ERRATA	QA Contact:	Hemanth Kumar <hyelloji>
Severity:	high	Docs Contact:
Priority:	high
Version:	2.0	CC:	ceph-eng-bugs, hnallurv, kdreyer, pcuzner
Target Milestone:	rc
Target Release:	2.1
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:	ceph-iscsi-ansible-1.2-1.el7scon ceph-iscsi-config-1.2-1.el7cp	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-11-22 19:32:40 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:	1379890

Description Paul Cuzner 2016-10-12 21:28:43 UTC

Description of problem:
When a lun's primary path (active/optimised) is lost due to the owning gateway being down, client-side MPIO fails over correctly to the non-optimised paths. However, performance on the secondary paths is slow

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


How reproducible:
So far all tests with Windows 2012r2 have seen this behaviour.

Steps to Reproduce:
1.Create a ceph cluster with iscsi gateways
2.define rbd/luns to a client, ensuring the lun has AO and ANO paths
3.run an i/o job(e.g. iometer)
4.power off the gateway that owns the primary path, observice iops profile
5.bring the gateway back online - iops will return to prior level

Actual results:
During i/o over ANO paths, iops dropped significantly

Expected results:
i/o rates should be comparable to the AO path, when access is via secondary path(s)


Additional info:
The issue is with the alua configuration defined by the ceph-iscsi-config rpm.
A patch is available for this issue to test

Comment 3 Ken Dreyer (Red Hat) 2016-10-14 23:14:09 UTC

(In reply to Paul Cuzner from comment #0)
> A patch is available for this issue to test

Where is this patch?

Comment 4 Paul Cuzner 2016-10-14 23:31:47 UTC

this patch is included in the 1.2 release, now available to QE

Comment 6 Hemanth Kumar 2016-11-03 15:20:17 UTC

Compared the Performance on a Active-Optimised path vs Active-NonOptimised Path and I do not see any difference in I/O

Moving to verified state..

Comment 8 errata-xmlrpc 2016-11-22 19:32:40 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHSA-2016-2815.html