Bug 1589347

Summary:	[RFE] gwcli: allow target-level control parameter overrides
Product:	[Red Hat Storage] Red Hat Ceph Storage	Reporter:	Jason Dillaman <jdillama>
Component:	iSCSI	Assignee:	Jason Dillaman <jdillama>
Status:	CLOSED ERRATA	QA Contact:	Manohar Murthy <mmurthy>
Severity:	high	Docs Contact:	Bara Ancincova <bancinco>
Priority:	high
Version:	3.2	CC:	anharris, ceph-eng-bugs, ceph-qe-bugs, hnallurv, jbrier, jdillama, mchristi, tchandra
Target Milestone:	rc	Keywords:	FutureFeature
Target Release:	3.2
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	ceph-iscsi-config-2.6-9.el7cp ceph-iscsi-cli-2.6-9.el7cp	Doc Type:	Enhancement
Doc Text:	.Target-level control parameters can be now overridden Only if instructed to by Red Hat Support, the following configuration settings can now be overridden by using the `gwcli reconfigure` subcommand: * cmdsn_depth * immediate_data * initial_r2t * max_outstanding_r2t * first_burst_length * max_burst_length * max_recv_data_segment_length * max_xmit_data_segment_length Tuning these variables might be useful for high IOPS/throughput environments. Only use these variables if instructed to by Red Hat Support	Story Points:	---
Clone Of:
Clones:	1625503 1650269 (view as bug list)		Environment:
Last Closed:	2019-01-03 19:01:22 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:	1625503, 1629656, 1650269

Description Jason Dillaman 2018-06-08 18:21:56 UTC

Description of problem:
Allow overriding of the following LIO configuration settings via the "[target]" section in "/etc/ceph/iscsi-gateway.cfg" and/or via a new "/iscsi-target/<IQN> reconfigure <key> <value>" action within the "gwcli".

	cmdsn_depth
	immediate_data
	initial_r2t
	max_outstanding_r2t
	first_burst_length
	max_burst_length
	max_recv_data_segment_length
	max_xmit_data_segment_length

Tweaking these settings are useful for high IOPS/throughput environments.

Comment 6 Yaniv Kaul 2018-07-18 13:18:18 UTC

Do we have performance numbers?
Is it for any release of lio (for example, applicable for next RHEL)?
Will it be helpful for any lio users with high iops, not just ceph?

Comment 7 Jason Dillaman 2018-07-18 14:02:54 UTC

I don't have any numbers recorded (since this wasn't a perf and scale exercise and I have limited access to resources). However, for an example, the default command depth is 64 IOs, so for fast storage w/ high queue-depth workloads, it would be nice to tweak 'cmdsn_depth' up.

This is just about exposing the knobs and levers that LIO already exposes via the Ceph 'gwcli' interface (multi-node-aware replacement for targetcli).

Comment 13 Mike Christie 2018-11-14 18:51:26 UTC

Is there a specific use case for supporting setting params in iscsi-gateway.cfg? If not, let's only allow setting params like this via tools like gwcli for now unless it is specifically documented in the RHCS guide.

gwcli allows us to only have to reset the iscsi sessions so it is less disruptive. It should only cause a a couple second delay in running IO. The rbd-target-gw service reload support should do something similar, but I think we still have some bugs when invalid values are used.

Comment 23 errata-xmlrpc 2019-01-03 19:01:22 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://access.redhat.com/errata/RHBA-2019:0020