Bug 623595 - move iscsi/iser to passthrough mode, fix functioning and failover time under DM multipath
Summary: move iscsi/iser to passthrough mode, fix functioning and failover time under ...
Alias: None
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: kernel
Version: 5.6
Hardware: All
OS: Linux
Target Milestone: rc
: ---
Assignee: Mike Christie
QA Contact: Storage QE
Depends On:
TreeView+ depends on / blocked
Reported: 2010-08-12 09:20 UTC by Or Gerlitz
Modified: 2011-02-25 10:54 UTC (History)
3 users (show)

Clone Of:
Last Closed: 2011-01-13 21:09:41 UTC

Attachments (Terms of Use)
patch which has the related fixes from upstream (60.79 KB, patch)
2010-08-12 09:20 UTC, Or Gerlitz
no flags Details | Diff

External Trackers
Tracker ID Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2011:0017 normal SHIPPED_LIVE Important: Red Hat Enterprise Linux 5.6 kernel security and bug fix update 2011-01-13 10:37:42 UTC

Description Or Gerlitz 2010-08-12 09:20:04 UTC
Created attachment 438383 [details]
patch which has the related fixes from upstream

Description of problem:

Remove some inefficiencies in the iser data path through
simplification and reducing the amount of code, using less atomic
operations, avoiding TX interrupts, moving to iscsi passthrough mode, etc.
As a result I was able to duplicate the amount of IOPS, upto about 300K
and to reduce the latency measured through iostat AWAIT report.
The upstream submission was done through a sequence of patches
and not as one big re-write, to ease with maintainance and tuning.

Fix bugs in the disconnection logic of iser which made the failover time with dm-multipathing to be too long, at least 120 seconds, wheres now it can get to be 30 seconds and below that. This part is the same as RHEL6 bugzilla 589174

Attached is the patch which addresses all that.

Comment 1 Or Gerlitz 2010-08-12 11:13:06 UTC
Forgot to mention that the patch was generated against / tested with kernel 2.6.18-211.el5

Comment 2 Mike Christie 2010-08-12 16:14:36 UTC
This seems fine to me.

It is upstream, Voltaire is doing testing, and they made the patch for us. Adding devel ack.

Thanks Or.

Comment 3 RHEL Product and Program Management 2010-08-12 16:19:17 UTC
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update

Comment 5 Jarod Wilson 2010-09-10 21:41:05 UTC
in kernel-2.6.18-219.el5
You can download this test kernel from http://people.redhat.com/jwilson/el5

Detailed testing feedback is always welcomed.

Comment 8 errata-xmlrpc 2011-01-13 21:09:41 UTC
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.


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