Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.

RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.

Description of problem:
Any chance of back porting the dm-service-time and dm-queue-length path selectors from dm-multipath that were included in 2.6.34 into the RHEL6 kernel for RHEL 6.4+?

These new algorythims pretty much bring dm-multipath into 100% capable of any alleged feature benefits over commercial products such as EMC PowerPath.

Having more than just simple round-robin is pretty much the only features missing from dm-multipath in comparison to those commercial products, so we are anxious to get these features in our RHEL systems native capabilites.

RHEL6 has always had these new path selectors.  Closing NOTABUG.

FYI, the path-selector that is used can be configured in /etc/multipath.conf

Either in the 'defaults' section (applies to all mpath devices), e.g.:

defaults
{
        ...
        selector                "queue-length 0"
}                                                                                                                                                                      

or in the per mpath 'device' section, e.g.:

devices
{
        device
        {
                ...
                path_selector   "service-time 0"
        }                                                                                                                                                              
}                                                                                                                                                                      

Not specifying a selector defaults to "round-robin 0"


Other RHEL6 multipath info is available here:
http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/DM_Multipath/MPIO_Overview.html
http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/DM_Multipath/config_file_devices.html

Thanks so much for the detailed answer.  It is much appreciated.