Oracle Linux 6.5 multipath misconfiguration
2015-01-28 06:05 AM
We inherited a Oracle Linux 6.5 server with a multipathing problem. It's connected to a FAS3170 HA pair, 8.1.3P1 7-mode, with 2xQLE2560 HBAs. ALUA is enabled on the igroups, SAN zoning looks correct, but all I/O traverses one HBA and one target port on the NetApp. This is causing a lot of traffic to traverse the vtic and "FCP partner path mismatch" errors.
On the server, we see multipathd errors getting device and ioctl errors "adding target to table." multipath -ll output looks like this:
mpathv (WWID...) dm-29 NETAPP,LUN
size=500G features=`1 queue_if_no_path` hwhandler=`1 alua` wp=rw
|-+- policy='round-robin 0' prio=50 status=active
| |- 7:0:1:13 sdau 66:224 active ready running
| `- 8:0:0:13 sdca 68:224 active ready running
`-+- policy='round-robin 0' prio=10 status=enabled
| 7:0:0:13 sdo 8:224 active ready running
`- 8:0:1:13 sddg 70:224 active ready running
NetApp Linux Host Utility Kit version 6.2 is installed. The sanlun lun show -pv all output for one lun:
ONTAP Path: netapp3:/vol/DataA/data1.lun
LUN size: 500.1g
Controller CF State: Cluster Enabled
Controller Partner: netapp4
Multipath Provider: Unknown
state path type /dev/ node host adapter controller target port
up secondary sddg host8 0c
up primary sdca host8 0d
up primary sdau host7 0c
up secondary sdo host7 0d
On this disk, iostat shows all I/O going to /dev/sdo, from adapter host7 to target netapp4:0d across the vtic to netapp3.
I think there's something wrong in the multipath.conf:
getuid_callout "/lib/udev/scsi_id -g -u -d /dev/%n"
path_selector "round-robin 0"
hardware_handler "1 alua"
I notice that user_friendly_names is set to "yes" where best practice is "no." I want to change this, but I don't know if this is the problem.
Are the multipath.conf defaults and device section necessary anymore in after 6.4? The HUK 6.2 Installation and Setup Guide and Recommended Host Settings aren't clear. The Install Guide makes it seem the blacklist is all that's needed. The SnapDrive 5.2.2 documentation is clear on pages 131-132 : You do not have to set any values in the /etc/multipath.conf file if you are using either Red Hat Enterprise Linux (RHEL) 6.4 or later or Oracle Linux 6.4 or later. However, SnapDrive for UNIX configuration you must still maintain a dummy /etc/multipath.conf file, which can either be empty or contain the blacklisting info, if required.
Do these errors look like a multipath.conf problem?
Thank you for reading and any advice would be appreciated.
Knowledge Base Articles used: