RE: Grid (RAC & Standalone) Unexpected Node Reboots Upon Device Path Failures

Other generic notes.

Normally you don’t set “Queue_if_no_path “ but set “no_path_retry N “  

The number can vary but a standard setting for say EMC Symmtrix with UCS is

    no_path_retry 6      

Matthew Parker

Chief Technologist

Dimensional DBA

425-891-7934 (cell)

D&B 047931344

CAGE 7J5S7 Dimensional.dba_at_comcast.net

<http://www.linkedin.com/pub/matthew-parker/6/51b/944/> View Matthew Parker's profile on LinkedIn

www.dimensionaldba.com <http://www.dimensionaldba.com/>  

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Dimensional DBA Sent: Monday, June 13, 2016 10:52 AM
To: fmhabash_at_gmail.com; 'Oracle-L Group' Subject: RE: Grid (RAC & Standalone) Unexpected Node Reboots Upon Device Path Failures  

Does it happen every time or sporadically?

Can you provide an example lun from your multipath.conf and what values you are using for those settings or combination of those settings since some are binary opposites of each other?

What UCS Manager version are you running and what firmware Bundle patch and on which blade type are you having problems with?

Is the error in the cluster logs and OS logs that all paths timed out?  

There are a variety of failure points and each failure point had a different solution.  

That includes an administrator modifying templates in UCS manager causing the nodes to reboot.    

Matthew Parker

Chief Technologist

Dimensional DBA

425-891-7934 (cell)

D&B 047931344

CAGE 7J5S7 Dimensional.dba_at_comcast.net

<http://www.linkedin.com/pub/matthew-parker/6/51b/944/> View Matthew Parker's profile on LinkedIn

www.dimensionaldba.com <http://www.dimensionaldba.com/>  

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of fmhabash_at_gmail.com Sent: Monday, June 13, 2016 10:05 AM
To: Oracle-L Group
Subject: Grid (RAC & Standalone) Unexpected Node Reboots Upon Device Path Failures  

We are experiences a perplexing issue that we have not been able to arrive at an RCA resolution. Grid nodes (can be RAC or standalone) boot unexpectedly & sporadically (not every time) when we failover a hardware component such as UCS fabric interconnect, an HBA, or a storage controller. On some systems, we also noticed filesystems going read-only.  

All devices are configured with multipathing of minim of 4 paths. Multipathing is offered via EMC PowerPath or Native Linux DM-MPIO.  

All nodes use 11gR2 ASM LVM, with subset using ASMLIB running on OEL 6.3-6.6 and RDBMS 11gR2  

I know there is a zillion factors to consider here, but to make things simple, let’s focus on dm-mpio for now. We believe, all these symptoms related to how the software (oracle ASM or Linux LVM) reacts to the loss of a path in a multipathed setup. So we focused on multipath.conf settings that control IO path failover. Namely …  

Path_retry

Queue_if_no_path

Polling_interval

Rr_min_io

Failback immediate  

1. Have you experienced issues like unexpected node reboots, filesystems going read-only when failing over at the hardware level I listed above?
2. What was you resolution.
3. How does your multipath.conf parameters listed above compare to yours?

Thanks all    

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