Object Storage

Fc path drop from 4 paths to 3.

RuleS

Hi

 

I have a strange issue between a UCS and NetApp FAS2750 with OVM. I create a linux boot lun which the Linux Administrator creates a boot OVM on the UCS. The UCS and NetApp are direct connected in same rack (FlexPod). This customer of ours has 15 sites with these FlexPod's. The host boot lun, after a while will start seeing 3 paths instead of 4. This has happened at 2 other sites of theirs. ONTAP 9.9.1P3 is in operation at all sites. The igroup in question has several lun's attached but only the boot LUN's are affected. Therefore how can it be a NetApp problem. All SFP's wattage and cabling look good and in spec. I have taken the LUN offline and put back online, with same result. Rebooting host does not correct problem. I cannot modify or change igroup as multiple LUN's are on the same igroup.

To correct this problem I create a clone and map the clone and 4 paths are seen again. This has been the only way I have been able to correct the problem. This is not a solution as the host needs to be shut down to do this. 

Has anybody had same problem and got a solution please?

4 REPLIES 4

hmoubara

Hello @RuleS 

 

Do you have host utilities installed?

Also, do you have any portset created on the netapp side? if yes, are those portset bind to the igroup?

 

Check the below KB as well:

https://kb.netapp.com/Advice_and_Troubleshooting/Data_Storage_Systems/FlexPod_with_Infrastructure_Automation/Boot_LUNs_could_not_be_accessed_by_UCS

 

Thanks 

Hello hmoubara.

Host utilities are installed and no portsets set.

The KB mentioned does not pertain to this problem as the host boots from LUN and initially has 4 paths that the host can see. Intermittently one boot lun will drop one path which does not stop the host from working or booting. This host will continue to see 3 paths on boot lun until I clone volume, offline original lun and map this clone to the host for booting. All other LUN's on this igroup will always show 4 paths available. Only boot LUN's are intermittently affected.

Hello @RuleS 

 

Thanks for the reply. 

Are you seeing any errors on the storage end calling to this path being dropped? Also, you mention that creating a clone works fine; is the clone being split before connecting on the host side? Is the issue with this specific lun or are you able to create a new bootlun and still facing the same issue?

 

Thanks 

Hi hmoubra

I present the clone before splitting and then split after I know it is working.
The NetApp does not pick up the error at all as with 3 paths everything is still working and the igroup shows logged in.
The wattage on the SFP's for receive and transmit are all around the 500 uW.
All good as far as NetApp storage sees it.
I think I have mentioned that this happens at several sites on the Oracle Linux boot lun's only.
Other LUN's attached to igroup are always 4 paths.

Very very strange.
Never seen this before or heard of it before.


[Regards1]
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