[ovirt-users] best way to remove SAN lun

[Nir Soffer]

On Tue, Feb 21, 2017 at 6:12 PM, Adam Litke <alitke at redhat.com> wrote:
>
>
> On Tue, Feb 21, 2017 at 10:19 AM, Gianluca Cecchi
> <gianluca.cecchi at gmail.com> wrote:
>>
>> Hello,
>> currently I have a cluster of 3 hosts where each one has FC SAN
>> connectivity to 4 LUNs: 3 are already configured as storage domains (1TB,
>> 2TB, 4TB), one is free, not allocated.
>> See here for screenshot:
>>
>> https://drive.google.com/file/d/0BwoPbcrMv8mvRVZZMTlNcTQ5MGs/view?usp=sharing
>>
>> At the moment the command "multipath -l" run on hosts shows all the 4
>> LUNs.
>>
>> Now I want to do 2 things at storage array level:
>>
>> - remove the 2TB storage domain LUN
>> - remove the 20Gb LUN not yet allocated
>>
>> What is the correct workflow, supposing I have already emptied the 2TB
>> from VM disks ad such?
>> Select 2Tb SD, then Datacenter subtab, then "maintenance", detach" and at
>> the end "remove"?
>
>
> Yes, these should be your first steps.
>
>>
>> I think I continue to see 4 LUNs at this point, correct?

We do not manage devices, so this must be performed manually by
the system administrator.

To remove devices, you have to:

1. On the storage server, unzone the devices so the host(s) will not see them
    This must be done before you remove the multipath device and
paths, otherwise
    vdsm will discover the device again during the periodic scsi/fc rescans.

2. On all hosts ,remove the multipath device and the underlying scsi devices,
    as explained here:
    https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Storage_Administration_Guide/removing-path-to-storage-device.html

Nir

>
>
> Yes.
>
>>
>> Now I proceed with removal of lun at storage array level?
>>
>> Should I select an SD line and then "Scan disks" to see refresh the SAN
>> and see in multipath only 2 of them at the end?
>> Or any manual command at host level before removal from array?
>
>
> After removing the storage domains you should be able to remove the luns.  I
> am not extremely familiar with the multipath and low-level scsi commands but
> I would try the scan disks button and if the luns are not gone from your
> host you can manually remove them.  I think that involves removing the
> device from multipath (multipath -d) and deleting it from the scsi
> subsystem.
>
>> Thanks in advance
>
>
> Hope this helped you.
>
>
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