#SnapMirrorActiveSync resize issues...

1 messages · Page 1 of 1 (latest)

elfin fox
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Oh... do I regret suggesting SMAS to my customers? Oh yes! 😉
Apparently source and destination in the snapmirror sync relationship does not sync across the volume size of the source... so as you expand your source volume, your destination stays on the initial size...
And of cause you are unable to resize the destination... because it's a destiantion... so the "solution" from NetApp Support is to break the SM relationship... resize the destination and resync it again.. which would be fine with a normal SnapMirror, but with SMAS you have hosts attached which may use the destination volume as their preferred path... What a KB explains is that you need to unmount the LUN before breaking the SM... which is just a bit crazy to me... does anyone know if this is "fixed" in any future ONTAP to 9.16.1 ? Here is the KB: https://kb.netapp.com/on-prem%2Fontap%2FDP%2FSnapMirror%2FSnapMirror-KBs%2FError_Modifying_Autosize_Settings_for_SnapMirror_Active_Sync_Destination_Volume#

NetApp Knowledge Base
Error Modifying Autosize Settings for SnapMirror Active Sync Destin...
somber kettle
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do you use the AutomatedFailover policy or the AutomatedFailoverDuplex? Because for Duplex, there technically isn't really a "source" and a "destination" volume ...

elfin fox
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Yep it's AutomatedFailoverDuplex. But the destination volumes are read-only... And yes I am aware that this is technically "just" a XDP relationship, and not a SyncMirror as we know it... we have seen a difference in snapshots from source and destination... 🙂 There must be some underlying reason why they do it like this... I have a case open on this, and the "solution" is basically to break the mirrors, modify the destination and resync... something NetApp "forgot" to mention as they praise SMAS 😉 One of the reasons why we are currently considering just investing in four Cisco switches and converting it all to MCCIP

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...and BTW the configuration of the destination volumes wasn't even our choice, it was setup by OTV (version 10.2)... so the default autoresize is set up 98%.... even though the source is 80%... seems like a setting that should be editable on the destination, but no luck there..

true flint
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What's your ONTAP version?

true flint
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I edited the KB. Somehow the issue didn't get linked, but it's fixed.

elfin fox
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We are on 9.16.1P7 Do you mean that the fix is to be able to modify the autoresize value on the destination? 😉

true flint
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yes

elfin fox
# true flint yes

Please explain 🙂 Because the supporter on my case doesn't seem to think so...

true flint
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Can you provide me the case number?
I don't have much more of an explanation outside of CONTAP-480414 is tracking the inability to modify size and autosize parameters on a SMas destination, and is fixed in 9.16.1P8. But I can check with the case owner.

somber kettle
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vserver config override should always be possible. We had to use that a lot when the autosize mechanisms wouldn't work in SnapMirror/SVM DR relationships

elfin fox
elfin fox
true flint
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'vserver config override' is for SVMDR, I wouldn't expect it to work for SMas SAN.
In any case, I reached out to the case owner.

somber kettle