ONTAP preventing ctime update when using Robocopy | NetApp | Page 1

grizzled sundial Apr 10, 2025, 10:43 PM

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I've run into this issue twice now with different customers where ACL's get repeatedly copied by robocopy because ONTAP doesn't allow ctime to be updated to a time in the past by CIFS clients. The following KB has an internal note about how to change this behaviour with a bootarg which i have tested successfully. https://kb.netapp.com/on-prem/ontap/da/NAS/NAS-KBs/Why_is_Ctime_not_updated_when_copying_a_file_from_a_Windows_client_to_a_CIFS_share however the customer I'm working with at the moment is mainly NFS workload and I am not sure what changing this behaviour will do to NFS clients? Are we going to cause any problems for NFS clients by allowing ctime to be set to a time in the past with this bootarg?

NetApp Knowledge Base

Why is Ctime not updated when copying a file from a Windows client ...

lyric steppe Apr 10, 2025, 11:53 PM

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not really sure how that would work with NFS
But I would suggest/recommend using XCP instead of robocopy if possible

radiant bobcat Apr 11, 2025, 6:15 AM

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XCP over CIFS has the same limitation with regards to ctime though

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we have set the bootflag for a few customers in the past, and we never encountered any issues with NFS clients, so I'd say you should be safe

radiant bobcat Apr 11, 2025, 6:48 AM

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at most, it would allow NFS clients to do the same (i.e. set ctime before the actual creation time)

lyric steppe Apr 11, 2025, 6:50 AM

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still having set the bootflag, was just referring to using xcp instead of robocopy for the transfer

radiant bobcat Apr 11, 2025, 7:45 AM

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ah okay, sorry, misunderstood that

grizzled sundial Apr 11, 2025, 10:06 PM

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Thanks for the replies

#ONTAP preventing ctime update when using Robocopy