ONTAP Discussions

7-mode deduplication 100%

Hi All


i am working with a FAS2050 with 2.4TB on each controller


yesterday we started to enable dedup 1 volume at a time (excluding vol0)


vol2 went from 412GB @ 96% to 63% (400GB lun)


whihc was a great start


today vol3 went from 415GB 94% to 100% (251GB lun) instantly and says snapshot creation failed


what would be the reason for this? there are no snapshot copies visable from oncommand


any ideas


Re: 7-mode deduplication 100%

De duplication creates snapshot internally. So it may happen. The first thing to check would be fractional reserve settings.

Re: 7-mode deduplication 100%

can yo give me some guidance on the commands?

Re: 7-mode deduplication 100%

i see there is an enable fractional reserver 100%


i am investigating that now i can just disable this yes?

Re: 7-mode deduplication 100%

Fractional reserve ensures your LUNs won't suddenly get out of space. Make sure you understand implications before disabling it.

Re: 7-mode deduplication 100%

okay thank you - i have taken off the fractional reserver whilst i run the dedup as there is plenty of space and no backups are performed using storage snapshots


when the dedup has completed i will re-enable



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