ONTAP Discussions

dedupe causes vol size to grow

sarbjit
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IHAC who are using FAS3020 running ONTAP 7.2.5.1.They enabled dedupe on a volume of 30GBwhich is not space reserved and the fractional reserve is set to 100%.The volume has a LUN of 25GB.

After enabling dedupe,customer saw the volume size increasing and it reached to a max autogrow limit of 60GB.Customer then disabled dedupe.(I believe they did using sis stop/sis off commands which saves the current fingerprint information) as the aggregate was also running out of space.

BEFORE dedupe                 AFTER dedupe

Vol->30GB                              vol-->60GB

lun->25GB                              lun->25GB

##  vol options ##

SCCM online     raid_dp, flex     nosnap=off, nosnapdir=off,
                           sis               minra=off, no_atime_update=off,
                                             nvfail=off,
                                             ignore_inconsistent=off,
                                             snapmirrored=off,
                                             create_ucode=on,
                                             convert_ucode=on,
                                             maxdirsize=20971,
                                             schedsnapname=ordinal,
                                             fs_size_fixed=off,
                                             guarantee=none, svo_enable=off,
                                             svo_checksum=off,
                                             svo_allow_rman=off,
                                             svo_reject_errors=off,
                                             no_i2p=off,
                                             fractional_reserve=100,
                                             extent=off,
                                             try_first=volume_grow,
                                             sis_logging=off,
                                             read_realloc=off
                Containing aggregate: 'aggr0'

   

#sis status -l shows the volume as :

Path:                    /vol/SCCM
State:                   Disabled
Status:                  Idle
Progress:                Idle for 30:11:29
Type:                    Regular
Schedule:                auto
Last Operation Begin:    Wed Jun 24 12:08:00 IST 2009
Last Operation End:      Wed Jun 24 12:23:00 IST 2009
Last Operation Size:     25 GB
Last Operation Error:    -
Stage:                   Done
Fingerprints Gathered:   6554516
Gathering Begin:         Wed Jun 24 12:08:00 IST 2009
Fingerprints Sorted:     6554516
Duplicate Blocks Found:  784739
Sorting Begin:           Wed Jun 24 12:17:39 IST 2009
Blocks De-duplicated:    784876
De-duping Begin:         Wed Jun 24 12:18:16 IST 2009
Fingerprints Deleted:    0
Checking Begin:          -

How can we reclaim the grown space in the volume?Is it because of the fingerprint information & checkpoints?can we delete the fingerprints and start a fresh dedupe using "sis start -s"

OR

Do a deletion of fingerprints and "sis undo" the volume first before starting it all over.

Any inputs will be highly appreciated.

best regards

sarbjit

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