topic Re: missing disk space? in ONTAP Discussions

missing disk space?

calvincnetapp — Thu, 05 Jun 2025 06:55:15 GMT

Very new to NetApp filers and having issues with disappearing disk space.

We have a FAS2020 and ds14mk2 filer.

In all we have 26x 500GB disks.

We have 2 aggregates, one with 3 disks (aggr0), the other with 14 disks (aggr1). Each aggregate has only one raid group.

In the aggr1, we have 3 volumes holding an assortment of LUNs and CIFS shares.

Ok so we seem to be missing storage space at each level of the storage unit.

Aggregate level (Aggr1)

The filer reports 4.14TB as total space for 14 disks with raid-dp

when it should be (14-2)*500GB = 6TB ?

Volume Level (aggr1)

We have 3 volumes on the aggr1 with sizes {500GB, 2TB and 1.2TB} = 2.7TB

The aggregate size is 4.14TB, free space should be 4.14-2.7 = 1.44TB but it's only showing 25GB??

Obviously i'm missing something.. help.

Re: missing disk space?

scottgelb — Mon, 09 May 2011 19:29:52 GMT

A 500GB drive right sizes to 413.194GB and after WAFL it right sizes to 371.877GB.

For your 14 drive aggregate... 12 data drives * 371.877 = 4.36TB. But then subtract .05% aggregate accounting... 4.36 * .995 = 4.34TB ... then the default aggregate reserve is 5% so 4.34TB * .95 = 4.12TB.... close to your 4.14 to see where the space goes. You can lower the aggregate snap reserve "snap reserve -A" but won't get more than 4.34TB usable by doing that.

For the free space issue, something isn't right below... please post "df -Ah", "df -h" and "aggr show_space -h", "aggr status" and "vol status" output... from those 5 commands we should be able to see where the space is...

Re: missing disk space?

calvincnetapp — Tue, 10 May 2011 13:40:08 GMT

Hey Scott

thanks so much for your reply!! ok tso that's sorted out the drive sizing then.

here's the dump from the commands:

df -Ah
Aggregate                total       used      avail capacity
aggr0                    353GB      335GB       17GB      95%
aggr0/.snapshot           18GB     1305MB       17GB       7%
aggr1                   4239GB     4213GB       25GB      99%
aggr1/.snapshot          223GB      133GB       89GB      60%

df -h
Filesystem               total       used      avail capacity Mounted on
/vol/vol0/               268GB      339MB      267GB       0% /vol/vol0/
/vol/vol0/.snapshot       67GB       13MB       67GB       0% /vol/vol0/.snapshot
/vol/vol1/              2048GB     1828GB      219GB      89% /vol/vol1/
/vol/vol1/.snapshot        0GB        0GB        0GB     ---% /vol/vol1/.snapshot
/vol/CIFSVOL/            500GB      244GB      255GB      49% /vol/CIFSVOL/
/vol/CIFSVOL/.snapshot      125GB        0GB      125GB       0% /vol/CIFSVOL/.snapshot
/vol/vol2/              1228GB      902GB      326GB      73% /vol/vol2/
/vol/vol2/.snapshot      307GB        0GB      307GB       0% /vol/vol2/.snapshot

aggr show_space -h
Aggregate 'aggr0'

Total space WAFL reserve Snap reserve Usable space BSR NVLOG
413GB 41GB 18GB 353GB 0KB

Space allocated to volumes in the aggregate

Volume Allocated Used Guarantee
vol0 338GB 3735MB volume

Aggregate                       Allocated            Used           Avail
Total space                         338GB          3735MB            17GB
Snap reserve                         18GB          1305MB            17GB
WAFL reserve                         41GB            20MB            41GB

Aggregate 'aggr1'

Total space WAFL reserve Snap reserve Usable space BSR NVLOG
4958GB 495GB 223GB 4239GB 0KB

Space allocated to volumes in the aggregate

Volume                          Allocated            Used       Guarantee
vol1                               2072GB          1623GB          volume
CIFSVOL                             630GB           250GB          volume
vol2                               1554GB           775GB          volume

Aggregate                       Allocated            Used           Avail
Total space                        4258GB          2649GB            25GB
Snap reserve                        223GB           133GB            89GB
WAFL reserve                        495GB           314MB           495GB

vol status
         Volume State      Status            Options
           vol0 online     raid_dp, flex     root, nosnap=on
           vol1 online     raid_dp, flex
           vol2 online     raid_dp, flex
        CIFSVOL online     raid_dp, flex

Re: missing disk space?

scottgelb — Tue, 10 May 2011 16:28:07 GMT

The space usable you are looking for is in volume snapshot space. CIFSVOL and vol2 are 500gb and 1228gb in user space but also have 125gb and 307gb reserved for snapshots. It looks like no snapshot schedule is in place since used is 0gb for these volumes. With snapshot space you are using 4208gb close to the 4213 reported.. -h output difference..

Most run snapshots and we always recommend snapshots. If you're not going to use snaposhots (let us know why first.. Would be a separate debate on here ) then you can remove snap reserve with "snap reserve volname 0"... But not something we recommend unless just a scratch pool or no snaps needed..

Typos Sent on Blackberry Wireless

Re: missing disk space?

calvincnetapp — Wed, 11 May 2011 16:46:51 GMT

Scott wow thanks for all your help! this has been REALLY educational