ASIS bug? Ontap 7.3.4

R_WOLTERSOM — Thu, 05 Jun 2025 06:02:27 GMT

Hi all,

A few days ago I was at a customer to configure some optimization settings on their FAS2020 running ONTAP 7.3.4 . The NetApp was configured without thin provisioning and deduplication.

After configuring some of the volumes with deduplication I noticed that two of the SAN volumes used for VMware where suddenly full for 100% after turning on dedup. I then tried to resize the volume with a few more GB but the space was swallowed immediately to 100%. Then I turned off dedup and resized the volume again with a few GB. And it still uses the allocated space immediately!

Here's some info about the configuration:

VOLUME options:

VMWAREOS01

nosnap=on, nosnapdir=on, minra=off, no_atime_update=off, nvfail=off,

ignore_inconsistent=off, snapmirrored=off, create_ucode=off,

convert_ucode=off, maxdirsize=9175, schedsnapname=ordinal,

fs_size_fixed=off, compression=off, guarantee=volume, 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,

read_realloc=off, snapshot_clone_dependency=off

LUN settings:

/vol/vmwareos01/vmwareos01/vmwareos01.lun 500.1g (536952700928) (r/w, online, mapped)

Comment: "VMWare"

Serial#: P3S6GoXjA-gI

Share: none

Space Reservation: enabled

Multiprotocol Type: vmware

Maps: VMWareESX=0

Reservation:

df -r -h vmwareos01

Filesystem total used avail reserved Mounted on

/vol/vmwareos01/ 600GB 600GB 0GB 392GB /vol/vmwareos01/

snap reserve 0GB 0GB 0GB 0GB /vol/vmwareos01/..

I then created a test volume with EXACT the same settings. This volume can be resized with no problems:

Options:

voltest

nosnap=on, nosnapdir=off, minra=off, no_atime_update=off, nvfail=off,

ignore_inconsistent=off, snapmirrored=off, create_ucode=on,

convert_ucode=on, maxdirsize=9175, schedsnapname=ordinal,

fs_size_fixed=off, compression=off, guarantee=volume, svo_enable=off,

svo_checksum=off, svo_allow_rman=off, svo_reject_errors=off, no_i2p=on,

fractional_reserve=100, extent=off, try_first=volume_grow,

read_realloc=off, snapshot_clone_dependency=off

luntest

/vol/TEST/TEST	500m (524288000)	(r/w, online)
	Comment: "test"
	Serial#: P3S6GorDQrOx
	Share: none
	Space Reservation: enabled
	Multiprotocol Type: vmware

reservations:

AST01> df -r -h TEST

Filesystem total used avail reserved Mounted on

/vol/TEST/ 2048MB 1002MB 1045MB 4KB /vol/TEST/

snap reserve 0GB 0GB 0GB 0GB /vol/TEST/

I browsed through NetApp online bugs, couldn't find any bugs that comes close to my situation.

Any help would be great!

Thanks in advance

-Rick

Re: ASIS bug? Ontap 7.3.4

haenggi — Fri, 17 May 2013 13:06:17 GMT

If you do not need snapshots, turn of fractional reserve of this volume.

vol options VMWAREOS01 fractional_reserve 0

This should help.

Cheers Michael

Re: ASIS bug? Ontap 7.3.4

R_WOLTERSOM — Fri, 17 May 2013 13:13:47 GMT

Thanks for the reply!

Still it doesn't really explain the reason why the test volume does work and the current volumes don't work..

Re: ASIS bug? Ontap 7.3.4

haenggi — Fri, 17 May 2013 13:17:45 GMT

The dedupe process creates a snapshot at the beginning, so I asume this filled the volume (due to the fractional_reserve). I asume as well, that you have an empty lun in the testvol, so if you create a snapshot there you don't need additional space for the fractional_reserve, as there is no data in the volume.

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ASIS bug? Ontap 7.3.4

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Re: ASIS bug? Ontap 7.3.4

Re: ASIS bug? Ontap 7.3.4