fc06-053 thin provisioning for iscsi and fc

FC06-053Thin Provisioning for iSCSI and FC

Rick Jooss

SANiSAN Business Unit

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Agenda

What is Flexible or Thin Provisioning

Types of Thin Provisioning

ONTAP Variables

Configurations– Default Configuration– Snapshot - Snapshot Auto delete– Snapshot - Volume Auto grow– Snapshot - Volume guarantee none– LUN - Volume guarantee none– LUN - LUN reservation disabled

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What is Thin Provisioning?

Presenting more space to the servers than the storage systems actually contains

Classic examples from other industries– Banks – Water Companies– Electric Companies– Insurance Companies

Large systems are needed

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Snapshot Space– Creating, mapping and snapshotting 100 x 100GB

LUNs with less than 20+ TB (< 2X + Δ)– In the NAS world snapshot space is always thin

provisioned

LUN Space– Creating and mapping 10TB (100 x 100GB) LUNs

when the storage system only has 8TB– Only makes sense when one is not creating

snapshots because having less than 10TB with snapshots is not reasonable

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Agenda



ONTAP Variables


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ONTAP variables affecting space usage

ONTAP Variables – Guarantee– LUN reservation – Fractional (space) Reservation– Snap Reserve– Auto Delete– Auto grow– Try first

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Guarantees

Set on a per volume basis Determines when space is allocated from the aggregate Possible settings

– Volume (default) • Space is reserved from the aggregate at volume creation time• This space is not available to other volumes regardless of how

much is really used– None

• No space is reserved from the aggregate at volume creation time• Space is taken from the aggregate as data is written• Allows thin provisioning of volumes• Any individual volume still is not allowed to take more space

than its size– File

• The same as none but allows individual LUNs (or files) to set space reservations to ensure they have adequate space

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LUN Reservation

Set on per LUN basis

Determines when space is allocated from the volume

Possible settings– enabled (default)

• Space is reserved from the volume at LUN creation time• This space is not available to other LUNs or files

regardless of how much is really used– Disabled

• No space is reserved from the volume at volume LUN time• Space is taken from the volume as data is written

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Guarantees

Set on a per volume basis Determines when space is allocated from the aggregate Possible settings

– Volume (default) • Space is reserved from the aggregate at volume creation time• This space is not available to other volumes regardless of how

much is really used– None

• No space is reserved from the aggregate at volume creation time• Space is taken from the aggregate as data is written• Allows thin provisioning of volumes• Any individual volume still is not allowed to take more space

than its size– File

• The same as none but allows individual LUNs (or files) to set space reservations to ensure they have adequate space

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LUN Reservation

Set on per LUN basis

Determines when space is allocated from the volume

Possible settings– enabled (default)

• Space is reserved from the volume at LUN creation time• This space is not available to other LUNs or files

regardless of how much is really used– Disabled

• No space is reserved from the volume at volume LUN time• Space is taken from the volume as data is written

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Fractional (space) Reservation

Set on a per volume basis

Determines if space is reserved from the volume at first snapshot creation

Possible settings– 100% (default)

• An amount of space equal to the amount of space used with in the LUNs is reserved from the volume

• This space is not available to other LUNs or files regardless of how much is really used

– 0 to 99% • An amount of space equal to the amount of space used

with in the LUNs times fractional_reserve is reserved from the volume reserved = LUN_SPACE * fractional_reserve

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Snap Reserve


Determines if space is allocated from the volume for Snapshot data at volume creation time

Possible settings– 20% (default for NAS) – 0% (current default for SAN) – 0% to 100%

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Snapshot Auto Delete

Set on a per volume basis Determines when (if) snapshots will be automatically

deleted Makes NetApp like competition but better Possible settings

– Triggers • Volume• Snap Reserve• Space Reserve

– Order• delete_order – oldest, newest• defer_delete – scheduled, user created, prefix, none• snapmirror/dump – try, disrupt

Snapshots locked by clones, cifs or restores will not be deleted – change planned for 7.3

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Volume Auto Grow


Determines if a volume should grow when it nearly full

Possible settings– ON

- Maximum growth- Increment size

– OFF

Try_first option determines whether auto_grow or auto_delete is attempted first

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Agenda



ONTAP Variables


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Space Management – Default Configuration

Default Configuration:– Guarantee = volume– LUN reservation = on – Fractional_reserve= 100%– Snap_reserve = 0% – Auto_delete = off– Auto_grow = off– Try_first = NA

Reserve

TestLUN

Available space

30GB

30GB

40GB

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Positives– Easy to manage/monitor space

• Running “out” of space only results in no additional snapshots being created

• SnapShots and active LUNs will always be available

– Volumes are independent of each other

Negatives– Requires 2X + Δ space requirement

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Default Configuration:– Guarantee = volume– LUN reservation = on – Fractional_reserve= 100%– Snap_reserve = 0% – Auto_delete = off– Auto_grow = off– Try_first = NA

Reserve

TestLUN

Available space

30GB

30GB

40GB

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Positives– Easy to manage/monitor space

• Running “out” of space only results in no additional snapshots being created

• SnapShots and active LUNs will always be available

– Volumes are independent of each other

Negatives– Requires 2X + Δ space requirement

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Agenda



ONTAP Variables


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Thin Provisioning – Snapshot Space – Autodelete

Auto Delete Configuration:– Guarantee = volume– LUN reservation = on – Fractional_reserve= 0%– Snap_reserve = 20% – Auto_delete =snap_reserve– Auto_grow = off– Try_first = snap_delete

TestLUN

Available space

20GB

50GB

30GB

SnapshotAvailable

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Thin Provisioning – Snapshot Space – Autodelete

Positives– Easy to monitor/understand space

just volume and .snapshot– Sacrifices snapshots before active LUNs– Volumes are independent of each other– Looks like the competition

Negatives– Doesn’t use shared space from the aggregate– Until ONTAP 7.3 have to be cautious with using

FlexClones

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Agenda



ONTAP Variables


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Thin Provisioning – Snapshot Space – Autogrow

Auto Grow Configuration:– Guarantee = volume– LUN reservation = on – Fractional_reserve= 0%– Snap_reserve = 0% – Auto_delete = volume– Auto_grow = on– Try_first = auto_grow

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Thin Provisioning – Snapshot Space – Autogrow

Positives– Uses shared free space from the aggregate for

possible growth– Sacrifices snapshots before active LUNs– Can tune amount of thin provisioning per volume– Works even with a smaller number of volumes

Negatives– Volumes are not completely independent of one

another• Always the case when using shared free space• Growth in one volume can limit growth of

another

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Thin Provisioning – Autogrow Example Volume Grow – Starting Point

Free, 30

vol1, 100

vol3, 100

vol2, 100

volume used / size / consumedvol1 = 0 / 100 / 100vol2 = 0 / 100 / 100vol3 = 0 / 100 / 100------------------------------------total = 0 / 300 / 300

free = 30

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Thin Provisioning – Autogrow Example Volume Grow – After volume growth

Free, 10

vol1, 100vol3, 100

vol2, 120

Single volume grows to 120GB


free = 10

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Thin Provisioning – Autogrow Example Volume Grow – After another volume grows

Free, 0

vol1, 110vol3, 100

vol2, 120

Single volume grows to 120GB

Another volume grow to 110GB

Aggregate is now full


free = 0

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Thin Provisioning – Autogrow Example Volume Grow – After freeing space

Space is freed within the volume- manual snapshot deletion

Volume is manually resized

Free, 10

vol1, 110vol3, 100

vol2, 110


free = 10

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Agenda



ONTAP Variables


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Thin Provisioning – Snapshot SpaceGuarantee = none

None Guarantee Configuration:– Guarantee = none– LUN reservation = on – Fractional_reserve= 0%– Snap_reserve = 0% – Auto_delete = volume– Auto_grow = off– Try_first = auto_delete

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Thin Provisioning – Snapshot SpaceGuarantee = none

Positives– Uses shared space from the aggregate

Negatives– Volumes are not independent of one another– Activity in some volumes can cause all volumes

with a none guarantee to go offline– Generally only makes sense with a large number

of volumes

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Thin Provisioning – Snapshot SpaceGuarantee = none - Example


free = 330

At volume creation no space is allocated from the aggregate

vol2, 0vol3, 0

vol1, 0

Free, 330

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free = 90

Free, 90

vol1, 40

vol3, 100

vol2, 100

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free = 0

Highlights both the advantage and disadvantage of a none guarantee– Allows vol2 and vol3 to use space which vol1 is not using– If any volume consumes more space all volume with a guarantee of

none are going to go offline on the next write

vol2, 120

vol3, 120

vol1, 90

Free, 0

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Thin Provisioning – LUNs – Guarantee = NONE

Guarantee = none configuration:– Guarantee = none– LUN reservation = on – Fractional_reserve = NA

(no snapshots)– Snap_reserve = 0%

(no snapshots)– Auto_delete = snap_reserve

(safety measure)

– Auto_grow = off– Try_first = snap_delete

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Thin Provisioning – LUNs – Guarantee = NONE

Positives– Uses shared free space from the aggregate– Works with SDW without issues

Negative– Limited by BURT 210149

Not possible to configure more a LUN larger than actual free space in the aggregate

• For example, aggregate has 200GB free and you create a 400GB volume

– It is possible to create 2 x 200GB or 4 x 100GB or 1000 x 100GB LUNs

– It is not possible to create 1 x 201GB LUN

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Agenda



ONTAP Variables


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Thin Provisioning – LUNs – reservation disabled

LUN reservation disabled configuration:– Guarantee = volume– LUN reservation = off– Fractional_reserve= NA

(no snapshots)– Snap_reserve = 0%

(no snapshots)– Auto_delete = snap_reserve

(safety measure) – Auto_grow = off– Try_first = NA

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Thin Provisioning – LUNs – reservation disabled

Positives– Volumes are independent of one another– Amount of thin provisioning can be tuned per

volume

Negative– Doesn’t currently work with SDW

• With Data ONTAP DSM 3.0, SDW is not needed for multipathing

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Agenda - Summary


fc06-053 thin provisioning for iscsi and fc

Documents

volume creation timethis

adequate space

usednoneno space

useddisabledno space

volume basisdetermines

lun creation timethis

volume lun timespace

volume creation timespace