Space Management Rick Jooss SANiSAN Business Unit.

Space Management

Rick Jooss

SANiSAN Business Unit

2Restricted to NetApp Employees & NDA Channel Partners. Copyright (c) 2006 Network Appliance, Inc. All rights reserved.

Agenda

What is Flexible or Thin Provisioning

Types of Thin Provisioning

How a LUN fills

ONTAP Variables

Space Usage in a volume

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


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



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


0% 25% 50% 75% 100%

File 1

Step #1 – write 2 files, each 25% of the LUN/disk size

Step #2 – write a 3rd file which is 25% of the LUN/disk size

Step #3 – delete files #1 and #2

File 2Host reports = 50% FullStorage reports = 50% Full

0% 25% 50% 75% 100%

File 1 File 2Host reports = 75% FullStorage reports = 75% FullFile 3

0% 25% 50% 75% 100%

Host reports = 25% FullStorage reports = 75% FullFile 3

Step #4 – write a 4th file which is 25% of the LUN/disk size

0% 25% 50% 75% 100%

Host reports = 50% FullStorage reports = 100% FullFile 3 File 4

LUN Filling with new files


Step #6 – delete file 3 and 4

0% 25% 50% 75% 100%

Host Reports = 0% FullStorage reports = 100% Full

0% 25% 50% 75% 100%

Host Reports = 25% FullStoragereports = 100% Full

Step #7 – add new file 5

File 5

LUN Filling with new files


LUN Fill Percentage versus Time

LUN Capacity Used versus Time

0%

20%

40%

60%

80%

100%

Time

% F

ull

LUNPercentageFilled


Agenda

What is Flexible or Thin Provisioning Types of Thin Provisioning ONTAP Variables Space usage in a volume Configurations

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


ONTAP variables affecting space usage

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


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


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


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


Available space

60GB

No Snapshots

40GB

LUN2: 20GB

LUN1: 20GB

Available space

20GB

At least one snapshot

fractional_reserve = 100

40GB

LUN2: 20GB

LUN1: 20GB



40GB Reserve

Available space

36GB

40GB

LUN2: 20GB

LUN1: 20GB

24GB Reserve

Fractional Reserve - Example


Available space

60GB

No Snapshots

40GB

LUN2: 20GB

LUN1: 20GB

Available space

20GB



40GB

LUN2: 20GB

LUN1: 20GB



40GB

Reserve

Available space

48GB

40GB

LUN2: 20GB

LUN1: 20GB

12GB Reserve

Fractional Reserve - Example


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%


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


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


Agenda




Available space

TestLUN

20GB

Step #1:Create “100GB” volume myvol

df output:/vol/myvol – available 80GB/vol/myvol/.snapshot – 20GB available

80GB

Available space

20GB

50GB

30GB

SnapshotAvailable

SnapshotAvailable

Step #2:Create 30GB LUN

df output:/vol/myvol - available 50GB - used 30GB/vol/myvol/.snapshot - available 20GB - used 0 GB

TestLUN

Available space

20GB

50GB

30GB

SnapshotAvailable

Step #3:Write 30(+) GB to TestLUN




Reserve

Step #4:Create snapshot #1


TestLUN

Available space

20GB

30GB

30GB

SnapshotAvailable

20GB

Reserve

Step #5:Overwrite first 10GB of TestLUN


TestLUN

Available space

10GB

30GB

30GB

Snapshot used

20GB

10GB Snapshot Avail

Reserve

Step #6:Overwrite second 10GB of TestLUN


TestLUN

Available space

20GB

30GB

30GB

SnapshotUsed

20GB



Reserve

Step #7:Overwrite last 10GB of TestLUN


TestLUN

Available space

10GB

30GB

30GB

Snapshot used



30GB

Reserve

TestLUN

Available space

10GB

30GB

30GB

Snapshot used30GB

Reserve

Step #8:Re-overwrite another 10GB of TestLUN


TestLUN

Available space

10GB

30GB

30GB

Snapshot used30GB



Reserve

Step #10:Overwrite first 10GB of TestLUN


TestLUN

30GB

30GB

Snapshot used

Step #12:Overwrite another 10GB of TestLUN


40GB

Reserve

TestLUN

30GB

30GB

Snapshot used

50GB

Reserve


Fails because there is no free space in the volume

TestLUN

30GB

30GB

Snapshot used40GB



Agenda




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


Space Management – Default Configuration

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


Agenda




Thin Provisioning Snapshot Space - Autodelete

Auto Delete Configuration:– Guarantee = volume– LUN reservation = on – Fractional_reserve= 10%– Snap_reserve = 0% – Auto_delete = volume– Auto_grow = off– Try_first = snap_delete

TestLUN

Available space

60GB

30GB

Reserve10GB


Thin Provisioning Snapshot Space - Autodelete

Positives– Easy to monitor/understand space

just volume – 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


Agenda

What is Flexible or Thin Provisioning


ONTAP Variables



Thin ProvisioningSnapshot Space – Autogrow

Auto Grow Configuration:– Guarantee = volume– LUN reservation = on – Fractional_reserve= 10%– Snap_reserve = 0% – Auto_delete = volume– Auto_grow = on– Try_first = auto_grow


Thin ProvisioningSnapshot 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


Autogrow Example - 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


Autogrow Example - After volume growth

Free, 10

vol1, 100vol3, 100

vol2, 120

Single volume grows to 120GB


free = 10


Autogrow Example - 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


Autogrow Example – 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


Agenda




Thin Provisioning Snapshot Space Guarantee = 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


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




free = 330

At volume creation no space is allocated from the aggregate

vol2, 0vol3, 0

vol1, 0

Free, 330




free = 90

Free, 90

vol1, 40

vol3, 100

vol2, 100




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



Agenda




Thin ProvisioningLUNs – 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


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 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

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


Agenda




Thin ProvisioningLUNs – 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 = on– Try_first = autodelete


Thin ProvisioningLUNs – 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

• Casablanca (May 2007) will support this!!


Agenda - Summary


Space Management Rick Jooss SANiSAN Business Unit.

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Transcript of Space Management Rick Jooss SANiSAN Business Unit.