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SANtricity 11.5
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Functional comparison of pools and volume groups

Contributors

The function and purpose of a pool and a volume group are the same. Both objects are a set of drives logically grouped together in a storage array and are used to create volumes that a host can access.

The following table helps you decide whether a pool or volume group best suits your storage needs.

Function Pool Volume Group

Different RAID level supported

No. Always RAID 6.

Yes. RAID 0, 1, 10, 5, and 6 available.

Thin volumes supported

Yes

No

Full disk encryption (FDE) supported

Yes

Yes

Data Assurance (DA) supported

Yes

Yes

Shelf loss protection supported

Yes

Yes

Drawer loss protection supported

Yes

Yes

Mixed drive speeds supported

Recommended to be the same, but not required. Slowest drive determines speed for all drives.

Recommended to be the same, but not required. Slowest drive determines speed for all drives.

Mixed drive capacity supported

Recommended to be the same, but not required. Smallest drive determines capacity for all drives.

Recommended to be the same, but not required. Smallest drive determines capacity for all drives.

Minimum number of drives

11

Depends on RAID level. RAID 0 needs 1. RAID 1 or 10 needs 2 (requires an even number). RAID 5 minimum is 3. RAID 6 minimum is 5.

Maximum number of drives

Up to the maximum limit for the storage array

RAID 1 and 10—​up to the maximum limit of the storage array RAID 5, 6—​30 drives

Can choose individual drives when creating a volume

No

Yes

Can specify segment size when creating a volume

Yes. 128K supported.

Yes

Can specify I/O characteristics when creating a volume

No

Yes. File system, database, multimedia, and custom supported.

Drive failure protection

Uses preservation capacity on each drive in the pool making reconstruction faster.

Uses a hot spare drive. Reconstruction is limited by the IOPs of the drive.

Warning when reaching capacity limit

Yes. Can set an alert when used capacity reaches a percentage of the maximum capacity.

No

Migration to a different storage array supported

No. Requires that you migrate to a volume group first.

Yes

Dynamic Segment Size (DSS)

No

Yes

Can change RAID level

No

Yes

Volume expansion (increase capacity)

Yes

Yes

Capacity expansion (add capacity)

Yes

Yes

Capacity reduction

Yes

No

Note

Mixed drive types (HDD, SSD) are not supported for either pools or volume groups.