SAS Expanders vs. SAS (No Expander)

Technology Comparison

Price Comparison, Tower

Price Comparison, Rackmount

People are still buying SAS enclosures without expanders, especially small form factors such as the 1U 4-bay rackmount. As capacity gets closer to 16 drives, there is a clear trend towards SAS expander enclosures.

SAS Expanders

SAS (no expander)

High-capacity external enclosures.
16-bay 3U rackmount, 15-bay tower.
12-bay 2U, 24-bay 4U rackmounts.

Broader range of capacities.
(4-bay rackmount, 4-bay tower.)

SAS Controllers, expander enabled.
Requires a single external connector.

SAS controllers, any.
Require more connectors for more drives.

Can use SAS or SATA hard drives.

1 external cable per expander
(typically = 12, 16 or 24 drives)

1 external cable per 4 drives
(4 for a 16-bay enclosure)

No.

Yes, for internal connectors
(if no internal/external cable)

Cost more per enclosure.
Partially offset by less cost for cables & adapters.
Future enclosures will not require another controller.

compare the cost for tower or rackmount

Definitely costs less if you need fewer drives.
The cost gap narrows as you add more drives.

compare the cost for tower or rackmount

Theoretical bandwith is lower with less cables.
In practice, one enclosure, this is not material.
Could become an issue with larger arrays.

Most applications will not see a difference
between Expanders vs. No Expanders.

If you need (or will need) more drives
than your controller's connectors allow,
SAS Expanders provide the solution.

If you will not need a large number of drives,
SAS (without expanders) can be sufficient.

SAS Expanders

SAS Enclosures

Still have questions about SAS Expanders? PC PitStop has answers.