Looking to add additional drives externally.

[DCox88]

From what I understand, the primary connection methods are USB, eSATA, and SAS. I have read that USB can be unreliable.

 

I'm planning to have 4x 8TB drives stored externally, and I'm needing advice on the best way to connect them.

 

I am using a ASUS PRIME B660M-A D4, with a Fractal Node 804 case.

[JorgeB]

IMHO SAS is the only good option. 

[DCox88]

11 hours ago, JorgeB said:

IMHO SAS is the only good option. 

Care to elaborate?

[JonathanM]

eSATA has strict cable length limits, but can work if each drive has its own eSATA connection. Most eSATA enclosures have a port multiplier instead of individual links, so any operation involving more than one of the disks in the enclosure is going to be severely bandwidth limited. Parity checks would take forever.

 

USB can be problematic, as Unraid assumes a perfect drive connection and a normal USB reset will cause the drive to be dropped from the array. Also, many USB drive interfaces don't pass SMART data, some even mangle the hardware addressing, causing issues if you later want to move the drive to another connection.

 

SAS is the only protocol really meant to handle permanently server attached drives that Unraid expects.

 

There are other issues that I haven't covered with USB.

[DCox88]

4 hours ago, JonathanM said:

eSATA has strict cable length limits, but can work if each drive has its own eSATA connection. Most eSATA enclosures have a port multiplier instead of individual links, so any operation involving more than one of the disks in the enclosure is going to be severely bandwidth limited. Parity checks would take forever.

 

USB can be problematic, as Unraid assumes a perfect drive connection and a normal USB reset will cause the drive to be dropped from the array. Also, many USB drive interfaces don't pass SMART data, some even mangle the hardware addressing, causing issues if you later want to move the drive to another connection.

 

SAS is the only protocol really meant to handle permanently server attached drives that Unraid expects.

 

There are other issues that I haven't covered with USB.

Much appreciated for the information. Yeah, I guess I can understand how you USB would be problematic and maintaining a constant connection, so I think SAS is going to be the way to go.

 

To get a bit more information from you, I am mostly looking to store some drives externally because the size of my array is making it extremely difficult to work inside of the case.  What would I need for a deployment of four 3.5 in hard disk drives to connect to my PC via sas?

[JonathanM]

Read this entire thread, not just the first post.