HBA IBM M1115 vs LSI SAS 9240

[phier]

Hello,
as per https://www.truenas.com/community/resources/hardware-recommendations-guide.12/ these two HBAs are recommended. Is it possible to say ibm is better then lsi or vice versa?

Also these are SAS2, and documentation mentioned SAS3 card.. is there some benefit using SAS3 instead of SAS2 in scenario where I use sata 3.5" drives?

thanks!

 

[nabsltd]

They are essentially identical, with only the BIOS being different. They can be cross-flashed into each other, so either one can be used:

LSI RAID Controller and HBA Complete Listing Plus OEM Models

Below is a list of all known LSI SAS devices from the SAS1068 chipset to the very latest not yet publicly available SAS3xxx series. Devices with links have been released and official website technical info/support. Quite a few devices with no links are devices that may have been going to be...

forums.servethehome.com

As for SAS2 vs. SAS3, if you are using direct connect (i.e., using a fan-out cable to connect 4 SATA drives to each connector on the card, then there will be no speed difference when using SATA drives, since SATA is capped at 6Gbps, which is SAS2 speed. If you use an expander, then it's unlikely you'll see any speed difference, either, until you have more (often a lot more) than 8 drives active at the same time.

 

[phier]

thanks, in that case SAS3 with SAS drives i assume is 6-12Gbps? thanks

 

[nabsltd]

SAS3 supports 12Gbps per channel. Any SAS disk you buy today (even used) is going to be at least SAS2 (6Gbps), but SAS3 really aren't any more expensive.

You still won't get any more speed per disk if you are using spinning rust, since event the fastest is around 2Gbps. But, SAS3 will help if you use an expander, since drives get multiplexed onto the SAS channels that are connected to the expander.

 

[phier]

hello,
what do you mean by "spinning rust" ?
i also assume you can use SAS3 without expander and directly connect drives from HBA? What expander do you mean?
thanks

 

[blanchet]

spinning rust is an ironic expression to says spinning disks
It emphasizes that spinning disks is an older technology than SSD.

Spinning disks are not rusted, it is just a slower but cheaper technology to store a very large amount of data.

 

[Redcoat]

spinning rust is an ironic expression

Nice pun!

 

[nabsltd]

Spinning disks are not rusted

Technically, the surface of the disk is (or at least was at one time) rust:

Urban Dictionary: Spinning Rust

Spinning Rust refers to a mechanical hard drive. Early hard disk drives had platters coated with iron(III) oxide, basically rust, hence the name.

www.urbandictionary.com