LSI 3108 Controller JBOD mode = IT mode?

[testcb00]

I have gotten an old supermicro 2U 12-Bay server case with a motherboard X10DRH-CT.
I see the Hot-swap backplane is a backplane with SAS expander, the on-board LSI 3108 is the SAS controller of this SAS expander.
I found that there is no IT mode on LSI 3108 but I found there are JBOD mode in the LSI 3108, is the JBOD mode equivalent to the IT/HBA mode in other PCIe SAS Card?
or I need to buy another PCIe SAS Card like SAS 9300-8i?

 

[Ericloewe]

No, it is not equivalent. It is supposed to work, but has not been tested in the same way IT mode has.

 

[testcb00]

ok, I will still use this on-board sas controller first. Hope it can work without data loss

 

[HoneyBadger]

Check to see if it will load and use the mrsas driver by default, or if that still has to be forced.

If not, try adding the tunables below as type LOADER

hw.mfi.mrsas_enable = 1 mrsas_load = YES

This is better supported but still not as well tested as the mpr driver for the SAS3008 cards.

 

[c77dk]

Have a blade (so no way of replacing controller) using this controller in JBOD mode and for me it works with the mrsas driver. SMART seems to be passed through just fine. Started out on 11.3-something and upgraded to 12.0 without issues.

 

[Shelha]

Have a blade (so no way of replacing controller) using this controller in JBOD mode and for me it works with the mrsas driver. SMART seems to be passed through just fine. Started out on 11.3-something and upgraded to 12.0 without issues.

Hello c77dk,

Like the OP, I recently purchased a Supermicro server with MB X10DRH-CT that has an onboard LSI3108 Controller. I was able to set the controller to JBOD mode and TrueNAS detected the 4 drives attached to the 3108 Controller, I am currently on TrueNAS version 12.0U7 and my objective is to run VMS on 4 -1TB SSDs (these are the drives connected to the controller), how did you load/force the mrsas driver and did you setup any tunables to ensure smooth operation? Any info you can provide will be greatly appreciated. Thanks!

 

[c77dk]

Like the OP, I recently purchased a Supermicro server with MB X10DRH-CT that has an onboard LSI3108 Controller. I was able to set the controller to JBOD mode and TrueNAS detected the 4 drives attached to the 3108 Controller, I am currently on TrueNAS version 12.0U7 and my objective is to run VMS on 4 -1TB SSDs (these are the drives connected to the controller), how did you load/force the mrsas driver and did you setup any tunables to ensure smooth operation? Any info you can provide will be greatly appreciated. Thanks!

I had no need to force or tune anything Just installed FreeNAS, and later upgraded to TrueNAS.
Just checked the tunables, and only have some for my network, which might not even be needed (they're from the FreeNAS days)

 

[rvassar]

Most of the problems you're likely to have with these controllers lie in the 1Gb of RAM they have on board, which the controller may try and use to optimize reads and interact with ZFS in odd ways. You might check and make sure your JBOD disks are configured with "nora" or "no read ahead" so the controller stays as much out of the way as possible. Certainly make sure there's nothing like "write back" set, though that would likely require a battery...

 

[jgreco]

We have a great resource on this topic. You really want to avoid MFI, and MRSAS is undesirable at best.

Please do go see:

What's all the noise about HBAs, and why can't I use a RAID controller?

1) An HBA is a Host Bus Adapter. This is a controller that allows SAS and SATA devices to be attached to, and communicate directly with, a server. RAID controllers typically aggregate several disks into a Virtual Disk abstraction of some sort...

www.truenas.com

 

[Shelha]

I had no need to force or tune anything Just installed FreeNAS, and later upgraded to TrueNAS.
Just checked the tunables, and only have some for my network, which might not even be needed (they're from the FreeNAS days)

Thank you very much for your response!

Most of the problems you're likely to have with these controllers lie in the 1Gb of RAM they have on board, which the controller may try and use to optimize reads and interact with ZFS in odd ways. You might check and make sure your JBOD disks are configured with "nora" or "no read ahead" so the controller stays as much out of the way as possible. Certainly make sure there's nothing like "write back" set, though that would likely require a battery...

This is very interesting and the more I think about it it may not be worth the effort given the fact that nowadays you can get a fully supported for a very reasonable price. Thank you so much for taking the time to respond!

We have a great resource on this topic. You really want to avoid MFI, and MRSAS is undesirable at best.

Please do go see:

What's all the noise about HBAs, and why can't I use a RAID controller?

1) An HBA is a Host Bus Adapter. This is a controller that allows SAS and SATA devices to be attached to, and communicate directly with, a server. RAID controllers typically aggregate several disks into a Virtual Disk abstraction of some sort...

www.truenas.com

Hello jgreco!! I know you respond to so many people so remembering every single user you interact with is quite difficult, but I just wanted to let you know that you were a great resource for me when I built my first FreeNAS machine quite a few years ago!!
Thank you so much for taking the time to respond and for the link, it was quite educational and it really helped me make the decision to not use the 3108 controller. Take care and talk to you soon! Cheers!