How to connect DELL PowerVault MD3260 as Direct Attached Storage (DAS)

[JaroslavH]

Hello,
I have DELL PowerEdge R720 server with TrueNAS. I would like to connect an MD3260 expansion unit to this server.
This unit is quite old and I don't have certified discs for it. I got a lot similar to the certified ones. The unit detects but does not accept them. So I can't use DELL SW (PowerVault Modular Disk Storage Manager). The possibility is, then I can access the unit as a direct attached Storage (DAS).
I have no idea how to access disks via TrueNAS.
In the R720 I have this controller: Dell SAS HBA 6Gbps PCI-e Dual Port SAS
I have these two cables for thisv 2x SFF-8088 to SFF-8088 External SAS Cable 2M
The DM3260 has the following controllers: 2x Dell PowerVault Disk Array Controller - E02M

How can I get this up and running?
Do I need to connect the SAS cable to SAS IN or SAS OUT? Do I need to install anything in TrueNAS? Do I need to set anything in the PowerEdge R720 BIOS?
Thanks in advance for your help.

 

[bakshuha]

Hi.
Dell MD3260 support only dell certified HDD.
You can see support disk there - https://downloads.dell.com/manuals/common/md32xx_md36xx_supportmatrix_en-us.pdf

 

[Ericloewe]

How can I get this up and running?

Assuming it will work at all, which I believe it should (but there's a decent thread about these things somewhere, 80% sure it's at STH), you just plug it in and use it. The disks should just appear "as normal".

Do I need to connect the SAS cable to SAS IN or SAS OUT?

SAS IN, SAS out is to daisy chain multiple chassis.

Do I need to install anything in TrueNAS?

No, you couldn't either.

Do I need to set anything in the PowerEdge R720 BIOS?

Simple answer: No. Long answer: Some minor configuration of the SAS HBA might be in order, but not for the chassis itself.

I have no idea how to access disks via TrueNAS.

Didn't you say you were already using TrueNAS? As far the OS is concerned, it's the same thing whether the disk is inside the server chassis or inside an external disk shelf.

 

[bakshuha]

Cable connection - https://downloads.dell.com/manuals/.../powervault-md3260_deployment guide_en-us.pdf

You need to create Disk Group, Virtual Disk, Host Group in PowerVault MD Storage Manager.

Add a port adapter from the server to the host group.

And assigning the number lun 0 for the virtual disk

Only then will your adapter on the server see this disk created in md3260.

There is no other way with dell md3260 )))

 

[Ericloewe]

If it does not support direct-attach disks without all that nonsense (which at least some Dell models do), then it’s not going to be adequate for use with TrueNAS.

 

[bakshuha]

If it does not support direct-attach disks without all that nonsense (which at least some Dell models do), then it’s not going to be adequate for use with TrueNAS.

Only through PowerVault MD Storage Manager

 

[jgreco]

The possibility is, then I can access the unit as a direct attached Storage (DAS).

No, it's been awhile since I've dealt with these, but I do not believe a non-controller option exists.

https://i.dell.com/sites/csdocuments/Shared-Content_data-Sheets_Documents/ar/dz/esg-Datasheet-PowerVault-MD3-Dense-Array-Mar14-Eng.pdf

The "controllers" on these are actually full SAN RAID controllers, and are not just simple SAS expanders. Because of this, there are firmware locks on the MD3260 that make the RAID CPU inside only accept the Dell drives. Even if this RAID system accepted non-Dell drives, it is not desirable for use with FreeNAS because of many of the same issues raised in the following article:

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

It can probably be made to work "not particularly well" with the Dell disks, and the set of steps kindly provided by @bakshuha sounds about right to me. Controller flooding is likely to be a significant problem (ZFS massive I/O rates can blow through the controller's cache).

As @Ericloewe mentions, some Dell storage arrays do offer non-RAID-controller options. These arrays will just have an SAS expander inside them and they will go to an SFF-8088 connector. These are usually compatible with random non-Dell disks. The shelves often sold as "expansion" shelves for a main RAID system like yours are also generally usable in this manner, though specifics vary.