Freenas hardware upgrade questions.

[toddah]

I am currently running Freenas 11.x on a PC with (4 ) 3.5" 2 TB spinning disks for 4 years and recently had a disk failing so I created a new pool on a 4 TB disk and copied everything over as a safeguard.
I am going to upgrade hardware and hopefully increase my capacity at the same time. My plan is this
Add LI 9XXXX series HBA to the PC
Add a 8 disk SAS/SATA external enclosure connected to the HBA with a SATA splitter cable (sorry, don't know the terminology) for this.
Is this a supported configuration and are there any issues I should be aware of?
The expansion enclosure will house 3.5 or 2.5 disks (red NAS 4 TB)
Is there an advantage between 2.5 or 3.5 disks?

 

[smcclos]

Very simply size. 2.5 Disks stop at 2TB and if you can get them, they are extremely expensive. 3.5 disks are up to 22 TB and still offering larger storage capacities in the future.

 

[Davvo]

2.5 disks handle the spindown better and consume less power (which means they run colder)... but can be very noisy since they have to spin faster.

Laptop spinning rust drives have low mass platters to start spinning and laptop drives are designed to perform thousands of start/stop cycles.

3.5" drives are generally not near as robust when it comes to handling the surge of current repeatedly, as in a laptop drive. The 3.5" set of platters, especially for high capacity drives have a lot of mass and it takes a lot of current to spin those up. This repeated high current draw tends to overheat or just over stress the motor drive circuits and then you get the famous 'tick tick tick' of the drive head wanting to load but the drive isn't spinning fast enough or at a consistent speed, or just as bad, the drive doesn't spin up at all. Keep one thing in mind, the drive manufacturers only warranty a drive for 3 to 5 years (there are a few exceptions), so they build them to at least last for that period of time, then they expect the drive to fail so you can buy a new drive. They want to make money and if they designed a drive that would last 20 years, they would never make lots of money. Remember that. So if you take it easy on the drive start/stop cycle, especially if it's a large capacity drive, it will likely last significantly longer than the warranty period.

Regarding the external enclosure, you don't want anything (SAS expanders and backplates are and exception) between your HBA and those disks.
Regarding the cable, if you mean something like this it's fine.

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

Don't be afraid to be SAS-sy ... a primer on basic SAS and SATA

With the introduction of SAS 12Gbps, seems like "it's time" to do a braindump on SAS. Work in progress, as usual. History By the late '90's, SCSI and PATA were the dominant technologies to attach disks. Both were parallel bus multiple drop topologies and this kind of sucked. SATA and Serial...

www.truenas.com

I also suggest Seagate's Ironwolfs over WD's REDs.

 

[toddah]

The enclosure I am looking at has 8 sata plugs on the rear of the housing, I am assuming 1 for each disk.
Just diving into this tech so I not fluent in the interfaces yet.
Not sure what " sas expanders" are. So sort of multiplexing?

 

[Davvo]

Just diving into this tech so I not fluent in the interfaces yet.
Not sure what " sas expanders" are. So sort of multiplexing?

Read the two resources I linked, they will help (especially the second).

 

[toddah]

Read the two resources I linked, they will help (especially the second).

ThNk you for the education update. Changed my plans after reading them both