Dell PowerEdge R720XD config / pool design

[Probably Bob]

Hi all,

I'm almost ready to pull the trigger on buying the hardware for my first TrueNAS (Scale) server. I intend to use it as a replication target for regular backups from my main server (to be upgraded in a few months - in the meantime I will just be using rsync or somesuch).

I'm looking at a refurbished Dell PowerEdge R720XD 2U rack server with 12 3.5" bays in the front and two 2.5" bays in the back, configured as follows:

2x Xeon E5-2650 (8 core, 16 thread, 2.6GHz base, 3.4GHz boost)
8x 8GB 1600MHz DDR3L low power ECC RAM
H310 MiniMono RAID controller (which I will have to cross flash to HBA mode)
0C63DV NIC (I350 + X520; 2x 1G RJ45 + 2x 10G SFP+) <--- thanks to Ericloewe for pointing me to this

The OS will be installed on two mirrored SSDs in the two rear bays, which leaves me with the 12 3.5" bays in the front for the main storage pool. I can currently get hold of used 4TB WD Gold HDDs at a good price so I was thinking of the following:

3x VDEVS of four 4TB drives in RAIDZ2 each.

This would give me a total pool size of 24TB, which should be more than enough for the forseeable future (I would rather have the improved performance of the extra VDEV than another 8TB of storage). My plan is to have one brand new drive in each VDEV for peace of mind.

Does this look like a good setup? Any suggestions?

I gather there aren't any great requirements for the OS drives. Are basic consumer SSDs okay?

I'm working on the assumption that replication doesn't involve synchronous writes and I therefore won't benefit from a SLOG. Is this correct?

Cheers!

 

[HoneyBadger]

Does this look like a good setup? Any suggestions?

You look like you've got a good handle on the design philosophy here. I don't see any real omissions - you've got a plan to flash your H310. The only suggestion I might have is removing one CPU if you don't feel you'll need it (you likely won't) in order to save on power consumption, and maybe trying to obtain higher-density DIMMs (4x16G) - you shouldn't need all of the PCIe slots in the R720XD that the second CPU will enable.

I gather there aren't any great requirements for the OS drives. Are basic consumer SSDs okay?

There are some reported issues with the really cheap ones like the WD Green or similar that use the Silicon Image chipset - they fall offline but it might also be related to TRIM behavior. A pair of datacenter-pulled Intel DC S3500's is my current go-to for this.

I'm working on the assumption that replication doesn't involve synchronous writes and I therefore won't benefit from a SLOG. Is this correct?

ZFS replication does not involve sync writes, but if your interim solution of rsync is targeting an NFS export you may see them. Since you won't be designing around an SLOG long-term, you could set sync=disabled on the dataset and run async.

It looks quite nice though. Enjoy!

 

[jgreco]

Does this look like a good setup? Any suggestions?

My heart sinks every time I see "Dell PowerEdge R7xxx" in a subject line.

Then every now and then my faith in humanity is restored with a post like this, someone who did their homework. Or at least appear to have.

 

[Probably Bob]

You look like you've got a good handle on the design philosophy here.

Then every now and then my faith in humanity is restored with a post like this, someone who did their homework. Or at least appear to have.

That's reassuring. Thanks guys

The only suggestion I might have is removing one CPU if you don't feel you'll need it (you likely won't) in order to save on power consumption, and maybe trying to obtain higher-density DIMMs (4x16G)

Saving power on a CPU makes sense - especially at the moment! (I'm in the UK).

How much RAM do you think I will need for my use case? I thought 64G was probably overkill if anything(?)