NAS newbie to get very fundamental info

[CheapHomeServer]

Looking for basic NAS info. The amount of info on this site is overwhelming, but I think I can dig through it with a some direction.

My NAS goals:

- To be used heavily only very occasionally for video, audio and image storage and retrieval. The rest of my usage will be for random small files.​

- An inexpensive (slow ? I don't care!) home system for myself from an older desktop system replaced by a more modern one.​

- Single user.​

- Less than 20GB storage needed. I am making do with far less, but fast local storage, on-board NVME and external SSD's.​

- Any significant hardware upgrades would be on a new platform.​

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My technical background:

- Retired electronics design engineer.​

- Windows OS knowledge, only. Please don't throw things at me!​

- Can sort through large amounts of technical info.​

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Specific questions:

- Why are huge amounts of RAM desirable ?​

- Why are there Xeon-based systems popular ? ECC memory support ? Multiple physical CPUs rather than cores ?​

- The advantages of hardware RAID are obvious. Is motherboard-based RAID reliable and dependable ?​

- Why are hardware RAID adapter board prices so wildly varying ?​

- Why is a separate backup system desirable ? (Is this in case the primary system suddenly dies ? Can the backup system temporarily be used as the primary ?)​

- What does virtualization that provide ? Exactly what is virtualized ? What's the point ?​

- Are specific stable, well-supported (Debian) Linux versions recommended ? Keep in mind I only care about using TrueNAS, not the OS in general.​

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Observations:

- (Too) many articles claim it's easy to convert an old PC into a (simple home) NAS, but they inevitably get caught up in technical complexity when details are examined. I realize IX is a commercial company whose 'bread and butter' is corporate sales in which sophisticated (i. e. complex) systems are paramount.​

- I read that TrueNAS Core is destined be left to die a slow death due to neglect.​

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Many thanks in advance for helping me climb this info hill!

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[danb35]

The advantages of hardware RAID are obvious.

I don't think they are that obvious in 2024.

Is motherboard-based RAID reliable and dependable?

No, motherboard-based FakeRAID is neither reliable nor dependable. But software RAID can be both, and in the case of ZFS, which is what TrueNAS uses, it is.

I read that TrueNAS Core is destined be left to die a slow death due to neglect.

I'm sure iX would rather it not be phrased this way, but SCALE is definitely under more active development and seems likely to be around longer.

What does virtualization that provide ?

Virtualization provides virtual machines--they act like separate computers that can run completely different software--even a different operating system--than the host. They can be helpful for many reasons, including testing, or if you need to run software that runs under a different OS. For example, if you need to run a piece of software that only runs under Windows, you can install Windows (any version you like, at least back to XP) in a virtual machine and run that software there.

Why are huge amounts of RAM desirable ?

Mainly because ZFS caches as much as it can in order to improve performance.

 

[CheapHomeServer]

Thanks for the info. From my reading it wasn't obvious that ZFS provides software RAID capability. I thought it is just another file system variant, just being the near optimal for TrueNAS. I will have to investigate further.

Regarding virtual machines, I don't plan for this to be a do-all go-to machine, just a file server. No development other than to possibly download optional features/add-ons, but it seems this should be easy to do remotely, too.

Hardware:
- Since this will be relatively lightly used, is there any cost justification for expensive NAS grade hard drives ? Yes, they can provide sheer storage capacity, especially considering the cost/GB, but they are often described as very noisy. I'd like to tuck the system into a closet since it is 'headless' and access it remotely. Electricity cost will be negligible. Why not just use high capacity non-RAID 3.5'' drives ?

- Can the drives be allowed to spin down on time-out so to reduce their wear-and-tear ?

- How can the drives be physically connected ? SATA, eSATA, some kind of USB-C 3.2+ drive rack/case ? How is data connection usually done ?

 

[Arwen]

Thanks for the info. From my reading it wasn't obvious that ZFS provides software RAID capability. I thought it is just another file system variant, just being the near optimal for TrueNAS. I will have to investigate further.
...

Yes, ZFS is the RAID solution for TrueNAS. ZFS was designed by Sun Microsystems starting about 2000, to replace their existing main file system, UFS, but to also include volume management and RAID functions. In the process, Sun also wanted state of the art, (for 2000s), data integrity, which today is still one of the best file systems for data integrity.

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

...
Hardware:
- Since this will be relatively lightly used, is there any cost justification for expensive NAS grade hard drives ? Yes, they can provide sheer storage capacity, especially considering the cost/GB, but they are often described as very noisy. I'd like to tuck the system into a closet since it is 'headless' and access it remotely. Electricity cost will be negligible. Why not just use high capacity non-RAID 3.5'' drives ?
...

The NAS drive suggestion is based on multiple factors. One of the latest is that SMR, (Shingled Magnetic Recording), drives are found to be less than suitable for use with ZFS. Or even out right failures.

Other reasons to use NAS specific drives are these. Some non-NAS drives allow changing their parameters to NAS like.

• TLER, (Time Limited Error Recovery, some vendors use different names). Desktop or laptop drives make extreme effort to recover failing / failed blocks, even to spending more than 1 minute on the task, (at the expense of ANY other activity). NAS drives usually have TLER set to the minimum of 7 seconds because it is assumed RAID will take care of the failing / failed block.
• Head parking timeout. Laptop and some desktop hard drives will park the heads aggressively, like within 5 to 10 seconds of no activity. On a NAS server this can lead to 10,000s of head parks in mere months, causing wear on the head parking mechanism, long before the warranty expires. So NAS hard drives don't generally park their heads.

- How can the drives be physically connected ? SATA, eSATA, some kind of USB-C 3.2+ drive rack/case ? How is data connection usually done ?

For TrueNAS which uses ZFS exclusively for data storage, USB attached data drives are not recommended;

Why you should avoid USB attached drives for data pool disks

This subject has been coming up quite often in the last year or 2. Perhaps because of TrueNAS SCALE has brought forth some attention to TrueNAS in general and ZFS in specific. Please note that this is about USB attached storage for ZFS data...

www.truenas.com

In theory, you can use eSATA connections but, their is a cable limit and in some cases, speed limit of 3Gbits/ps. That can hurt a SATA SSD that is attached via eSATA. Plus, you are limited to 1 disk because SATA Port Multipliers are really not recommended, (see resource below).

You CAN use external disk enclosures using a HBA, (Host Bus Adapter), which has SAS external connections. But, except at the higher end, their are fewer SATA / SAS drive external enclosures that would seem reliable enough for a NAS server.

The most common TrueNAS setup is to use internal SATA drives, (HDD or SSD), with a case & power supply large enough to handle the amount of storage desired. And if the system board does not have enough builtin SATA ports, then an add-on HBA is generally recommended. (Instead of cheap, less NAS suitable, SATA expansion PCIe cards.)

Multiply your problems with SATA Port Multipliers and cheap SATA controllers

In the last year or two, we've had a resurgence of users asking about SATA Port Multipliers and cheap SATA controllers. Please, do NOT use port multipliers, and use cheap SATA controllers only after extensive research. SATA controllers and SATA...

www.truenas.com

There are plenty of other things, (quirks, limitations, etc...), about TrueNAS and ZFS that can make TrueNAS unsuitable for some people or their stated specific use case.

 

[CheapHomeServer]

Fortunately, the system has 4 SATA ports, no NVME slots, the spare video PCEe slot, room and power for a couple of 3.5 drives and spare peripherals for install. It looks like all I'll need to buy is Core and NAS-rated drives.

I'm surprised the cost of a brand new LSI 9220-8i 6G SAS HBA on ebay goes for less than $40 (no cables). Are there any advantages by going with this rather than relying on the built-in SATA ports ? Why are the ports (mini-SAS ?) on the HBA split into 4 SATA connectors ? Just to save connectors ? Will each SATA connection support 6Gbs throughput ? I read that SAS supports simultaneous 2-way data transfers.

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[danb35]

Are there any advantages by going with this rather than relying on the built-in SATA ports ?

Unless you were planning to run TrueNAS as a virtual machine (in which case you'd want to pass through an entire drive controller to that virtual machine), no; it's just additional cost (however nominal) and power consumption for no real benefit.

 

[Arwen]

...
Why are the ports (mini-SAS ?) on the HBA split into 4 SATA connectors ?
Just to save connectors ?
...

Yes. SAS is also is designed to support disk back planes that have multiple of 4 disks. Thus, cabling to such disk back planes is easier.

...
Will each SATA connection support 6Gbs throughput ?
I read that SAS supports simultaneous 2-way data transfers.

Yes, in general each SAS path supports 6Gbits/ps SATA throughput. SAS disks, (HDD or SSD), can go higher if both sides support higher speed, (SAS is up to 24G today and 45G being developed).

SAS does support bi-directional data transfers. BUT, SATA does not. When you wire a SAS HBA port to a SATA device, the SAS HBA turns the port into a SATA only port. So, half-duplex just like normal SATA motherboard ports.

SAS has a feature called SATA tunneling protocol. If you have a disk back plane with a SAS Expander chip, you can turn 4 or 8 SAS HBA ports into more, like 24 disk slots. Then, if you install SATA drives, the SAS Expander does the SATA conversion and tunnels the SATA protocol over SAS.

Basically, SAS was designed to accept SATA devices, (HDD or SDD).

 

[ChrisRJ]

@CheapHomeServer , I am not sure you really need a NAS. With 20 GB of storage, just use an SSD in your machine and do an encrypted cloud backup.