NAS OS Drives using DRAM-less SSDs, and it's overal performance

[Jimmyson]

I am making plans to build put together a NAS vault desktop, using some older spare hardware lying around. I picked up a system without any storage, so I would need to fill this up.
The board is in older Intel Z87, rocking a 4th Gen i5 CPU, a little overkill, but should be OK to start with. I plan to fill the machine up with large capacity HDD platter disks, aiming for 4-8TB for each drive, as I don't want to break the bank each time I purchase a small set.

 

Knowing that it's best practice to keep your OS and Data separate, I would need a boot/OS drive. A low capacity SSD, aiming for roughly 128-256GB would be more than enough. I don't plan to using SSD caching drives at present, but its worth considering. Note: NVMe is not supported on the motherboard due to not having one.

 

My question is in regards to the boot/OS drive. I can find a 240GB drive for A$40, while most other drives are around A$80. My guess for the low price is that it is missing a DRAM chip. I'm not sure if there is a way to check, as many vendors don't list/advertise in on their spec pages. My question is the performance impact and reliability of purchasing a DRAM-less SSD as a boot/OS drive.

 

I'm likely to use FreeNAS, (but unRAID, could be on the cards) with a ZFS format across any storage pool drives.

• How much wear would be placed on the OS drive for a NAS system?
• Would it suffer from SSD thrashing as big data comes in?
• Do cache drives offload this work from the OS SSD?
• Do these OS drives manage the cluster indexes?

As a side note, I don't plan to leave this NAS running 24/7. Its use case is primary archiving digital libraries and content, and a second tier back destination, between my long-term critical data on a portable HDD, and my on-demand server which runs NextCloud.

[Electronics Wizardy]

What model of ssd is this?

 

For a boot drive, dram won't matter at all. If reliability is a big issue, get 2 and raid 1 them. There won't be any data caching on these drives, and they will really only see io during bootup, updates, and very little io for logging.

 

For most gigabit home servers, don't bother with a cache ssd, it will be network limited anyways.

 

You can also boot from 2 usb sticks in raid 1. Should be more reliable, about the same price, and you have the sata bays still open for more hdds.

 

Also unraid is much easier to expand by adding a drive later on. It also works much better with mixed drive sizes.

[CerealExperimentsLain]

SSD, with or without DRAM will basically read just fine.  NBD.  People panic over DRAMless SSDs too much when there's plenty of situations they're fine for and frankly, unless you're doing something extreme, the practical impact will be minimal.

I have a 120GB Kingston A400 DRAMless SSD in my pfSense box, cause all it does is write settings and log files.
My Windows ME and Windows XP machines use the same drives.  I have a light usage Lenovo M93P Tiny that uses it.  They're fine.

Unless you're doing a lot of intense writing, I'd not even worry about DRAM much.  I'd not say use it as a CACHE drive in UnRAID.  Or in the OS drive in a high performance desktop.  But they're fine drives for casual usage.

[Jimmyson]

On 8/3/2021 at 1:58 AM, Electronics Wizardy said:

What model of ssd is this?

I am intially looking at the Crucial BX500 240GB 3D NAND SATA 2.5" SSD, size is overkill for either boot or OS drive. Reading some articles, maybe USB would be better for lower sizes, and I could pick up a couple USB header adapters, keep them tucked away.

 

21 hours ago, CerealExperimentsLain said:

Unless you're doing a lot of intense writing, I'd not even worry about DRAM much.

True, I was just initially unsure about the Read/Write cycles of a OS drive under FreeNAS or UnRAID, whether the IO index load of managing the ZFS pool was written to this drive. Seems from the messages thus fair, that may not be as extreme as thought.

 

I probs would expect some from of data/pool management stored somewhere though, just can't remember where...

 

On 8/3/2021 at 1:58 AM, Electronics Wizardy said:

Also unraid is much easier to expand by adding a drive later on. It also works much better with mixed drive sizes.

I do like what UnRAID offers, and considering that it's heavily pointed to in this community (and not for without reason), I am wanting to start with something free first. Get my bearings straight. UnRAID could be on the cards, but I would be paying for extra I don't plan to use, and mostly are operating elsewhere on other devices. See how my use case adapts.

[Electronics Wizardy]

3 hours ago, Jimmyson said:

True, I was just initially unsure about the Read/Write cycles of a OS drive under FreeNAS or UnRAID, whether the IO index load of managing the ZFS pool was written to this drive. Seems from the messages thus fair, that may not be as extreme as thought.

 

I probs would expect some from of data/pool management stored somewhere though, just can't remember where...

 

SO you want this drive to be a special device in ZFS?

 

By default those oses won't store any filesystem info on the boot drive. All the data/pool info is on the hdds by default

 

 

[CerealExperimentsLain]

3 hours ago, Jimmyson said:

I do like what UnRAID offers, and considering that it's heavily pointed to in this community (and not for without reason), I am wanting to start with something free first. Get my bearings straight. UnRAID could be on the cards, but I would be paying for extra I don't plan to use, and mostly are operating elsewhere on other devices. See how my use case adapts.

Not sure how this DRAMless thing applies to UnRAID though.  UnRAID runs off a flash drive.  Like it ONLY runs off a flash drive.

[Jimmyson]

18 hours ago, Electronics Wizardy said:

By default those oses won't store any filesystem info on the boot drive. All the data/pool info is on the hdds by default

 

18 hours ago, CerealExperimentsLain said:

UnRAID runs off a flash drive.  Like it ONLY runs off a flash drive.

Awesome! That defiantly puts my mind at ease! Looks like I can reconsider the need for the SSD, and just buy some low capacity USBs. Save the SATA ports, and not kill the flash chips .

As a side-note; if I do end up going down FreeNAS/TrueNAS Core solution with USB sticks, I would need to consider making adjustments to the System Dataset, as reported in TrueNAS's forum thread.

 

18 hours ago, Electronics Wizardy said:

SO you want this drive to be a special device in ZFS?

Not exactly sure on what a "special device" is for ZFS, and should follow-up on this.

[Electronics Wizardy]

5 hours ago, Jimmyson said:

Awesome! That defiantly puts my mind at ease! Looks like I can reconsider the need for the SSD, and just buy some low capacity USBs. Save the SATA ports, and not kill the flash chips .

As a side-note; if I do end up going down FreeNAS/TrueNAS Core solution with USB sticks, I would need to consider making adjustments to the System Dataset, as reported in TrueNAS's forum thread.

If you mirror 2 usbs, id just leave the install stock. It doesn't do that many writes, and you got a mirror if one dies anyways.

 

5 hours ago, Jimmyson said:

Not exactly sure on what a "special device" is for ZFS, and should follow-up on this.

basically a metadata cache, notneeded for this use case.