Which SSD as boot device?

[seldo]

Hello,

I'm finally close to moving to TrueNAS, I just miss a boot device.

I'm using a USB stick in my current system (with Nas4Free, running since ~2015) but I am moving to an SSD as recommended here.

I've been browsing extensively on which SSD drive to pick, without being able to find an answer.

1. It looks like 3D NAND and Marvell Controller don't play well.
2. Same goes for having trim enabled on some models: issues arise.

Is it still the case for 1. and 2.?

I was thinking of a WD Blue SSD 250GB (WDS250G2B0A), however it has 3D NAND & a Marvell controller.
I saw a couple of recommendations about the Kingston A400 (120/240): is this still a good pick one?
Crucial normally gets good ratings for PC usage, but I haven't read about them for NAS.
Does having DRAM cache in the SSD makes a difference for a boot device?

I understand performance is not a top requirement for this boot drive.
I just want to have something that's reliable enough so I don't get a failure that could have been avoided in a few weeks/months (namely, data corruption).

I don't plan to mirror my boot pool, however it looks like there is a script to make a backup of it.
It seems it is only about making a backup of the configuration file.

Thanks!

 

[HoneyBadger]

Unless I'm mistaken, the issues with corruption are with SiliconMotion (SM2xxx) series controllers. Marvell SATA controllers get badmouthed yes, but not the SSD ones.

Of the two I'd prefer the WD Blue, but you can easily pick up Intel DC S3500 80GB drives for $15-20 these days.

DRAM in the boot drive has no measurable impact on the performance though. Any SSD without a data-integrity bug will be fine. Honestly, even a laptop HDD would be fine.

 

[jgreco]

The Samsung 860 EVO 250GB's are like $40.

https://www.samsung.com/us/computin...sd-860-evo-2-5--sata-iii-250gb-mz-76e250b-am/

Nearly everyone concedes that Samsung makes some of the best SSD's out there, and if you buy a new 250GB SSD, failures are not impossible but are highly unlikely in my opinion.

There are lightly used options on eBay like the Intel DC S3500 as well, which are very robust and not that expensive. Small SSD's are not of much value in the modern data center so these often go for ridiculously cheap.

 

[sretalla]

I have seen no reports of issues with Kingston SSDs and have found them very cheap around where I am.

I have had bad experience with the WD green (3D NAND) SSD and I understand that the Blue variant may be based on the same chips, so watch out for that.

 

[seldo]

@sretalla : it might have been your post I've read about these WD green
Kingston's are also cheap here (30 euros for 240 GB).
The only thing I've read about the Kingston are the performances that are under other drives, but in the case of a boot pool, it doesn't matter much.

@jgreco : the 860 EVO are more expensive than the 870 EVO, and the main difference seems to be between the controllers.
(for 250GB: 860 EVO ~ 60 euros, 870 EVO ~ 40 euros)

@HoneyBadger : about the Intel DC SSDs, it would mean roaming the bay and hoping for a device with little wear. That could be a hit or miss.
Not that it's impossible, but I am not in the mood of getting into that. I just want to upgrade and finally be at peace with my system

So: for now, I'd say either a Kingston A400 240 GB or a Samsung 870 EVO 250GB
Anyway, I still have a couple of hours to think about it, I only get free delivery if I order past midnight.

 

[sretalla]

I'd say either a Kingston A400 240 GB or a Samsung 870 EVO 250GB

Agreed. I think you'll be fine with either.

 

[jgreco]

I've used the WD Blue SSD's for a lot of things, but not with a FreeNAS host. Prior to the December price drop on the Samsungs, they were my go-to option for cheap SSD. They work well with the LSI RAID controllers for ESXi datastores, and with Synology NAS units.

Samsung is (or was) dumping the 860 EVO's at a discount price. My biggest concern about the 870 EVO is that they haven't announced M.2 versions, or an 8TB unit.

 

[sretalla]

I've used the WD Blue SSD's for a lot of things, but not with a FreeNAS host

Just to reiterate, my use of WD Green SSD in FreeNAS was not OK. It uses one of the controllers that is subject to the TRIM problem and the OS had corrupt files showing up with every scrub.

I think the WD Blue uses the same controller, so I would recommend avoiding their use as boot SSDs on that basis.

 

[Patrick M. Hausen]

Transcend 370 series - still available in 32G and 64G. Have not had a single problem with them as boot devices.

 

[seldo]

It's going to be a pretty inactive system so I don't expect much happening on the boot drive.
I guess I could settle with 32/64 GB then.
@Patrick M. Hausen : I guess you have more activity on your NAS than me, so if you don't get errors, I shouldn't as well.
You have more ram than I do/can.

The only caveat I see at the moment is that I have 16 GB and will reach 26TB soon:
2*2TB mirror for scratch + 2*8TB mirror for coldstorage + 6 TB single drive backup... for now
So until I get RAM on eBay, I might have some swap.
I will be running with 16 GB of ram for 26TB of installed storage, which is much less than what I should.
The chipset doesn't support more than 8 GB / RAM slot.
That might trigger swap at some point, depending on the operations.
I will be having 12 TB of data (including mirrors and backup), and 14TB left empty for now.
I guess I will have to move machine when I reach 16 TB of data.
I won't be running dedup.

I might pick an SSD with a larger disk space to accommodate the wear caused by the (possible) swap.

So: Kingston A400 240 GB, Samsung 870 EVO 250GB or Transcend 370S 32/64GB
They all fit in the same price range too (30-40 euros).

I'm perplexed at what I should pick now.

 

[Patrick M. Hausen]

Device	TBW
Kingston A400 240GB	80
Samsung 870 EVO 250GB	150
Transcend 370S 64GB	180
Transcend 370S 32GB	90

I'd go for the Samsung or the 64GB Transcend ...

 

[seldo]

Since:

• I won't need more than 64 GB of swap (10 GB in the worst case),
• the Transcend 370S has the best TBW of all,
• it is known to work well for you,

looks like it is the Transcend 370S 64GB then!

 

[Patrick M. Hausen]

I would not put swap in the boot drive at all. Just keep a small partition on each of the data drives in your pool(s) as is already the default.

 

[seldo]

I would not put swap in the boot drive at all. Just keep a small partition on each of the data drives in your pool(s) as is already the default.

If found this: https://www.ixsystems.com/documentation/truenas/11.3-U5/storage.html?highlight=swap#swap-space

If I understand it right, when I will format, a partition is created on each of the drives that are redundant.
So if I have two pairs of mirrors, it will create a swap partition on 4 drives.
Does this swap partition affect the fragmentation in ZFS?
I'd say no, because it should be taken as a separate drive (though it might be running ZFS for it too).
Good it's automatically taken care of though.

I'm trying to have the least fragmentation on the coldstorage (I add but try to not remove & replace).

Seems like the Transcend uses a Silicon Motion controller: good that it works well.
So, despite the Silicon Motion controller and that the drive is a little old, if you say it works well for you, I'm inclined to take it.

 

[Patrick M. Hausen]

If I understand it right, when I will format, a partition is created on each of the drives that are redundant.
So if I have two pairs of mirrors, it will create a swap partition on 4 drives.

Yes.

Does this swap partition affect the fragmentation in ZFS?

No. The swap partitions are completely separate from ZFS. The default size of 2G per drive is a bit small for my tastes and experience. If you want to increase it, navigate to System --> Advanced and set the size before you create the pool. A setting of e.g. 16G will give you 32G of swap space - 2 mirrors of 16G each.

 

[seldo]

@jgreco : you used Samsung's SSDs in the past, but never as boot device. Correct?

 

[ChrisRJ]

I also happen to have a pair of Transcend 370S 64 GB drives as boot drives. They are even MLC and therefore relatively expensive. No issues so far.

 

[seldo]

y'all run on Supermicro boards
I hope it runs fine with my HP board

On to ordering the Transcend 370S 64GB then! I get it for $40 USD incl. VAT (converted)
Since I don't plan to reuse it (either it keeps running and I'm happy or it's dead and I replace it), performance & storage are only relevant for this NAS usage.

Thanks all!

 

[fmiz]

Hello, I'm a home user in a similar position as others here, I started running freenas with a USB flash boot drive and it is now starting to fail (in weird ways, disabling usb 3 support in bios has "fixed" it, at least for now). I have a longer question.
Instead of buying a 10€ usb flash drive and expect a failure in a few years, I will try to follow the "newer" recommendation and switch to a cheap SSD boot drive (with less than 30€). But I have no sata ports left in my system (x10slh-f with 6 4TB wd red in raidz2), so I've bought a cheap usb 3 to sata adapter I can find on amazon (made by sabrent, apparently).
After freenas added bhyve support, I started using it very lightly to run a few containers in a linux vm, it is mostly idle.
I've done some reading first to see if I can use some space of the boot drive to get some performance improvement for vm storage:
1) https://www.truenas.com/community/t...-of-larger-ssds-for-boot-pool-and-data.81409/
2) https://www.truenas.com/community/threads/the-path-to-success-for-block-storage.81165/
3) https://forums.servethehome.com/ind...ings-tuning-to-fix-slow-vm-sync-access.26688/
4) https://www.servethehome.com/buyers...as-nas-servers/top-picks-freenas-boot-drives/

My first thought has been to use the SSD also as SLOG for bhyve vdevs. I tested with fio as in [3] and as expected, changing sync to disabled instead of standard has performance benefits (to no one's surprise?), yet it is unclear to me what sync=standard does in a VM context (how does zfs decide to do a sync or async write?). After reading [2] and the fio result, I expect that a SLOG device can make a difference, but I have not tried testing with a ramdisk. Another thing that I could do is just store vdevs for bhyve on the ssd.
Now, I live in Europe and I can not find right now the kind of prices I've read around on the internet on used intel SSDs, the current best I have found on ebay is a used 160gb intel 320 for around 25€ shipped (I took advice from [4]), for the same price I can buy a new 128gb intenso ssd (a dramless thing with phison controller and a single flash chip with no endurance rating).
What should I go for in this case? An old, used intel 320 or a new cheap device? What I care mostly is avoiding the kind of failure I had with my current setup using a usb flash drive, everything else is just nice (and having an ssd with all that space unused looks like a waste to me).
Thanks for enduring to this point in this convoluted question.

 

[Etorix]

To avoid issues you may want to take a new SSD with a controller which is not SilliconMotion over a used Intel.

Consumer SSDs are NOT suitable for SLOG. A dedicated SLOG is only useful if you do sync=always, but performance is always worse than sync=never (and living with the risk). If you do invest in a SLOG, go for an Optane drive or a Radian RMS-200.