Reuse old drives, bad idea?

[eirik.lars1]

Well here we go again. Running out of space on my TrueNAS box. I currently have a 6x6TB raidz2 pool. Upgrading the disks to say 6x12TB wd reds would set me back around USD 2000 and double my usable storage space to 33 TiB. Thats a lot of money...

So I started thinking. I have 6x3TB wd red disks from my old storage pool gathering dust. And I'm waiting for an IBM M1015 HBA that I had planned to use for some extra SSDs to put the apps storage and VMs on. What if I put the 6x3TB disks in there also? With some fiddeling I could make them fit in my Fractal design R5 case. Problem is the disks are really old. Like 2016 old. And they have a lot of mileage on them as well. I did some calculations and I think my PSU (Seasonic focus GX 750 watts) should be able to handle the 12 disks + 4 ssds and all the other stuff in my case. But to put these disks as another vdev on my main pool where I keep irreplaceable stuff like photos and home videos is maybe a bad idea? I keep good backups of the irreplaceable stuff, but still. What about instead putting them on a separate pool and only use them for storing replaceable stuff like movies and series for plex on? Can I make plex see the media on both pools?

 

[eirik.lars1]

Anyone?

 

[Etorix]

750 W looks to be on the short side for 12 drives and "all the other stuff in [the] case".
Other than that…
12 TB is likely not the best price per TB now. Shucked WD have a sweet spot at 18 TB right now.
If you expect the old drives to die in a not-too-distant future, they are at best a stopgap solution while saving enough to buy another set of drives. With proper monitoring, it should not matter whether they are used as an extra vdev or as an extra pool with respect to data safety. The choice matters for the future of the pool: With an extra raidz2 vdev, there's no going down to 6 drives and a single vdev.

 

[Constantin]

Adding a second VDEV of old drives is a good stopgap while you set aside $$$ to upgrade drives in the future. Plus, it'll roughly double the I/O performance of your system. Assuming you have backups (including at least one off-site one), then there is relatively little risk in running a second VDEV of older drives. Ideally, you'd have cold, qualified spares for either drive capacity to quickly swap in, should there be a failure.

The obvious downside is higher power consumption, heat and the more difficult upgrade path, should you choose to shrink the # VDEVs / drives in the future.

I'd consider getting a used 3U or so SM server chassis with oodles of expansion room, upgrade the PSUs, and then run as many old drives as you need. The key to drive life is keeping their temperatures low, which is why I am not a great fan of most consumer cases. My A76 is a compromise given that I don't have a 19" rack to put a SM836 or whatever into. But it does a very nice job of keeping my 12 (?) drives cool and the PSU I'm using is only rated for 750W and the system consumes about 150W at max. That said, I am using He drives, so they idle / run at lower power.

 

[eirik.lars1]

750 W looks to be on the short side for 12 drives and "all the other stuff in [the] case".
Other than that…
12 TB is likely not the best price per TB now. Shucked WD have a sweet spot at 18 TB right now.
If you expect the old drives to die in a not-too-distant future, they are at best a stopgap solution while saving enough to buy another set of drives. With proper monitoring, it should not matter whether they are used as an extra vdev or as an extra pool with respect to data safety. The choice matters for the future of the pool: With an extra raidz2 vdev, there's no going down to 6 drives and a single vdev.

Thank you for your input.

Following jgrecos calculations in this post I came up with the following total potential watts for my system:

Drives: 12x35w = 420w
MB: 25w
CPU: 89w
RAM: 24w
HBA: 10w
Fans: 6,24w
SSDs: 16w
GPU: 30w
10GbE: 6,5w

= 624,74w

x1,25= 780,92w

Sooo, about 30 watts above my PSUs 750 watts. Is this correct and does the 30 potential watts mean my PSU is too small? I mean, I guess the CPU won't be using 89w during boot. So that would put me under 750 maybe?

Great deal on the shuckable 18TB easystores. I would totally go for that deal. Unfortunately they are not available in my countrly it seems. I did a quick search for external usb disks that are available locally but there doesn't seem to be any good deals like the one you linked to. Amazon has the WD elements 16TB but they only have 5 in stock. 6 of them would be 1930 USD including VAT and delivery to my location.

@Constantin Thank you for your reply also. You make good points about power consumption, heat and more difficult upgrade path. Ideally I would like to upgrade my 6 drive pool to keep it simple. But then there was the cost again...

Increased power consumption after adding the 6 3TB disks would be roughly 7-8 USD pr month with todays power prices. About heat and cooling I dont know. Maybe I would have to get new fans. With my current setup the drives are between 35-43 degrees celsius depending on ambient temperature. But these are relatively weak noctua fans. Getting stronger fans would however demand more wattage and money..soo. I don't know. Maybe its just a lot of work for not a lot of extra storage. I would get a server case but unfortunately I don't have the room for it.

 

[eirik.lars1]

Another option is to curate my media library to bring the storage on my current pool down. There is a lot of crap that neither I nor anyone else will ever watch again...

 

[Constantin]

Nothing wrong with adding old drives or deleting cruft. But if you add drives, keep an eye on the temps inside the fraktal case. Especially while resilvering or during a scrub. The XL+ was marinating my drives in their own juices at 50+ deg. C

 

[jgreco]

Sooo, about 30 watts above my PSUs 750 watts. Is this correct and does the 30 potential watts mean my PSU is too small? I mean, I guess the CPU won't be using 89w during boot. So that would put me under 750 maybe?

It probably won't kill you, but it DEFINITELY does not put you "under 750". The method I show of calculating is very conservative and allows for some safety margin at every step, so you are eating into the safety margin. As your PSU ages, it may be less able to sustain full load, or a variety of other things might also be competing to eat into that safety margin. This renders your system less able to cope with the unexpected, particularly in the future. It does not mean that you absolutely need 780 watts, it means 750 is a bit shy, 800 would be better if you could, but 500 is way too small.

 

[rvassar]

I found my solution was to run more than one pool. This gives me the flexibility to move things around. Not sure which TrueNAS version you're running, but you can usually edit the /etc/fstab in a Jail and mount an extra dataset. This can be on a different pool, but you'll find yourself having to split things up along the lines of "Music", "TV Shows", etc... Depending on how Plex has organized your media pool.

 

[Constantin]

Another aspect is that it is really difficult to find a quality titanium rated PSU at below 750W, if at all. I’d go with a Ti PSU, if possible as many a NAS will be operating in the lowest 25% capacity range for most of its life. In my case, it’s closer to 15%. That’s where a Ti PSU makes a difference. Then there is build quality.

 

[Etorix]

Great deal on the shuckable 18TB easystores. I would totally go for that deal. Unfortunately they are not available in my countrly it seems. I did a quick search for external usb disks that are available locally but there doesn't seem to be any good deals like the one you linked to. Amazon has the WD elements 16TB but they only have 5 in stock. 6 of them would be 1930 USD including VAT and delivery to my location.

I know the US deal does not apply to you, but the point is that the sweet spot in NOK/TB is probably also in the 16-18 TB area rather than around 12 TB, no matter whether you look at shuckables white label or plain NAS/enterprise drives. If you can actually triple the storage space for around 2000 USD (or better, the equivalent in crowns, spent on local retail and with local warranty), that may make the spending more acceptable.

With that, and assuming you can afford to buy 6 big new drives over the coming year, I'd be inclined to make a new pool with the old 3 TB drives—carefully watching temperatures, PSU behaviour and SMART reports—, begin buying 16-18 TB drives as opportunities arise and replacing the 6 TB drives along the way (so removed drives may serve as cold spares for the dubious old 3 TB). After the 6th new drive, consolidate everything to the much enlarged pool and decommission the 6*3 TB.
Pruning old cruft never hurts, of course.

 

[eirik.lars1]

I know the US deal does not apply to you, but the point is that the sweet spot in NOK/TB is probably also in the 16-18 TB area rather than around 12 TB, no matter whether you look at shuckables white label or plain NAS/enterprise drives. If you can actually triple the storage space for around 2000 USD (or better, the equivalent in crowns, spent on local retail and with local warranty), that may make the spending more acceptable.

With that, and assuming you can afford to buy 6 big new drives over the coming year, I'd be inclined to make a new pool with the old 3 TB drives—carefully watching temperatures, PSU behaviour and SMART reports—, begin buying 16-18 TB drives as opportunities arise and replacing the 6 TB drives along the way (so removed drives may serve as cold spares for the dubious old 3 TB). After the 6th new drive, consolidate everything to the much enlarged pool and decommission the 6*3 TB.
Pruning old cruft never hurts, of course.

Thank you. This sound like a good plan. I will wait for the HBA to arrive and then make another temporary pool only for movies and such. Then start to swap out the 6TB disks with 16-18TB disks probably sometime in the next year. If I get trouble with temperatures etc. I can easily just take them out without compromising my current pool.

Now, I need to fit the disks in there. Will look for a cheap mounting solution.

 

[eirik.lars1]

A follow up question on this one. My Seasonic psu has 4 connections for sata power. But in the package was only three cables. Two with 4 connections and one with two connections. So a total of 10 sata power connections. I cant get extra cables locally it seems. But I can get different sata power splitters. Do I need to get a dedicated cabel for the last port on the psu? Is it a bad idea to split the drives on the three ports?

 

[Etorix]

Bad idea indeed. Splitting means more drives, and more current, on the same cable and the same connector, which may go over specification.
Do you have other Seasonic PSU, which may use the same cables?
Have you inquired directly with Seasonic?

 

[eirik.lars1]

Bad idea indeed. Splitting means more drives, and more current, on the same cable and the same connector, which may go over specification.
Do you have other Seasonic PSU, which may use the same cables?
Have you inquired directly with Seasonic?

Ok, so I will not use the splitters. Will have to look for 2x cables with 4 connections to use all four ports on the PSU. I sent an email to Seasonic to see if they can help. Thanks.

 

[rvassar]

Splitting means more drives, and more current, on the same cable and the same connector, which may go over specification.

My first HDD back in 1986, a 5-1/4" Seagate ST238 had the same 4-pin molex connector on it that's still the basis for a modern ATX HDD accessory plug. It drew 35+ watts operating, vs 11 - 12 watts for a modern drive. I don't even want to think about the in-rush current...

Sometimes old specifications have benefits. I have no problem with splitters, but keep it reasonable. Added bonus, 4-pin molex to SAS/SATA omits the 3.3v that puts modern drives to sleep.