4TB disk recommendation.
 

One of the three disks in the ZFS array is going bad. The other two are keeping things working but I should replace them.

Can anyone recommend good models of 4TB SATA disks at a reasonable price? The market has changed since I last purchased any disks.


Currently looking at WD Red NAS drives.

The three old ones will be re-purposed, with the damaged sectors carefully mapped out and the remaining ones put to use in a monitored and non-essential filesystem.

Need to be careful with WD drives these days (actually all brands, but WD was/is worst offender) as you can end up with SMR ([URL="https://en.wikipedia.org/wiki/Shingled_magnetic_recording"]shingled magnetic recording[/URL]) drives instead of conventional magnetic recording drives. SMR can have awful write performance, especially during resilver operations.
I used to prefer IBM Ultrastar drives which then morphed into HGST Ultrastar, and finally got absorbed into WD. Since the integration, I've been using Toshiba N300 drives for 4TB and 8TB, as they have an uncorrectable read error rate of 1 in 10^15, while most competitors (and Toshiba's larger sizes) have 1 in 10^14 rates. Amusingly, the tech sheet lists it as 1 in 1015 and 1 in 1014 bits. Also rated for 24/7 operation and equipped with rotational vibration sensors and compensating algorithms.

[QUOTE=xilman;597421]The three old ones will be re-purposed, with the damaged sectors carefully mapped out and the remaining ones put to use in a monitored and non-essential filesystem.[/QUOTE]Discard that old thing. They only get worse over time. The effort to constantly babysit them, worrying about new problem sectors, isn't worth it IMO.

As for buying new ones: Just buy whatever is available. All the brands are the same. They all have good and bad models, but you won't know which is which until after the fact, so it is just a lottery anyway.

[QUOTE=xilman;597421]One of the three disks in the ZFS array is going bad. The other two are keeping things working but I should replace them.

Can anyone recommend good models of 4TB SATA disks at a reasonable price? The market has changed since I last purchased any disks.

Currently looking at WD Red NAS drives.

The three old ones will be re-purposed, with the damaged sectors carefully mapped out and the remaining ones put to use in a monitored and non-essential filesystem.[/QUOTE]

My QNAP NAS has 6 WD Gold Enterprise 4 Tb disks. I had to replace one yesterday as a weekly SMART test showed 8 questionable sectors. I keep a spare on hand and I ordered another which was $172 on Amazon. The failing disk had been running 24X7 for three years.

Erased the old one (one pass zeroes, took 24 hours) and took it to Staples for recycling.

[QUOTE=retina;597433]Discard that old thing. They only get worse over time. The effort to constantly babysit them, worrying about new problem sectors, isn't worth it IMO.[/QUOTE]

Seconded.

[QUOTE=retina;597433]As for buying new ones: Just buy whatever is available. All the brands are the same.[/QUOTE]

Respectfully disagree.

My personal sample set is relatively small. But there is one brand I will not touch (unless I have no other choice).

For larger sample-set considerations, I have always appreciated [URL="https://www.backblaze.com/b2/hard-drive-test-data.html"]Backblaze[/URL] publishing their empirical data.

And... Obviously... If you're doing local storage, mix in a blend of manufacturers and/or models into your RAID mix.

If you're doing cloud storage, it's a buyer's market. Just make sure you use at least two.

[QUOTE=retina;597433]Discard that old thing. They only get worse over time. The effort to constantly babysit them, worrying about new problem sectors, isn't worth it IMO.[/QUOTE]I tendto use such things as read-mostly devices holding material easily recoverable.

An on-line mirror of a CD and DVD collection is the standard use case.

[QUOTE=sdbardwick;597425]Since the integration, I've been using Toshiba N300 drives for 4TB and 8TB, as they have an uncorrectable read error rate of 1 in 10^15, while most competitors (and Toshiba's larger sizes) have 1 in 10^14 rates.[/QUOTE]Thanks. Been checking them out with mixed results. For instance a 1-star review at [url]https://www.scan.co.uk/products/4tb-toshiba-n300-hdwq140uzsva-nas-hard-drive-35-hdd-sata-iii-6gb-s-7200rpm-128mb-cache[/url] says
[INDENT][I][B]absolutely rubbish[/B]

Noisy and has now stopped working, this drive has hardly even had 6 months of use out of it and now nothing. I used to rate toshiba over the others but this is a waste of £100.[/I]
[/INDENT]Another review gives it 5 stars, though mentions the noise, and the third only 2 stars.

Not currently in stock at Scan, a company with which I have had good experiences in the past.

For ZFS, you absolutely want to avoid SMR. It will try resilvering to the drive, then fail once the drive fills up its CMR area and begins to rewrite to its SMR area.

WD Red [B]Plus[/B] are CMR. Seagate Ironwolf are also CMR. I'd pick one of those.

HGST Deskstar NAS is another option.

Just ordered a WD Red Plus from Scan. It was available for a couple of quid cheaper elsewhere but I have had very good experiences with Scan.

Thanks, all, for your advice.

Disk arrived, eventually. Courier's fault, not Scan.

Disk swap went easily but I had to RTFM to work out how to incorporate it into the raidz. Now resilvering smoothly and quickly.

The other two disks are both 2TB so, in some sense, I am wasting half the storage of the new disk. However, I expect those two to die before many years have passed and once both are replaced the full 4TB can be used(*). The price differential was tiny compared with the doubled capacity.

*Note to self: zpool set autoexpand=on backup