And would like to replace it. What would you recommend in the 1/2 to 1 Tb range for long term durability? An actual spinning HD or an SSD?

 

I've got a Seagate USB 4 GB drive that I use as my primary backup and it's been in use continuously for over ten years without a hiccup. Now, it could crash tomorrow. Also, the quality of Seagate USB drives a decade ago may not be indicative of their quality today. So take it as one piece of anecdotal information for what it's worth. The fact that, after about eleven years, I still have 3.5 GB of space available on it, despite having the final back ups from four other computers as well as my phone, makes me opt for reliability over capacity (higher capacity virtually always means that some reliability is being sacrificed).

 

That was my exact thought, and the reason I deliberately chose a storage capacity under 1Tb.
But my question was more about the reliability of a HDD vs a SSD?

 

But my question was more about the reliability of a HDD vs a SSD?

Most modern SSDs will be multilevel cells (3 or 4 bits per cell). Since flash loses charge over time, having to detect multiple charge levels in a cell implies that it's more likely that you'll encounter bit flips (vs SLC flash). I don't see how this is addressed in powered devices because charge loss will still occur and won't be "addressed" until a block is rewritten. I've seen guaranteed data retention time for unpowered devices as little as a year (it depends on P/E cycles, bits per cell, storage temperature, etc.).

A similar problem occurs with hard drives. Besides being mechanical, modern drives store data at a higher density than older drives, so there's less margin. A 1TB 2.5" drive will be more affected than a 3.5" drive.

That being said, I choose to use hard drives for offline storage. I usually have 4 copies of backups: where it was made, copied to another computer, and stored on 2 external hard drives. The external drives have been used for over a decade and are 2TB and 4TB. The 2TB drive is about half full. I would trust a hard drive more than an SSD to store data for a decade or more.

 

That was my exact thought, and the reason I deliberately chose a storage capacity under 1Tb.
But my question was more about the reliability of a HDD vs a SSD?

SSD, they have surpassed HDDs some time ago, overall, your more likely to get a failure with an HDD than SSD. But what are you backing up? why not just use the cloud (or Github for code)?

 

That was my exact thought, and the reason I deliberately chose a storage capacity under 1Tb.
But my question was more about the reliability of a HDD vs a SSD?

All digital storage is unreliable. It can, and does, fail at any time.

A HDD is a huge variation in reliability across the spectrum. For actual archival use, with a single drive (no RAID and NAS function), I would use WD Red class drives with a upgradable high quality external enclosure.
https://www.sybausa.com/shop/it-pro...ve-external-hard-drive-enclosure-sy-enc50125/

 

SSD, they have surpassed HDDs some time ago, overall, your more likely to get a failure with an HDD than SSD.

In terms of performance, yes. In terms of reliability, I think not. A hard drive used for long term backup won't be spinning constantly, so could retain data for many decades. I don't think the same could be said about flash.

why not just use the cloud

The cloud doesn't have as much privacy and security as a local storage medium. About the only reason I'd use the cloud is for sharing data.

Once something is stored in the cloud, you've lost control over how long data is retained and who can access it. Server farms have their own backup and retention methodologies. When I was a systems manager, I stored one monthly backup per year for many years. If you deleted something from cloud storage, you have no idea how many years it will still be available on backups.

 

I have the following spinning USB drives:

1. Seagate Free Agent Go PN: 9KW2AH-502 500 GB
2. Seagate Backup Plus Portable Drive PN: 1K9AP1-502 1 TB
3. Seagate Backup Plus Slim PN: 2R1APL 500 2 TB

The oldest and smallest one has been in service for over a decade. My primary computers all have 3 viable backup copies.

 

In terms of performance, yes. In terms of reliability, I think not. A hard drive used for long term backup won't be spinning constantly, so could retain data for many decades. I don't think the same could be said about flash.
The cloud doesn't have as much privacy and security as a local storage medium. About the only reason I'd use the cloud is for sharing data.

Once something is stored in the cloud, you've lost control over how long data is retained and who can access it. Server farms have their own backup and retention methodologies. When I was a systems manager, I stored one monthly backup per year for many years. If you deleted something from cloud storage, you have no idea how many years it will still be available on backups.

You might be right, he did state "backup". My PCs have SSDs and they have not suffered in any way for many years.

Back in the day we'd have a firm come over every night (this was the City of London) and collect backup tapes of vital financial positions. I guess these guys had some safe location for them - this was mid 80s.

One problem I see often with backups is people setup a backup strategy and procedures and run with that for years and then one day they need to restore and that's the step that is rarely tested and all kinds of issues sometimes crop up. Because a restore is rarely ever done it can fall victim to change, and when its needed there's a load of hassle and its sometimes even impossible.

One cannot have 100% confidence in any backup system unless they periodically test, like worst case test.

 

Back in the day we'd have a firm come over every night (this was the City of London) and collect backup tapes of vital financial positions. I guess these guys had some safe location for them - this was mid 80s.

When I was a systems manager (early to mid 1980's), I stored one copy on-site and one off-site at a company that specialized in storing tapes. I was in the SF Bay Area and the off-site storage was around Sacramento.

 

The fact that, after about eleven years, I still have 3.5 GB of space available on it, despite having the final back ups from four other computers as well as my phone, makes me opt for reliability over capacity (higher capacity virtually always means that some reliability is being sacrificed).

Could you explain?

 

Could you explain?

To get significantly higher capacities, you use smaller geometries or more aggressive multi-level storage, both of which reduce noise margins.

 

Excellent advice from everyone

 

Every computer I have ever owned has outlasted all the devices I bought on which to back it up.

 

Every computer I have ever owned has outlasted all the devices I bought on which to back it up.

My old raid media backup device finally died but the computer originally using it died long before.
https://forum.allaboutcircuits.com/threads/linux-at-home.191950/post-2032234

 

Since flash loses charge over time, having to detect multiple charge levels in a cell implies that it's more likely that you'll encounter bit flips (vs SLC flash). I don't see how this is addressed in powered devices because charge loss will still occur and won't be "addressed" until a block is rewritten.

SSDs utilizing multiple bits per cell all use error detection. When a block is determined to have too many errors, the block is marked bad and the data is rewritten to a block from the overprovision area. Presumably if the overprovision area is exhausted, a "regular" block would be used.

I've seen guaranteed data retention time for unpowered devices as little as a year (it depends on P/E cycles, bits per cell, storage temperature, etc.).

One SSD manufacturer recommended that unpowered SSDs be powered up (and somehow scanned/initialized) at least once a year to prevent data loss.

Additionally, the PE cycle limit on 5 bits/cell flash is 35 vs the more typical 100K cycles for SLC (and 1000 for TLC).