External HDD or SSD for backups?

Started 5 months ago | Discussions
Fred Colon Forum Member • Posts: 86
Re: External HDD or SSD for backups?

Sean Nelson wrote:

Fred Colon wrote:

..continuously writes a log file to the SD Card evey few seconds ( unless you know and disable it). After 18 months of this it stopped working as the SD card had to many errors. A new card was the only solution to get it going again.

Because of this I have the OS in my PC running from an SSD and all data that needs frequent creation and modification on HDD.

It's a good idea to avoid SSD for heavily write-intensive files, but desktop drives are a lot more robust than SD cards because they're usually powered on for a much larger percentage of their lifespan. During idle periods the SSD's controller scans for marginal storage pages and rewrites or reallocates them. You also have the ability to look at the state of the drive's SMART counters to keep track of degradation before it becomes a real problem.

The underlying flash technology is the same for both SSD and SD cards.  Controllers for each may well differ.  Its more likely that SSD controllers implement wear leveling but its not certain that all SD card manufacturers will do this.

I don't think the fact that SSD cards are more robust because they are powered on more than SD cards is true.  In fact they would last longer if not powered on

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Ken60 Senior Member • Posts: 2,443
Re: External HDD or SSD for backups?
1

Fred I agree with you about the " grey cloud of forums " , but in honesty I have had drives fail of all kinds.    Internal HDDs that have been used for storage and left out of a PC and unpowered for a long time .  I now use the docking bay and pop internal HDD into it for backups.

One of the things I lost and was angry about was a Lacie D2 type external drive. It died and was presumed power supply , this was replaced and still nothing.  Drives were removed and read in a USB HDD unit and still unworkable ........ seems the storage was an OEM special and with the dead unit this was unworkable.   Also I found the drives used were a cr@ppy version little used by customers that could read their label . So can you really trust a box with claims of being great, and rugged, when you cant see whats inside or know in advance the issues at breakdown.

With my Startech USB , I decide the drives I use in it and select known reasonable drives. I decide the software used and format for data, and from usage to date I trust this more than other options.  As for the comments about handling , hell I have been handling HDDs for 30 years while building computers, and though I tempt fate none of my failures could be attributed to bad  handling.

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Gear ... what I need to get the job done , after all you don't see mechanics listing their brand of spanner as a qualification .

CAcreeks
CAcreeks Forum Pro • Posts: 15,837
Re: External HDD or SSD for backups?

Fred Colon wrote:

The underlying flash technology is the same for both SSD and SD cards. Controllers for each may well differ. Its more likely that SSD controllers implement wear leveling but its not certain that all SD card manufacturers will do this.

Unless you have evidence to the contrary, I don't believe any xSD cards (or USB thumb drives) implement wear leveling in hardware.

I don't think the fact that SSD cards are more robust because they are powered on more than SD cards is true. In fact they would last longer if not powered on

Well yeah, because writes are not occurring! But...

https://www.extremetech.com/computing/205382-ssds-can-lose-data-in-as-little-as-7-days-without-power

(I'm not endorsing that article, just offering it for discussion)

Sean Nelson
Sean Nelson Forum Pro • Posts: 14,038
Re: External HDD or SSD for backups?

Fred Colon wrote:

Sean Nelson wrote:

Fred Colon wrote:

..continuously writes a log file to the SD Card evey few seconds ( unless you know and disable it). After 18 months of this it stopped working as the SD card had to many errors. A new card was the only solution to get it going again.

Because of this I have the OS in my PC running from an SSD and all data that needs frequent creation and modification on HDD.

It's a good idea to avoid SSD for heavily write-intensive files, but desktop drives are a lot more robust than SD cards because they're usually powered on for a much larger percentage of their lifespan. During idle periods the SSD's controller scans for marginal storage pages and rewrites or reallocates them. You also have the ability to look at the state of the drive's SMART counters to keep track of degradation before it becomes a real problem.

The underlying flash technology is the same for both SSD and SD cards. Controllers for each may well differ. Its more likely that SSD controllers implement wear leveling but its not certain that all SD card manufacturers will do this.

I don't think the fact that SSD cards are more robust because they are powered on more than SD cards is true. In fact they would last longer if not powered on

The reason it's more robust when powered on is that the controller actively scans memory pages for problems and fixes them.   As the charge levels in the memory cells start to dissipate, the controller sees correctable ECC errors and can re-write the data to refresh it.

An SD card sitting on a shelf or in a powered off piece of equipment can't do that.   And even when an SD card is powered on I'm pretty skeptical that what passes for its controller would do any checking or recovery of any data that it's not specifically accessing to satisfy I/O requests.

Sean Nelson
Sean Nelson Forum Pro • Posts: 14,038
Re: External HDD or SSD for backups?

Fred Colon wrote:

Yes it would be good to get actual failure rate data rather than rely on what you read on forums. In my experience forums are full of people complaining about things and those with no problems seldom post just to say 'My widget works really well without any problems.'

My hard drives work really well without any problems.   But I still don't trust them.   To some extent the relative reliability is a moot point, because ultimately you can't trust any digital media, therefore you need backups, therefore you're covered if a certain piece of media fails.

So IMHO it's a wash from a data protection perspective.   And I think the overall reliability is good enough that it's not even worth worrying about from a lost time perspective, at least for the casual user.  If lost time is important to you then you need to be using redundancy for your online media, and again that pretty much makes relative reliability a non-issue.

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