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Using USB Flash / Pendrives or [micro]SD cards for backup

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  Using USB Flash / Pendrives or [micro]SD cards for backup rhkramer@gmail.com - 2019-03-18 14:40 +0100
    Re: Using USB Flash / Pendrives or [micro]SD cards for backup Charlie Kravetz <charlie@keepingdreams.com> - 2019-03-18 15:20 +0100
    Re: Using USB Flash / Pendrives or [micro]SD cards for backup Michael Stone <mstone@debian.org> - 2019-03-18 15:30 +0100
    Re: Using USB Flash / Pendrives or [micro]SD cards for backup "Alexander V. Makartsev" <avbetev@gmail.com> - 2019-03-18 15:40 +0100
      Re: Using USB Flash / Pendrives or [micro]SD cards for backup "Thomas Schmitt" <scdbackup@gmx.net> - 2019-03-18 16:20 +0100
        Re: Using USB Flash / Pendrives or [micro]SD cards for backup Pascal Hambourg <pascal@plouf.fr.eu.org> - 2019-03-18 17:20 +0100
    Re: Using USB Flash / Pendrives or [micro]SD cards for backup Matthew Crews <mailinglists@mattcrews.com> - 2019-03-18 17:30 +0100
      Re: Using USB Flash / Pendrives or [micro]SD cards for backup Gene Heskett <gheskett@shentel.net> - 2019-03-18 18:20 +0100
    Re: Using USB Flash / Pendrives or [micro]SD cards for backup Ben Caradoc-Davies <ben@transient.nz> - 2019-03-18 18:20 +0100

#206307 — Using USB Flash / Pendrives or [micro]SD cards for backup

Is anyone (reading this list) using USB Flash / Pendrives or [micro]SD cards 
for backup?

I've thought about doing that, especially as they continue to come down in 
price, but my experience with them  at least in some cases has not been good.

The worst case seems to be dash cams where, after about a year or so they just 
stop working, but I've had at least one similar case using them for data 
storage.

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#206311

On Mon, 18 Mar 2019 09:30:13 -0400
rhkramer@gmail.com wrote:

>Is anyone (reading this list) using USB Flash / Pendrives or [micro]SD cards 
>for backup?
>
>I've thought about doing that, especially as they continue to come down in 
>price, but my experience with them  at least in some cases has not been good.
>
>The worst case seems to be dash cams where, after about a year or so they just 
>stop working, but I've had at least one similar case using them for data 
>storage.
>

I have been using SanDisk Ultra Flair 128GB USB 3.0 Flash Drive for
about a year. I have seen them fail, and when they do, it is immediate.
I use a different one each day, so if one fails, I still have a valid
backup available. I have had good luck with SanDisk drives, other
brands have not worked well for me.

-- 
Charlie Kravetz
Linux Registered User Number 425914
[http://linuxcounter.net/user/425914.html]
Never let anyone steal your DREAM.   [http://keepingdreams.com]

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#206312

On Mon, Mar 18, 2019 at 09:30:13AM -0400, rhkramer@gmail.com wrote:
>Is anyone (reading this list) using USB Flash / Pendrives or [micro]SD cards
>for backup?
>
>I've thought about doing that, especially as they continue to come down in
>price, but my experience with them  at least in some cases has not been good.
>
>The worst case seems to be dash cams where, after about a year or so they just
>stop working, but I've had at least one similar case using them for data
>storage.

yeah, they tend to just stop working randomly. on the other hand, any 
backup is better than no backup, so I'd advise using flash drives
until you have a better idea. (more than one; the odds of two dying at 
the same time as your primary disk are pretty low.)

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#206313

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On 18.03.2019 18:30, rhkramer@gmail.com wrote:
> Is anyone (reading this list) using USB Flash / Pendrives or [micro]SD cards 
> for backup?
>
> I've thought about doing that, especially as they continue to come down in 
> price, but my experience with them  at least in some cases has not been good.
>
> The worst case seems to be dash cams where, after about a year or so they just 
> stop working, but I've had at least one similar case using them for data 
> storage.
>
I would never consider these mediums to hold any important backups.
There are some reasons why they are cheap.
Mainly because they utilize cheap to produce NAND chips with extremely
low endurance ratios, like TLC or QLC.
But the main problem is, unlike SSDs, USB Flash Drives use controllers
without any kind of wear-leveling/wear-controlling and over-provisioning
technologies, that ensure the data gets evenly written across all NAND
cell blocks and prolong lifespan of every NAND cell block in
controllable fashion.
USB Flash drives write data anywhere as they see fit, so some NAND cell
blocks get more wear than others and could potentially fail at any time,
rendering filesystem unusable and making files partially corrupted or lost.
 

-- 
With kindest regards, Alexander.

⢀⣴⠾⠻⢶⣦⠀ 
⣾⠁⢠⠒⠀⣿⡁ Debian - The universal operating system
⢿⡄⠘⠷⠚⠋⠀ https://www.debian.org
⠈⠳⣄⠀⠀⠀⠀ 

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#206317

Hi,

Alexander V. Makartsev wrote:
> USB Flash drives write data anywhere as they see fit, so some NAND cell
> blocks get more wear than others and could potentially fail at any time,
> rendering filesystem unusable and making files partially corrupted or lost.

My way of using a rubber coated outdoor USB stick is to make incremental
ISO 9660 backups with encrypted file content. Only about 64 kB of previously
valid backup data get overwritten per backup. The bulk is written
sequentially so that the 10 year old 8 GB stick had only about a dozen of
total overwrites.
The probability is low that some physical blocks took a much higher
amount of overwriting.

But for indoor use i prefer Blu-ray media. Easier to stack.


Have a nice day :)

Thomas

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#206322

Le 18/03/2019 à 16:17, Thomas Schmitt a écrit :
> 
> Alexander V. Makartsev wrote:
>> USB Flash drives write data anywhere as they see fit, so some NAND cell
>> blocks get more wear than others and could potentially fail at any time,
>> rendering filesystem unusable and making files partially corrupted or lost.
> 
> My way of using a rubber coated outdoor USB stick is to make incremental
> ISO 9660 backups

You could also use UDF with VAT build (write once) or spared build 
(defect management), or "flash friendly" log-structured filesystems such 
as F2FS and NILFS.

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#206323

[Multipart message — attachments visible in raw view] — view raw

On 3/18/19 6:30 AM, rhkramer@gmail.com wrote:
> Is anyone (reading this list) using USB Flash / Pendrives or [micro]SD cards 
> for backup?
> 
> I've thought about doing that, especially as they continue to come down in 
> price, but my experience with them  at least in some cases has not been good.
> 
> The worst case seems to be dash cams where, after about a year or so they just 
> stop working, but I've had at least one similar case using them for data 
> storage.
> 

My advice: Don't do it.

Pendrives and Micro SD cards are not built for long term reliability.

If your data warrants backing up, use something built for longer term
storage, like a normal HDD or a tape drive.

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#206325

On Monday 18 March 2019 12:25:50 Matthew Crews wrote:

> On 3/18/19 6:30 AM, rhkramer@gmail.com wrote:
> > Is anyone (reading this list) using USB Flash / Pendrives or
> > [micro]SD cards for backup?
> >
> > I've thought about doing that, especially as they continue to come
> > down in price, but my experience with them  at least in some cases
> > has not been good.
> >
> > The worst case seems to be dash cams where, after about a year or so
> > they just stop working, but I've had at least one similar case using
> > them for data storage.
>
> My advice: Don't do it.
>
> Pendrives and Micro SD cards are not built for long term reliability.
>
> If your data warrants backing up, use something built for longer term
> storage, like a normal HDD or a tape drive.

And I much prefer a separate hdd and amanda, Recovery is about 10,000% 
faster when working from random access media instead of sequential 
access tape, and I dare say many times more dependable. My backup drive 
has been replaced several times, not because it failed unless you call 
too small a failure.  Currently keeping about 60 days worth on a 2T 
drive. And I've not lost a single bit in well over a decade now. YMMV of 
course, but backups is not anything I've lost sleep over in a long long 
time.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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#206324

On 19/03/2019 02:30, rhkramer@gmail.com wrote:
> Is anyone (reading this list) using USB Flash / Pendrives or [micro]SD cards
> for backup?
> I've thought about doing that, especially as they continue to come down in
> price, but my experience with them  at least in some cases has not been good.
> The worst case seems to be dash cams where, after about a year or so they just
> stop working, but I've had at least one similar case using them for data
> storage.

I have six 16 GB ext4-formatted USB 2 flash drives of two models that I 
rotate for daily local backups. Each backup is about a 3 GB 
gzipped-gpged-gzipped-tar file, so the write pattern is large sequential 
writes. The outermost zero-compression gzip ("pigz -0") allows a keyless 
32-bit checksum test with any gzip implementation. Each thumb drive 
contains no more than three backup files at a time. All are 
checksum-tested after each backup.

I have been using these drives for at least five, and perhaps more than 
seven years. My rough estimate is that I have written around 60 times 
their capacity to these drives. I have had one drive fail, about five 
years ago.

My rules for USB flash backup are: (1) nothing gets written to USB 
without first being encrypted because failed drives cannot be erased 
without physical destruction, and (2) nothing gets written to USB 
without a checksum because USB drives are unreliable and will happily 
and silently corrupt data.

Redundancy and the expectation of drive failure will reduce 
inconvenience when it occurs. And it will. But you have to be able to 
detect it.

I also have offsite backup in the cloud with the same encryption and 
integrity measures (plus cloud encryption), and retention of longer-term 
archival backups. Now that I have gigabit fibre, offsite backup is 
faster than local.

Kind regards,

-- 
Ben Caradoc-Davies <ben@transient.nz>
Director
Transient Software Limited <https://transient.nz/>
New Zealand

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