[Klaus]

@JoJu - Of course, that is all your choice. :-) 

 

However, there's no way that your home managed storage can remotely compete in terms of reliability. It may be better with respect to availability though. Whether a reduced availability of 1-2h per year matters ... well ...

 

You may be right the regarding energy consumption. My drives are barely on. However ...

https://aws.amazon.com/about-aws/sustainable-energy/

 

Amazon has two data-center zones in Europe. It's a US company but whether your data goes to the US is a different question.

But I don't know the answer here :-)

[Rainer]

Thinking more, I think option 2 is the safe way to go. Does anyone know of software that can do that?

 

Depends a bit on your abilities of writing scripts yourself.

 

With "cygwin" (or even busybox or minsys) on a windows systems you can do the task with

a small set of simple commands:

 

Given you have a directory "DIR" on the internal drive that you want to

compare to the backuped dir BKUP-DIR on the external drive, you could run

 

cd $DIR

find . -name \* -print |

while read fname

do

   md5sum $fname

done >result1

...

do the same in BKUP-DIR (with redirection to result2)

and then

diff result1 result2

...

this should show missing files as well as additional files and

also files with different content.

 

Rainer

[JJ_SO]

Klaus, it's an American company. It's difficult to get by if you discover you're data abused.

 

Availabilty: I will never browse as fast through a hosted backup system as I can do at home. I will never rely exclusivley on a backup system somewhere in the internet. I have 10% upload speed as I have to download, so it takes ages to backup 2 TB once. So, this longer search periods you should add to the lack of availabilty. Handling altogether is slower, I suspect.

 

Another thing are the libraries of Aperture. Those are huge, so if I can't backup them in incrementals, I don't see myself waiting and leaving the Mac connected the whole night to Amazon servers. May backup systems do handle the incremental backup, but if I have to upload the whole lib after only a couple of changes - no way.

 

Depending on traffic, it also takes ages to download my files. How can I handle the preview? So I need to download folders and directories to get back one or a few files? The whole system is slow and out of reach if my router crashes or somebody hits a drill  or an ecavator shovel into the phone or fibre line. According to Murphy it's only a question when it will happen, not if.

 

I use two backups alternating so in case I overvwrite a good with a bad file, I still have one more drive.

 

At last, I don't feel safe putting my digital life out of my reach. Be it Amazon, Sony, Apple, Nokia - all of those services are vulnerable and had suffered several successfull attacks. I'm not scared about my rock-, trees-,  waterfall-pictures, it's just possible somebody could hijack the servers.

[popo]

I think here it depends a lot on what you expect of the cloud backup. Personally, I'm happy for it to be the 3rd copy, offsite. I will still keep two local copies, the live and a fast access backup. The cloud copy would be insurance against a site level disaster, and not something that would normally be accessed at all.

I'm also not that trusting, hence if if were to go this route, I'd only upload encrypted files in some form. Strong enough to prevent routine snooping anyway.


Back on my problems, I found 3 more corrupted files today. These were a little different, in that only part of the image is corrupted. Again in a hex editor, I'm seeing zeros where the missing data should be. This was only found as I left Picasa desktop running. This creates thumbnails quickly from the jpeg embedded in the raw, then slowly opens each raw to generate a better thumbnail from the full image. Here it becomes obvious when there is corruption as it is visible in the thumbnail.

[popo]

Ok, full paranoia mode enable. I'm now in the process of creating a full backup of the backup to ensure I still have 2 good copies of everything. Fortunately I never added any files to the 6TB disk other than what was on the backup, so I don't have to sort through it for new added files. I'm tempted to nuke it and make a fresh copy, on the assumption the copy was corrupted in some way.