Whenever I truly need a "sector by sector" backup, I boot a
stand-alone linux image and use 'dd' to copy the data directly from the
raw device. -kb7psg
On Tue, 22 May 2012, Jack Brindle wrote:
> John;
>
> Be very careful with a sector-by-sector backup utility if you decide
> to use an SSD. Solid State Drives constantly are moving sector
> locations around in order to avoid writing to the same flash location
> too many times. This occurs whenever a file needs to be updated or
> rewritten, and is especially true of the directory sectors. Because of
> this a backup may catch a file relocation in mid move, or more often
> catch a directory update while it is being moved, The result will be a
> completely useless backup. We discovered this recently when a friend
> needed to restore his system from a backup.
>
> The answer is to use a normal file-oriented backup instead of a sector-
> by-sector backup. Those backups are very much useful when needed. With
> the trend to replace disks with SSDs, especially in laptops, this will
> become very important.
>
> For those wondering, TIme Machine is indeed a file backup and not
> sector-by-sector. I recommend it whole heartedly!
>
> Jack Brindle, W6FB
>
>
> On May 22, 2012, at 11:22 AM, John Ragle wrote:
>
>> Hi, Jim...
>>
>> There are several programs that make literal copies (mirror
>> copies)
>> of disk contents. This includes the OS and all program files as well
>> as
>> data...
>>
>> I happen to have been using one called "Macrium Reflect
>> Professional" for the last few years. It produces a bit-for-bit
>> literal
>> image (a mirror copy) of the TOTAL contents of one or more hard
>> drives,
>> and can re-load such images. It does much more than copy data files.
>> At
>> present, I am using a PC with 2 inboard hard drives, each of 250 GB
>> capacity. One of these is my WIN7 Ultimate OS and associated files
>> (including programs, etc), and is about 80 GB in total content. The
>> second is my Ubuntu 11.10 OS and a somewhat smaller collection of
>> files
>> (including programs, etc.) I back up the former almost daily onto a
>> 1 TB
>> external USB hard drive, and somewhat less frequently onto a Sandisk
>> 64
>> GB stick...the 80 GB on the C:\ drive fit nicely onto the 64 GB stick
>> with the compression used by Macrium. The rate-determining step in
>> these
>> USB-based devices is the USB transfer rate itself; 80 GB takes about
>> 25
>> minutes to back or restore, and I do it last thing at night, letting
>> Macrium close down the PC when finished.
>>
>> If I had a third drive bay, I would probably choose to back up
>> onto
>> a third drive...hard drives have become so inexpensive that you can
>> practically use them like floppy drives. This would be significantly
>> faster, about 10-12 minutes for the 80 GB contents of C:\
>>
>> A while ago, I used a Sparc 20 with a shoebox tape drive and "DAT
>> Tapes," but that had little to do with my ham radio operation. These
>> were unsatisfactory because the error rate was significant. I also
>> tried
>> using an elderly PC as a network server at home on our LAN. That too
>> was
>> somewhat cumbersome. My wife is an active software developer (vide the
>> "OWL" system from Cengage), and separately uses a version of Macrium
>> onto a 1 TB external drive, but much of her work is stored on a
>> corporate "cloud," and hopefully backed up there as well.
>>
>> I do not have a high opinion of "Windows Restore" -- it is
>> significantly more involved to use than is Macrium Reflect.
>>
>> An advantage (to me the most significant one) of doing a bit-image
>> backup is that when it comes time to restore program files (i.e. .exe
>> files, etc), one does not have to search out the distribution media
>> and
>> play "baking cookies" with those media for hours to rebuild the
>> system.
>>
>> A disadvantage of doing a bit-image backup is that in the absence
>> of good "garbage collection" one keeps using the same general
>> structure
>> over and over again...a case can be made for rebuilding from scratch
>> (not from the bit image) on a regular basis...some have suggested
>> once a
>> year, at least.
>>
>> The Linux crowd can tell you of several useful Linux based
>> utilities for total backup, restore, partitioning, etc...I won't
>> enumerate them here, though many of them are very useful.
>>
>> In general, I don't favor running anything off the "cloud." My ISP
>> is sometimes down for 1 or more hours, and that mode of dis-operation
>> would leave me in the cold. Moreover, in view of the spate of
>> successful
>> hacking attacks, I don't trust cloud security. If I disconnect from
>> the
>> internet, the only ways someone can hack me are via my WiFi or to
>> physically break into my home. I have taken pains to barricade the
>> former. The latter takes care of itself in the usual way.
>>
>> Hope this answers your questions....
>>
>> John Ragle -- W1ZI
>>
>> =====
>>
>> On 5/22/2012 12:59 PM, James Robbins wrote:
>>> John,
>>>
>>>
>>>
>>> Could you be more specific about your process for "bit image
>>> backup" and
>>> "safe sectors"? Program you use? What files you choose to
>>> backup? Whether
>>> Windows Restore program is or is not a suitable substitute? Thanks.
>>>
>>>
>>>
>>> 73,
>>>
>>> Jim Robbins
>>>
>>> N1JR
>>>
>>>
>>>
>>> "It is vitally important to practice "safe sectors." A bit image
>>> backup
>>> takes only a few minutes, and can be made on an auxiliary hard
>>> drive or a
>>> jump drive."
>>>
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>>>
>>
>> --
>> Sent from my lovely old Dell XPS 420
>>
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