Tired of people losing data due to partition manipulation!

M

MrF

Gawd
Joined
Feb 18, 2009
Messages
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Every time one of these threads starts, it is too late to tell the poster that they should not have done what they did! The only option at that point is to use a data recovery tool hoping to get some of the data back.
So, I am starting a thread hoping to tell people how they can avoid the disaster.


:mad:
Please DO NOT use a partitioning tool (Partition Magic, parted magic, GParted, Disk Director, ...) to:
Move, resize from left, or merge a partition that contains data.
Any of these three modifications requires a temporary relocation of the contained data.
The relocation takes a long time (see post 15). If there is an error, there is no undo!


:)
Instead, DO:
From the OS, copy the data to a temporary location first.
Then, delete the partition(s) you are manipulating.
Then, create the partition(s) the way you want.
Now, again in your OS, restore the data to the modified partition.


WHY
The paritioning tool does all of it in one shot. This makes it a very risky function. If there is a single error in the data move phase, the whole function has failed. But, I have not seen any partitioning tool that can recover from such an error, or offer an undo choice.
If we break down each of the functions into logical phases and execute those phases in sequence, we have control over everything. If there is an error when we copy the data from a partition to another, the source data is still there. We have not deleted it yet. So, we can always attempt it again. More importantly, we have not lost the data.
 
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I've generally had good luck with partitioning software. With that said anyone who doesn't make a backup of their data before hand will only make that mistake once.
 
I've done the following:
defrag, defrag again, backup data (maybe), shrink partition. The first two steps are
imperitive AFAIK. If your data is valuable, the third certainly.
 
The problem isnt in any software, although as you have explained certain software is more prone to lose data than others, BUT in the end user. Face it, people will either 1) Back up, 2) Lose data , then learn to backup, or 3) Lose data. Period. It doesnt matter if you are partitioning, installing new programs, upgrading drives, etc, the ones who back up wont have the problems. I could throw my entire PC I am typing this on out the window, set it on fire, shoot it ; and not lose a single bit of irreplaceable data. So if anyone takes anything away from this is back up data you want to keep.


Edit ; Just wanted to add in, OP is correct, and it seems that repartitioning does seem to be the quickest way to screw stuff up.
 
You are right. I once messed around with partitions and almost lost data. The computer hung while Partition Magic did some operation, but I managed to repair it with "Testdisk", nice little program.
Now I always make backups and if I need a partition for linux testing or something, hell, I take a blank HDD.
 
Any 1/4 way tolerable partition management tool will have some kind of integrity check. YMMV, I can make no guarantees, but I've never suffered data loss from shuffling partitions around.
 
I use windows built in disk manager for partitioning, and I've never had a single problem.
 
^^^ exactly! that simple, if you got alot of data, then get alot of DVD's or another disk, period, end of it.
 
Partition Magic earned the nickname "Partition Tragic" because of the phenomenon described by the OP.

I always just buy bigger drives if I need to rearrange partitions :D
 
MrGuvernment said:
^^^ exactly! that simple, if you got alot of data, then get alot of DVD's or another disk, period, end of it.
Click to expand...

Then i'd need 2128 standard single layer DVDs to backup my 10tb. lol


Installing linux could end up in tragedy. One time, a few years back, I installed a distro on my file server. Told it to ignore the raid and install on the 300gb drive I had installed for linux. Went through the installation, everything seemed fine. I had some things left to do in windows, so I booted from the windows drive. I went to get a file from the raid and was greeted with a warning of how this drive was not formated or some shit. Turns out that the linux install, some how, corruped the gpt on the raid. Luckily it didnt damage all the partition data, just the first few bytes. But I couldn't get any utility to repair it, so I had to get one of those utilities to pull the data off of it. Many tears and long nights later, I had my data back.
 
The only time I've messed up a partition using one of these tools was when I used it on a fully encrypted drive, and that was only because the encryption software didn't like it.
 
i've lost some data by accidentally formatting a hard drive but not by resizing, i guess that i dont resize, i just copy the data off and then repartition it :)
 
NTFS data partition at the beginning of a 300GB SATA Seagate 7200.9 drive, containing a single 3.2GB file.
Shrunk the partition on the left (to add unallocated space before it) using GParted 4.5.2 live CD.

For a 5GB, 10GB and 25GB partition, the required time is 3.5, 8 and 20.5 minutes respectively.
Resizing an empty 5GB partition took exactly the same 3.5 minutes.
So, the time required to shrink on the left depends on the size of the partition and seems to be independent of the size of the data.

So, even if you have backups (which you should), you are still better off if you just copy the data in Windows, delete the partition and recreate it (quick format) where you want and then copy the data back to it in windows specially for a large partition.

Resizing on the right (affecting the unallocated space after the partition) is different and takes only about 5 seconds with GParted or with Vista or Windows 7 disk manager regardless of the partition size or data.

For a reference point, I did some copying in Windows on the same hardware.
Copying 10GB of data on the same drive took 7 minutes.
Copying 10GB from one physical drive to another took 3.5 minutes.
 
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I've never moved or resized a partition, just seems like asking for trouble
 
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