Difference between revisions of "File system"

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== Snapshots ==
== User directories ==
 
 
 
== Snapshot functionality ==


Note that within your homedirectory, several states of your system  
Note that within your homedirectory, several states of your system  
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amended by the changes you make in bit-by-bit fashion.
amended by the changes you make in bit-by-bit fashion.


The folder that contains your particular snapshots is located in your homedirectory. It  
The folder that contains your particular snapshots is located in every directory an subdirectory of your homedirectory. It  
is a ''hidden'' directory that is also '''not''' visible if you list the content of your  
is a ''hidden'' directory that is also '''not''' visible if you list the content of your  
homedirectory via <tt>ls -la </tt>.
directory via
To make this as explicit as possible, to enter the respective hidden directory I
 
type within my homedirectory
  ls -la
   alxo9476@hero01:~$ cd .snapshot
 
Now, within that directory I find
To see the snapshots you have to enter the respective hidden directory by
 
   cd .snapshot
 
Within that directory the snapshots with timestamps are visible, e.g.
 
   <nowiki>
   <nowiki>
alxo9476@hero01:~/.snapshot$ ls
hpc_user_daily_2013-06-28_01-00
hpc_user_daily_2013-06-28_01-00
hpc_user_daily_2013-06-29_01-00
hpc_user_daily_2013-06-29_01-00
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hpc_user_weekly_recent
hpc_user_weekly_recent
   </nowiki>  
   </nowiki>  
I.e., snapshots of my homedirectory distinguished by the precise points in
 
time where they where taken. Within these folders you find the same
I.e., the snapshots distinguished by the precise points in
file-structure as in your homedirectory, of course!
time where they where taken. Within these folders you find the  
file-structure at the timestamp of the parent directory you are in.

Revision as of 09:53, 5 July 2013

User directories

Snapshot functionality

Note that within your homedirectory, several states of your system at particular points in time, termed snapshots, are available. In case you deleted or overwrote files accidentally, this comes in handy and can be used to restore the respective files as they appeared in previous versions. However, note that the term version is not fully correct: actually, the appearance of the files at previous times is stored and the available snapshots can be distinguished by means of their time-stamps. As a technical aside and from a more coarse grained point of view, note that a snapshot is not a full copy of your full data. Instead, from one snapshot to the next (in time), it is amended by the changes you make in bit-by-bit fashion.

The folder that contains your particular snapshots is located in every directory an subdirectory of your homedirectory. It is a hidden directory that is also not visible if you list the content of your directory via

  ls -la

To see the snapshots you have to enter the respective hidden directory by

 cd .snapshot

Within that directory the snapshots with timestamps are visible, e.g.

 
hpc_user_daily_2013-06-28_01-00
hpc_user_daily_2013-06-29_01-00
hpc_user_daily_2013-06-30_01-00
hpc_user_daily_2013-07-01_01-00
hpc_user_daily_2013-07-02_01-00
hpc_user_daily_2013-07-03_01-00
hpc_user_daily_2013-07-04_01-00
hpc_user_daily_recent
hpc_user_hourly_2013-07-03_20-00
hpc_user_hourly_2013-07-04_00-00
hpc_user_hourly_2013-07-04_04-00
hpc_user_hourly_2013-07-04_08-00
hpc_user_hourly_2013-07-04_12-00
hpc_user_hourly_2013-07-04_16-00
hpc_user_hourly_recent
hpc_user_weekly_2013-06-10_02-00
hpc_user_weekly_2013-06-17_02-00
hpc_user_weekly_2013-06-24_02-00
hpc_user_weekly_2013-07-01_02-00
hpc_user_weekly_recent
   

I.e., the snapshots distinguished by the precise points in time where they where taken. Within these folders you find the file-structure at the timestamp of the parent directory you are in.