How to Use the CISER Research Nodes:   Compression with NTFS

USING THE WINDOWS NTFS COMPRESSION UTILITY:

Please note before using:

• You may encounter an error when compressing very large files. For files over 500 MB in size, we recommend that you use gzip instead.

• CISER has tested files compressed by this utility with most of the software packages on CISER Research, and has encountered no problems. However, we cannot guarantee that all programs run on CISER Research will work on NTFS compressed files.

Compressing files:

1. Open the folder where you have the file(s) you want to compress.
2. Highlight the file(s) you want to compress. While they're still highlighted, right-click on one of them and choose "Properties". Click on the "General" tab, and notice how the number of bytes shown for "Size" and "Size on disk" are not very different.

3. Click on the "Advanced..." button.
4. Check the "Compress contents to save disk space" box, and click "OK".

5. Back in the "Properties" window, click "Apply". Notice how number of bytes shown for "size on disk" has significantly decreased. Click "OK".

Notes:

• Even though a file is compressed, the bytes shown in the folder are what the file would be in its uncompressed state. To visibly distinguish which files are compressed without having to check their properties, you can change a setting under "Folder Options":
  1. Go to Start->Settings->Control Panel->Folder Options.
  2. Click on the "View" tab.
  3. Check the first box which says "Display compressed files and folders with alternate color", and click "OK".

• This will make the file names of all compressed files a different color than uncompressed file names, when viewed from within a Windows folder. Unfortunately, this color setting is not carried across all nodes, so you will need to set each node that you want this to work on individually.
• If you want all the files within a folder to be compressed, you can right-click on the folder name instead of a file name. If you add or copy a file into a compressed folder, it is compressed automatically. If you move a file from a different CISER Research drive into a compressed folder, it is also compressed. However, if you move a file from the same CISER Research drive into a compressed folder, the file retains its original state, either compressed or uncompressed.
• Although this utility appears to allow you to use compressed files with software packages as if the files weren't compressed, what's actually happening is that the system is uncompressing the file each time you use it, and re-compressing it when done. If you plan to work on a compressed file more than one time per session, it would be beneficial to both you and the system for you to manually uncompress the file, work on it, and then manually re-compress it before logging off. This will save both your time and the system's resources.
• For files larger than 4 GB, there is some loss of stability and reliability when using Windows NTFS compressed files with SAS and other applications. If your file is very large, please uncompress it before using it and then recompress it when your done.
• Compressed files and folders cannot be encrypted.
• Additional information about Windows NTFS Compression may be found at: http://www.ntfs.com/ntfs-compressed.htm.