Compressing files - example

Last published : Jul 06, 2026
Storage Foundation 7.4.2 or later enables customers to use host-based compression to optimize existing primary storage. Enabling compression at the file system layer results in storage savings and avoids complex and expensive appliances typically associated with primary compression.
Compression is performed without needing any application changes and with minimal overhead. Compression does not modify the file metadata, nor are inode numbers or file extensions changed. Compression is executed out-of-band, after the write. Once compression is enabled, directories and files begin to have a mix of compressed and uncompressed data blocks. This is managed automatically by the file system, and uncompressed data is compressed during the next sweep.
See About file compression in InfoScale Operations Manager.
Using the InfoScale Operations Manager Management Server console you can enable file system compression and view the space savings.
Requirements for compression
Use cases for compression
Example of using compression in InfoScale Operations Manager
Requirements for compression
Compression has the following requirements:
  • InfoScale 7.4.2 or later
  • File System (VxFS) disk layout version 9 or later
  • InfoScale Operations Manager managed host (VRTSsfmh) version 7.4.2 or later
Use cases for compression
The following are some use cases for file compression:
  • Unstructured data
    • Studies indicate 90% of user-created data is never accessed after creation.
    • Increased regulatory restrictions leads to longer-term storage.
  • Oracle database archive logs
    • Oracle best practices recommend archive logs for database recovery.
    • As databases age and are used strictly for reads, log files go stale and unchanged.
How well a system handles the compression and uncompression of files is a key metric in deciding which data types can be compressed and when. Compression is CPU heavy and the CPU load should be considered carefully. Reading from compressed files can also result in performance degradation due to the increased I/O. The total space savings and time to compress or uncompress varies depending on server type, server load, file type, and compression settings. The following table shows some examples of possible savings.

Table: Compression savings

Data Type Platform Original Size Savings CPU Usage
Unstructured (80,000 files) Solaris SPARC 10 5 GB 70% 1 CPU: 6 %
4 CPU: 20%
Oracle archive log Linux RHES 18 GB 60% 1 CPU: 6 %
4 CPU: 20%
Example of using compression in InfoScale Operations Manager
In this example, a server administrator has a large set of seldom-used unstructured data in user home directories and will use compression to save storage space.
For examples of using compression with Storage Foundation from the command line, see the Storage Foundation Administrator's Guide.
The following object names are used in this example.

Table: Example names

Object Name
Host lnx_host
Volume vxvm_users
Mount point (file system) /home
The administrator performs the following procedures to reduce storage waste with file compression.
Locate the volume and mount point for the directories to be compressed
Add a compression schedule
Select the directories for compression
Verify the space saved by compression
To perform compression operations, you must have administrative privileges in InfoScale Operations Manager for the host on which you invoke the compression operation.
Locate the volume and mount point for the directories to be compressed
To locate the directories in InfoScale Operations Manager, you need to be able to identify the volume and mount point (file system) by name. The following procedure explains how to use the Management Server console to locate a volume and mount point for a host.
You can also use Search on the console menu bar to search for a volume and mount point.
To locate the volume and mount point
  1. In the Management Server console, go to the Server perspective and expand Manage in the left pane.
  2. Click Data Center and on the Hosts tab, type all or part of the host name to filter the list of hosts. For example, typelnx_host. Double-click the host name in the table. The host is highlighted and expanded in the tree.
  3. In the tree, under the selected host, click Volumes.
  4. On the Volumes tab, filter the list of volumes to locate the volume. For example, type vxvm_users.
Add a compression schedule
When selecting a schedule time and duration, keep in mind that compression is a CPU intensive procedure.
To add a compression schedule
  1. In the Management Server console, locate the volume and mount point.
  2. Right-click the volume on which the file system is mounted and click Properties.
  3. Click the Compression tab.
  4. Click Add Schedule.
  5. In the Compression Schedule window, specify the compression options and click OK.
    Frequency Select Daily , Weekly , or Monthly .
    When The options in the When area change depending on the Frequency selection. For Weekly , you can select weekday to schedule Monday through Friday or select specific days of the week. For Monthly , you can schedule the compression to re-occur on a specific day of every month.
    Compression Duration Specify how long the compression process runs. If all directories are not compressed during the specified duration, at the next scheduled compression run, the process continues with the remaining directories.
    For example, say that a duration of one hour is set and 10 directories are enabled for compression. After one hour, nine directories are compressed. The compression process stops. At the next scheduled run, the compression process continues with the tenth directory. The process then starts over with the first directory and compresses any new files that were added since the last run.
    Default: four hours
    Number of CPUs to use for compression Specify how many CPUs to use for the scheduled compression run.
    Default: 50 percent of the CPUs available for the host, up to 4 CPUs.
Select the directories for compression
You select which directories to compress for the selected file system.
To select the directories for compression
  1. In the Management Server console, locate the volume and mount point.
  2. Right-click the volume on which the file system is mounted and click Properties.
  3. Click the Compression tab.
  4. Select or deselect directories to enable or disable for compression. For example, select /home to enable all the user subdirectories under /home for compression.
  5. Click Apply.
The directories are compressed at the next scheduled compression run. If you want to run compression immediately, click Compress Now.
Verify the space saved by compression
You can verify the results of file compression by viewing the amount shown as Space Saved on the Compression tab once the compression run is complete.
You can also run a report to view top savings for file compression.
To view a report on savings by file compression
  1. In the Management Server console, go to the Server perspective and expand Reports in the left pane.
  2. With the Storage Utilization category displayed, click the Savings by File System Compression report.
  3. In the Select Scope to run report wizard panel, select the scope of the report and click Run.
More Information
Examples: Identifying and reducing storage waste using InfoScale Operations Manager