4 4 3 Grolar:Configuring Si3 Deduplication Store

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Copyright © SEP AG 1999-2020. All rights reserved.

Any form of reproduction of the contents or parts of this manual is allowed only with the express written permission from SEP AG. When compiling and designing user documentation SEP AG uses great diligence and attempts to deliver accurate and correct information. However, SEP AG cannot issue a guarantee for the contents of this manual.

Docs latest icon.png Welcome to the latest SEP sesam documentation version 4.4.3 Grolar/4.4.3 Beefalo V2. For previous documentation version(s), check documentation archive.


SEP sesam provides a target-based (Si3T) and source-based deduplication (Si3S). For details on deduplication concept and recommendations, see Deduplication.

Both, Si3T and Si3S require a configured Si3 deduplication store. Only one Si3 deduplication store can be configured on a server. A valid licence is required for each Si3 deduplication store. Note that you can also configure an Si3 deduplication store by using a command line. For details, see Configuring and Administering Si3 Deduplication Store by using CLI.

You can download SEP Tachometer to analyse the structure of your data and calculate potential savings with SEP sesam Si3 deduplication. Check SEP Tachometer.


For the minimum Si3 hardware requirements that apply to SEP sesam Si3 deduplication server, see Hardware requirements. Keep in mind that these requirements represent the demand for deduplication only. In addition, the amount of memory for the operating system and other services should be taken into account.

In addition, the following prerequisites must be met to configure an Si3 deduplication store.

Additional RAM / CPU requirements

  • For details on the required Java version, see Java Compatibility Matrix. Si3 is not mandatory, therefore there is no dependency rule in the RPM/DEB packages for it.
  • When estimating the maximum size for a deduplication store, you have to ensure that there is enough space available for dedup trash or the deduplication store will run out of space. You should calculate the required disk space based on the representative sample of your full backup and add the amount of extra space equal to approx. 50% of the representative full backup.


To avoid issues arising from combination of too large Si3 deduplication stores and inefficient hardware, the maximum initial Si3 deduplication store size is restricted to 40 TB since Tigon V2 ( This restriction is valid when creating a new Si3 deduplication store in GUI. Note that customers with special requirements for larger Si3 deduplication store should contact SEP support to be able to increase the value up to an optimum size for their specific environments.

Required additional amount of RAM and CPU cores

The following tables show the required additional amount of RAM and CPU cores for one Si3 data store. The TB value is the capacity of the Si3 data store.

Information sign.png Note
It is not recommended to run Si3 deduplication (SEP sesam Server or RDS) on a virtual machine. If this is the case, like evaluation or test, consider to limit the capacity of Si3 data store to 100 GB thus ensuring normal VM operation. Have in mind that deduplication consumes a lot of server resources for reading, processing, and writing deduplicated data, therefore you should be aware of running Si3 on a VM deployment limitation.
Si3 data store capacity (check initial size restriction) RAM
<20 TB 16 GiB
20-40 TB 32 GiB

To find out how much RAM is required by Si3 at which capacity, enter the command sm_dedup_interface propose jvmconfig <Si3-CAPACITY> at an admin command line (you must set sesam profile to run the command). The MaxDirectMemorySize output is the required RAM value.

The following table shows the amount of CPU cores required for one Si3 data store. The TB value is the amount of backed up data (before deduplication)!

Backed up data (before dedup) CPU cores
10 TB 4
20 TB 4
40 TB 8
Information sign.png Note
Keep in mind that the stated requirements represent the demand for deduplication only. In addition to these requirements, the amount of memory for the operating system and other services should be taken into account.


The SEP sesam data store is a disk based storage that enables savesets (backed up data) to be backed up directly to the configured storage locations. SEP Si3 target deduplication is easily configured and ready to use by selecting Si3 deduplication data store type.

  1. In the Main selection -> Components, click Data Stores to display the data store contents frame.
  2. From the Data Stores menu, select New Data Store. A New Data Store dialog appears.
  3. Under the Data store properties in the Name field, enter a meaningful name for the Si3 data store.
  4. From the Store type drop-down list, select SEP Si3 Deduplication Store.
  5. New Si3 data store Beefalo V2.jpg

  6. Make sure that the option Create drive is checked under the Drive parameter properties. The predefined value for the drive is automatically added to the Drive number field.
  7. It is also recommended that the option Create second drive is checked. Without it, SEP sesam can only allocate a drive either for reading or writing, running one job at a time on the same drive. By using the additional dedicated drive for restore, you are able to run a backup on the first drive and restore your data from the second drive simultaneously. You can also add a third drive for migration.

  8. Then select Create new drive group and enter the name for your Si3 deduplication store dedicated group.
  9. The predefined number of channels is already displayed in the Max. channels drop-down list. The number of available channels depends on your SEP sesam Server package. For details on licensing, see Licensing.
  10. From the Device server drop-down list, select the device server for your data store.
  11. In the Path field, enter the location for your data store or use the Browse button to select the relevant folder. Check the relevant folder and click OK.
    When using the Browse button to select the folder, the New Data Store information window appears with predefined recommended values for your Si3 deduplication store size. Click OK to confirm the selected location and the recommended size values. You can modify your data store size later under the Size properties (see step 10).
  12. GUI new data store information Beefalo V2.jpg

  13. Under the Size properties, specify or modify the following:
    • Capacity: Specify the size (in GiB) of the partition for backups.
    • High watermark: Specify the value (in GiB) for the high watermark (HWM). The HWM defines the upper value for the used disk space on the data store. When this value is reached, a purge process is triggered for all EOL-free (End-of-lifetime) savesets, thus freeing up the capacity of the data store. The oldest free savesets are deleted first.
      Information sign.png Note
      In previous versions of SEP sesam (≤ Tigon), if HWM was set and exceeded, backups could no longer be started while running backups were allowed to finish. Purging is done until the low watermark is reached (if set). This behaviour has changed with SEP sesam v. ≥ Tigon V2; if HWM is set, exceeding it will only issue an information message but will no longer prevent backups to be started.
    • Si3 repair area: Specify the value (in GiB) for the Si3 repair area. The Si3 repair area (subdirectory trash) defines space for Si3 files (DDLs) that were identified by a garbage collection job and are no longer used. These files are still kept in the repair area to enable possible repair of Si3 if there are any structural problems (may be caused by a file system error or by a crash of an operating system). The files in the repair area will be removed automatically after the specified amount of time (SEP sesam default: 4 days) or when the disk usage threshold is reached. Note that when the value is set to 0, than the Si3 repair functionality is turned off.

    The Disk space usage properties are used by SEP sesam to report the following:

    • Used: Total used space (in GiB) on the partition.
    • Total: Maximum available space (in GiB) on the partition as reported by the operating system.
    • Free: Available disk space (in GiB) for SEP sesam.

You can view the properties of your Si3 deduplication by double-clicking relevant Si3 deduplication store.

  • You can modify existing and set additional drive options by double-clicking the first drive. In the Drive Properties window, you can browse the path for the data store. To configure Si3 data encryption, you have to create a deduplication security password file. For details, see Encrypting Si3 Deduplication Store.
    In v. ≥ 4.4.3 Beefalo, under the tab OS Access specify the credentials to access the respective systems. Use DOMAIN\USER format for domain accounts or HOST\USER for local accounts.
  • Si3 drive properties Beefalo V2.jpg

  • You can view the status of your Si3 deduplication by clicking the Si3 State tab. You can check the last deduplication message, status of active tasks, encryption status, number of stored objects, data size before/after deduplication, DedDup ratio, saved storage space, etc.
  • Si3 state tab Beefalo V2.jpg

Information sign.png Note
If fsck (file system consistency check) detects irregularity in the Si3 file system, the affected pages and chunks are recorded in the recovery.log. The Si3 deduplication store in GUI is marked red and the Si3 purge is no longer executed. The purge is stopped to prevent the files in the Si3 repair area to be deleted as they may be required to repair Si3 in case of problems. Once the errors are fixed and the recovery.log is empty, the Si3 data store is no longer marked red and the Si3 purge is working again.

Si3 deduplication store red.jpg

What is next?

After configuring the Si3 deduplication store, configure the media pools first then set up your backup strategy.