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Understanding CPU priority on inSync Client
Updated over a week ago

๐Ÿ“ Note
โ€‹This article applies to

  • OS: Windows, Mac, and Linux

  • Product edition: inSync Cloud and On-Premise


This article talks about the significance of setting up CPU priority for inSync Client.

In some cases, where you have huge outlook PST files backed up by inSync, you might experience system slowness issue. This is because of the large number of I/O requests on the disk which leads to high I/O read rate & high disk queue length even during incremental backups.

As a solution to this problem; we recommend to run inSync processes with low I/O priority which ensures disks are not thrashed out.

How does CPU priority work?

inSync 5.5 and onwards, inSync CPU priority is mapped to process I/O priority. When CPU priority is reduced either from inSync Management Console or by the user, it reduces the I/O priority of the process which in turn reduces burden on the disk.

If the end user does not have the option to change the CPU priority, it is possible the end user is not provided with the rights. In such cases, the inSync administrator has to enable the Modify backup resources option of the profile assigned to the user. The procedure is described in detail in the Allow users to update system resource settings for backups section of inSync documentation.

The following table explains how the mapping of I/O priority and CPU is handled:

Setting CPU Priority in profile on a scale on a scale of 0 to 10

CPU priority class

IO priority class



Very low for 0-1

Normal for 2


Below Normal






Above Normal


On inSync Client when a user sets CPU priority to Low, I/O priority changes to Very Low.

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