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qospolicy modify

  • Updated on Aug 4, 2026
  • Published on Jan 28, 2026
  • 5 minute(s) read
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This command modifies a  QoS policy.

Usage

  • To modify a view QoS policy:

    qospolicy modify --id <ID>
                [--limit-by {BW_IOPS|BW|IOPS}]
                {
                    [--use-separate-limits] [--static-limits <LIMITS>] 
                  |
                    [--use-total-limits] [--static-total-limits <LIMITS>]
                }
                {
                    [--use-separate-limits] [--capacity-limits <LIMITS>] [--mode <MODE>] 
                  | 
                    [--use-total-limits] [--capacity-total-limits <LIMITS>] [--mode <MODE>] 
                }
                [--is-gold|--disable-gold]

  • To modify a user QoS policy:

    qospolicy modify --id <ID>
                [--is-default]
                [--attached-iam-roles <ROLES>]
                [--limit-by {BW_IOPS|BW|IOPS}]
                {
                    [--use-separate-limits] [--static-limits <LIMITS>] 
                  |
                    [--use-total-limits] [--static-total-limits <LIMITS>]
                }
                [--s3-connections-limit <LIMIT>]
                [--s3-conns-limit-per-cnode-pct <LIMIT>]

Required Parameters

--id ID

Identifies the QoS policy to modify.

General Options

--attached-iam-roles <ROLES>

Attaches a user QoS policy to one or more IAM roles.

Specify <ROLES> as a comma-separated list of IAM role IDs, for example: 2,5,8.

--is-default

When specified, the policy is used as the default user QoS policy for all users under the tenant specified in --tenant-id.

Caution

Specifying this option resets the list of users assigned to this policy.

--policy-type {VIEW|USER}

Determines whether the QoS policy provisions performance for views (VIEW) or users (USER).

--tenant-id <ID>

If the QoS policy is to be used for one or more users  (--policy-type USER), specify the ID of the tenant whose users can be assigned this QoS policy.  

Tip

To assign users to a user QoS policy, run the qospolicy attach-user command.

Options to Set Limits

--capacity-limits <LIMITS>

Enables and sets QoS limits per unit of used or provisioned logical capacity, depending on the provisioning mode (see --mode).

Specify <LIMITS> as a comma-separated list of key=value pairs, where the following keys can be used, depending on the --limit-by setting:

  • max_reads_bw_mbps_per_gb_capacity. Maximum read bandwidth to provision per GB of used logical or provisioned logical capacity, depending on the provisioning mode (set by --mode).

  • max_reads_iops_per_gb_capacity.  Maximum read IOPS to provision per GB of used logical or provisioned logical capacity, depending on the provisioning mode (set by --mode).

  • max_writes_bw_mbps_per_gb_capacity. Maximum write bandwidth  to provision per GB of used logical or provisioned logical capacity, depending on the provisioning mode (set by --mode).

  • max_writes_iops_per_gb_capacity. Maximum write IOPS to provision per GB of used logical or provisioned logical capacity,depending on the provisioning mode (set by --mode).

For example:

max_reads_bw_mbps_per_gb_capacity=1024,max_writes_iops_per_gb_capacity=2048

--capacity-total-limits <LIMITS>

Enables and sets QoS limits per unit of used or provisioned logical capacity, depending on the provisioning mode (see --mode), that cap the total amount of read, write and metadata operations.

Specify <LIMITS> as a comma-separated list of key=value pairs, where the following keys can be used, depending on the --limit-by setting:

  • max_bw_mbps_per_gb_capacity. Maximum bandwidth to provision per GB of used logical or provisioned logical capacity, depending on the provisioning mode (set by --mode).

  • max_iops_per_gb_capacity.  Maximum IOPS to provision per GB of used logical or provisioned logical capacity, depending on the provisioning mode (set by --mode).

For example: max_bw_mbps_per_gb_capacity=1024,max_iops_per_gb_capacity=2048

--limit-by {BW_IOPS|BW|IOPS}

Sets performance characteristic(s) by which to limit service:

  • BW_IOPS. Lets you set limits on both bandwidth (BW) and I/O per second (IOPS).

  • BW. Lets you set limits on bandwidth only.  

    Note

    When this option is specified, the options for setting IOPS limits are not used.

  • IOPS. Lets you set limits on IOPS only.

    Note

    When this option is specified, the options for setting bandwidth limits are not used.

--mode <MODE>

Determines how capacity-based limits are set.

Specify <MODE> as one of the following:

  • STATIC. No capacity-based limits are set.

  • USED_CAPACITY. Capacity-based limits are set based on used capacity.

  • PROVISIONED_CAPACITY. Capacity-based limits are set based on provisioned capacity.

--s3-connections-limit <LIMIT>

Sets the ​overall limit on S3 connections for the user​​. This limit restricts the total number of S3 connections that can be opened by the user to the VAST cluster (across all CNodes).

By default, no overall limit on S3 connections is set. '0' (zero) means that unlimited number of S3 connections is allowed.

--s3-conns-limit-per-cnode-pct <LIMIT>

Sets the ​CNode percentage limit on S3 connections for the user​​. This limit restricts the amount of CNode connection capacity that the user is allowed to consume, for any CNode in the cluster.

​NOTE: The CNode percentage limit can be set with VAST Cluster 5.4.6 and later.

​By default, no CNode percentage limit is set. '0' (zero) means that unlimited number of S3 connections is allowed per CNode.

--static-limits <LIMITS>

Enables and sets static QoS limits.

Specify <LIMITS> as a comma-separated list of key=value pairs.

The following keys can be used, depending on the --limit-by setting:

  • max_reads_bw_mbps. Maximum read bandwidth to provision, in MB/s.

  • max_reads_iops. Maximum read IOPS to provision.

  • max_writes_bw_mbps. Maximum write bandwidth to provision, in MB/s.

  • max_writes_iops. Maximum write IOPS to provision.

  • burst_reads_bw_mb. Burst bandwidth for read operations, in MB/s.

  • burst_reads_iops. Burst IOPS for read operations.

  • burst_reads_loan_mb. Maximum credit bandwidth for read operations, in MB/s.

  • burst_reads_loan_iops. Maximum credit IOPS for read operations.

  • burst_writes_bw_mb. Burst bandwidth for write operations, in MB/s.

  • burst_writes_iops. Burst IOPS for write operations.

  • burst_writes_loan_mb. Maximum credit bandwidth for write operations, in MB/s.

  • burst_writes_loan_iops. Maximum credit IOPS for write operations.

For example:

max_reads_bw_mbps=1024,max_writes_iops=2048

--static-total-limits <LIMITS>

Enables and sets static QoS limits that cap the total amount of read, write and metadata operations.

Specify <LIMITS> as a comma-separated list of key=value pairs.

The following keys can be used, depending on the --limit-by setting:

  • max_bw_mbps. Maximum read bandwidth to provision, in MB/s.

  • max_iops. Maximum read IOPS to provision.

  • burst_bw_mb. Burst bandwidth for read operations, in MB/s.

  • burst_iops. Burst IOPS for read operations.

  • burst_loan_mb. Maximum credit bandwidth for read operations, in MB/s.

  • burst_loan_iops. Maximum credit IOPS for read operations.

For example: max_iops=2048

--use-separate-limits

Disables total QoS limits, allowing you to apply separate QoS limits for read and/or write operations.

--use-total-limits

If specified, enables you to set limits that cap the total amount of read, write and metadata operations (see --static-total-limits and --capacity-total-limits).

Prioritization Options

--is-gold

Sets a prioritization flag for the QoS policy so that the workloads have higher priority in contention for CPU and memory resources. This option applies to view QoS policies only.

--disable-gold

Removes the prioritization flag from the QoS policy.

Example

vcli: admin> qospolicy modify --id 3 --mode STATIC --limit-by BW_IOPS --use-separate-limits 
 --static-limits max_reads_bw_mbps=1024,max_reads_iops=1024,max_writes_iops=2048

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