IO profiles
You can optimize the performance of your Portworx volumes by matching the type of workload you're running with a suitable IO profile. IO profiles change the how a Portworx volume interacts with the underlying storage disks to improve traffic for different workloads.
If you don't provide an IO profile, Portworx will use the IO profile specified by the default-io-profile setting in the cluster. During Portworx spec generation, the default-io-profile option in the StorageCluster spec is set to auto by default. To change the default IO profile after installing Portworx, see the Change the default IO profile using pxctl section.
Understand the different IO profiles
The following are various IO profiles you can configure using the default-io-profile option:
autodb_remotejournalauto_journalnoneuse_cluster_default
The auto profile
This profile dynamically selects the optimal IO profile based on volume configuration, switching between none and db_remote for efficient IO handling. Portworx selects db_remote when a volume's replication factor is 2 or more; otherwise, it defaults to none. For single-replica (repl 1) volumes, auto applies internal optimizations to enhance performance without requiring manual adjustments.
The db_remote profile
This profile utilizes a write-back flush coalescing algorithm, reducing the number of sync operations by consolidating multiple syncs within a 100 ms window into a single operation. The coalesced syncs are acknowledged only after being copied to memory across all replicas, improving performance for highly available (HA) volumes. It is designed for repl 2+ volumes, effectively managing sync rates through periodic flushes.
- If there are not enough nodes online, Portworx will automatically disable this algorithm.
- The
db_remoteprofile only applies if you have a repl count of 2 or more.
The journal profile
To configure this profile for a volume, it is required to have a specific journal device or a dedicated partition allocated on the node. Follow the instructions on the Add a dedicated journal device to a node page to set up a journal device.
The journal IO profile ensures stable writes to a dedicated journal, batching commit operations to the backing pool. This reduces the overhead associated with frequent sync operations, making it ideal for database-class applications with high sync IO rates. It is particularly beneficial for single-replica (repl 1) volumes, efficiently handling high sync IO workloads by journaling both data and metadata.
The auto_journal profile
To configure this profile for a volume, it is required to have a specific journal device or a dedicated partition allocated on the node. Follow the instructions on the Add a dedicated journal device to a node page to set up a journal device.
The auto_journal profile continuously monitors incoming IO patterns and dynamically determines whether enabling the journal profile can improve performance. It evaluates write IO patterns over a 24-second window and automatically switches between the none and journal profiles based on detected workload behavior. This ensures journal mode is activated only when necessary, enhancing efficiency and performance.
The none profile
This profile disables all IO profile optimizations, processing all IO requests as they arrive without additional modifications. It is useful for workloads that do not require specialized IO handling.
The use_cluster_default profile
This profile allows the cluster-wide default setting to determine IO behavior, ensuring flexibility and consistency across multiple volumes. By default, the cluster is set to auto, but this setting can be overridden based on workload requirements.
Deprecated IO profiles
The following profiles are deprecated in the newer versions of Portworx.
The db profile
Databases typically result in a large number of flush operations on the disk. Because a flush forces Portworx to wait until the data is synched on the disk, it can slow down traffic. When the db profile is active, Portworx batches flush operations for a quicker write response time.
Legacy volumes will still show up as having db profile but internally they will be treated as auto profile volumes.
The sequential profile
This profile optimizes the read-ahead algorithm for sequential workloads, such as backup operations.
Legacy volumes will still show up as having sequential profile but internally they will be treated as auto profile volumes.
Configure profiles
You can configure IO profiles through Kubernetes specs or at the Portworx level, depending on your needs and what operator you're running with.
For information about how to configure IO profiles for volumes on Kubernetes clusters, follow this link:
Configure IO profiles for Portworx volumes on KubernetesFor information about how to configure IO profiles from volumes using pxctl, follow this link: