Managing storage capacity - FSx for Lustre

Managing storage capacity

You can increase the storage capacity that is configured on your FSx for Lustre file system as you need additional storage and throughput. Because the throughput of an FSx for Lustre file system scales linearly with storage capacity, you also get a comparable increase in throughput capacity. To increase the storage capacity, you can use the Amazon FSx console, the AWS Command Line Interface (AWS CLI), or the Amazon FSx API.

When you request an update to your file system's storage capacity, Amazon FSx automatically adds new network file servers and scales your metadata server. While scaling storage capacity, the file system may be unavailable for a few minutes. File operations issued by clients while the file system is unavailable will transparently retry and eventually succeed after storage scaling is complete. During the time that the file system is unavailable, the file system status is set to UPDATING. Once storage scaling is complete, the file system status is set to AVAILABLE.

Amazon FSx then runs a storage optimization process that transparently rebalances data across the existing and newly added file servers. Rebalancing is performed in the background with no impact to file system availability. During rebalancing, you might see decreased file system performance as resources are consumed for data movement. For most file systems, storage optimization takes a few hours up to a few days. You can access and use your file system during the optimization phase.

You can track the storage optimization progress at any time using the Amazon FSx console, CLI, and API. For more information, see Monitoring storage capacity increases.

Considerations when increasing storage capacity

Here are a few important items to consider when increasing storage capacity:

  • Increase only – You can only increase the amount of storage capacity for a file system; you cannot decrease storage capacity.

  • Increase increments – When you increase storage capacity, use the increments listed in the Increase storage capacity dialog box.

  • Time between increases – You can't make further storage capacity increases on a file system until 6 hours after the last increase was requested.

  • Throughput capacity – You automatically increase throughput capacity when you increase the storage capacity. For persistent HDD file systems with SSD cache, the read cache storage capacity is also similarly increased to maintain an SSD cache that is sized to 20 percent of the HDD storage capacity. Amazon FSx calculates the new values for the storage and throughput capacity units and lists them in the Increase storage capacity dialog box.


    You can independently modify the throughput capacity of a persistent SSD-based file system without having to update the file system's storage capacity. For more information, see Managing throughput capacity.

  • Deployment type – You can increase the storage capacity of all deployment types except for scratch 1 file systems. If you have a scratch 1 file system, you can create a new one with a larger storage capacity.

When to increase storage capacity

Increase your file system's storage capacity when it's running low on free storage capacity. Use the FreeStorageCapacity CloudWatch metric to monitor the amount of free storage that is available on the file system. You can create an Amazon CloudWatch alarm on this metric and get notified when it drops below a specific threshold. For more information, see Monitoring with Amazon CloudWatch.

You can use CloudWatch metrics to monitor your file system's ongoing throughput usage levels. If you determine that your file system needs a higher throughput capacity, you can use the metric information to help you decide how much to increase the storage capacity. For information about how to determine your file system's current throughput, see How to use Amazon FSx for Lustre metrics. For information about how storage capacity affects throughput capacity, see Amazon FSx for Lustre performance.

You can also view your file system's storage capacity and total throughput on the Summary panel of the file system details page.

How concurrent storage scaling and backup requests are handled

You can request a backup just before a storage scaling workflow begins or while it is in progress. The sequence of how Amazon FSx handles the two requests is as follows:

  • If a storage scaling workflow is in progress (storage scaling status is IN_PROGRESS and file system status is UPDATING) and you request a backup, the backup request is queued. The backup task is started when storage scaling is in the storage optimization phase (storage scaling status is UPDATED_OPTIMIZING and file system status is AVAILABLE).

  • If the backup is in progress (backup status is CREATING) and you request storage scaling, the storage scaling request is queued. The storage scaling workflow is started when Amazon FSx is transferring the backup to Amazon S3 (backup status is TRANSFERRING).

If a storage scaling request is pending and a file system backup request is also pending, the backup task has higher precedence. The storage scaling task does not start until the backup task is finished.