| title | description | author | ms.service | ms.topic | ms.date | ms.author |
|---|---|---|---|---|---|---|
Manage and update Azure HPC Cache |
How to manage and update Azure HPC Cache using the Azure portal or Azure CLI |
ekpgh |
hpc-cache |
how-to |
08/31/2020 |
v-erkel |
The cache overview page in the Azure portal shows project details, cache status, and basic statistics for your cache. It also has controls to stop or start the cache, delete the cache, flush data to long-term storage, and update software.
This article also explains how to do these basic tasks with the Azure CLI.
To open the overview page, select your cache resource in the Azure portal. For example, load the All resources page and click the cache name.
The buttons at the top of the page can help you manage the cache:
- Start and Stop - Resumes or suspends cache operation
- Flush - Writes changed data to storage targets
- Upgrade - Updates the cache software
- Collect diagnostics - Uploads debugging information
- Refresh - Reloads the overview page
- Delete - Permanently destroys the cache
Read more about these options below.
Click the image below to watch a video that demonstrates cache management tasks.
You can stop the cache to reduce costs during an inactive period. You are not charged for uptime while the cache is stopped, but you are charged for the cache's allocated disk storage. (See the pricing page for details.)
A stopped cache does not respond to client requests. You should unmount clients before stopping the cache.
The Stop button suspends an active cache. The Stop button is available when a cache's status is Healthy or Degraded.
After you click Yes to confirm stopping the cache, the cache automatically flushes its contents to the storage targets. This process might take some time, but it ensures data consistency. Finally, the cache status changes to Stopped.
To reactivate a stopped cache, click the Start button. No confirmation is needed.
[!INCLUDE cli-reminder.md]
Temporarily suspend a cache with the az hpc-cache stop command. This action is only valid when a cache's status is Healthy or Degraded.
The cache automatically flushes its contents to the storage targets before stopping. This process might take some time, but it ensures data consistency.
When the action is complete, the cache status changes to Stopped.
Reactivate a stopped cache with az hpc-cache start.
When you issue the start or stop command, the command line shows a "Running" status message until the operation completes.
$ az hpc-cache start --name doc-cache0629
- Running ..
At completion, the message updates to "Finished" and shows return codes and other information.
$ az hpc-cache start --name doc-cache0629
{- Finished ..
"endTime": "2020-07-01T18:46:43.6862478+00:00",
"name": "c48d320f-f5f5-40ab-8b25-0ac065984f62",
"properties": {
"output": "success"
},
"startTime": "2020-07-01T18:40:28.5468983+00:00",
"status": "Succeeded"
}
The Flush button on the overview page tells the cache to immediately write all changed data that is stored in the cache to the back-end storage targets. The cache routinely saves data to the storage targets, so it's not necessary to do this manually unless you want to make sure the back-end storage system is up to date. For example, you might use Flush before taking a storage snapshot or checking the data set size.
Note
During the flush process, the cache can't serve client requests. Cache access is suspended and resumes after the operation finishes.
When you start the cache flush operation, the cache stops accepting client requests, and the cache status on the overview page changes to Flushing.
Data in the cache is saved to the appropriate storage targets. Depending on how much data needs to be flushed, the process can take a few minutes or over an hour.
After all the data is saved to storage targets, the cache automatically starts taking client requests again. The cache status returns to Healthy.
To flush the cache, click the Flush button and then click Yes to confirm the action.
[!INCLUDE cli-reminder.md]
Use az hpc-cache flush to force the cache to write all changed data to the storage targets.
Example:
$ az hpc-cache flush --name doc-cache0629 --resource-group doc-rg
- Running ..
When the flush finishes, a success message is returned.
{- Finished ..
"endTime": "2020-07-09T17:26:13.9371983+00:00",
"name": "c22f8e12-fcf0-49e5-b897-6a6e579b6489",
"properties": {
"output": "success"
},
"startTime": "2020-07-09T17:25:21.4278297+00:00",
"status": "Succeeded"
}
$
If a new software version is available, the Upgrade button becomes active. You also should see a message at the top of the page about updating software.
Client access is not interrupted during a software upgrade, but cache performance slows. Plan to upgrade software during non-peak usage hours or in a planned maintenance period.
The software update can take several hours. Caches configured with higher throughput take longer to upgrade than caches with smaller peak throughput values.
When a software upgrade is available, you will have a week or so to apply it manually. The end date is listed in the upgrade message. If you don't upgrade during that time, Azure automatically applies the update to your cache. The timing of the automatic upgrade is not configurable. If you are concerned about the cache performance impact, you should upgrade the software yourself before the time period expires.
If your cache is stopped when the end date passes, the cache will automatically upgrade software the next time it is started. (The update might not start immediately, but it will start in the first hour.)
Click the Upgrade button to begin the software update. The cache status changes to Upgrading until the operation completes.
[!INCLUDE cli-reminder.md]
On the Azure CLI, new software information is included at the end of the cache status report. (Use az hpc-cache show to check.) Look for the string "upgradeStatus" in the message.
Use az hpc-cache upgrade-firmware to apply the update, if any exists.
If no update is available, this operation has no effect.
This example shows the cache status (no update is available) and the results of the upgrade-firmware command.
$ az hpc-cache show --name doc-cache0629
{
"cacheSizeGb": 3072,
"health": {
"state": "Healthy",
"statusDescription": "The cache is in Running state"
},
<...>
"tags": null,
"type": "Microsoft.StorageCache/caches",
"upgradeStatus": {
"currentFirmwareVersion": "5.3.61",
"firmwareUpdateDeadline": "0001-01-01T00:00:00+00:00",
"firmwareUpdateStatus": "unavailable",
"lastFirmwareUpdate": "2020-06-29T22:18:32.004822+00:00",
"pendingFirmwareVersion": null
}
}
$ az hpc-cache upgrade-firmware --name doc-cache0629
$
The Collect diagnostics button manually starts the process to collect system information and upload it to Microsoft Service and Support for troubleshooting. Your cache automatically collects and uploads the same diagnostic information if a serious cache problem occurs.
Use this control if Microsoft Service and Support requests it.
After clicking the button, click Yes to confirm the upload.
The Delete button destroys the cache. When you delete a cache, all of its resources are destroyed and no longer incur account charges.
The back-end storage volumes used as storage targets are unaffected when you delete the cache. You can add them to a future cache later, or decommission them separately.
Note
Azure HPC Cache does not automatically write changed data from the cache to the back-end storage systems before deleting the cache.
To make sure that all data in the cache has been written to long-term storage, stop the cache before you delete it. Make sure that it shows the status Stopped before deleting.
After stopping the cache, click the Delete button to permanently remove the cache.
[!INCLUDE cli-reminder.md]
Use the Azure CLI command az hpc-cache delete to permanently remove the cache.
Example:
$ az hpc-cache delete --name doc-cache0629
- Running ..
<...>
{- Finished ..
"endTime": "2020-07-09T22:24:35.1605019+00:00",
"name": "7d3cd0ba-11b3-4180-8298-d9cafc9f22c1",
"startTime": "2020-07-09T22:13:32.0732892+00:00",
"status": "Succeeded"
}
$
The overview page shows graphs for some basic cache statistics - cache throughput, operations per second, and latency.
These charts are part of Azure's built-in monitoring and analytics tools. Additional tools and alerts are available from the pages under the Monitoring heading in the portal sidebar. Learn more in the portal section of the Azure Monitoring documentation.
- Learn more about Azure metrics and statistics tools
- Get help with your Azure HPC Cache