RenewBlobLease usage increased across all Function Apps since September 30, 2024

[danielelkington]

In the last 2 days (starting September 30, 2024), all 53 of our Function Apps (including both Consumption and App Service Plan apps, Windows and Linux) have suddenly started calling RenewBlobLease on the connected Azure Storage account much more frequently than before. This has caused our Log Analytics usage to increase substantially and is raising cost alerts.

Log Analytics Ingestion:

RenewBlobLease calls:

Investigative information

Previously, each individual function would call RenewBlobLease very consistently, once every 30 seconds.

However in the last two days, during certain hours our function apps have started calling RenewBlobLease several times in each 30 second interval:

Again, this seems to be across all Function Apps. The graph of RenewBlobLease looks the same when filtering by any of our Function Apps.

Repro steps

In a Log Analytics workspace that a storage account linked to a Function App has been logging to, run a query similar to

StorageBlobLogs
| where OperationName == "RenewBlobLease"
| where Uri startswith "https://STORAGE_ACCOUNT.blob.core.windows.net:443/azure-webjobs-hosts/locks/FUNCTION_APP"
| summarize count() by bin (TimeGenerated, 1d)

Observe a spike in logs from September 30:

Expected behavior

RenewBlobLease calls from the Function App should be consistent.

Actual behavior

RenewBlobLease calls from the Function App have been unexpectedly increasing significantly.

[danielelkington]

Adding in data from October 2, it thankfully appears that RenewBlobLease calls have went back to normal. This could have been a 2 day anomaly.

[bhagyshricompany]

Hi @danielelkington got it Thanks for update.if happen again pls update.

[bhagyshricompany]

please try again and see and share the details again .Thanks

[bhagyshricompany]

No update from user Hence closing.if have issue again please raise new request.Thanks