question

MattiaFravezzi-5681 avatar image
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MattiaFravezzi-5681 asked MattiaFravezzi-5681 answered

Sometimes download from azure blob storage is very slow


When download file from blob storage sometimes it can take more than 10 minutes. What's can be the problem?

STORAGE:
Performance:Premium
Replication:Locally-redundant storage (LRS)
Account kind:BlockBlobStorage
Location:Switzerland North

FILES:
from 4mb to 60mb

CLIENT:
cordova application using "@azure/storage-blob": "12.9.0",
from Italy
connection check: done is always good (>100mb/s)


CODE:
const containerClient = await this.blobServiceClient.getContainerClient(containerParentName);
let blobs = await containerClient.listBlobsByHierarchy("/", { prefix: containerName + "/" });
for await (const blob of blobs) {
const blobClient = await containerClient.getBlobClient(blob.name);
const blobProp = await blobClient.getProperties();
const downloadBlockBlobResponse = await blobClient.download(null, null, {
onProgress: (ev) => {
........
}


METRICS :
E2E Latency very high
Server Latency normal

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azure-blob-storage
· 1
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Hello @MattiaFravezzi-5681

Just checking in to see if the information provided was helpful.

If the reply helped you, please remember to accept as answer.

If not, please reply and tell us the current situation in order to provide further help.

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LuisRodriguez-MSFT avatar image
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LuisRodriguez-MSFT answered

Hello @MattiaFravezzi-5681

Welcome to Microsoft Q&A Platform.

End-to-end (E2E) latency measures the interval from when Azure Storage receives the first packet of the request until Azure Storage receives a client acknowledgment on the last packet of the response.

There are many different factors that can be related, like operation size, client configuration, client CPU/memory or network path:
https://docs.microsoft.com/en-us/azure/storage/blobs/storage-blobs-latency#factors-influencing-latency

I would recommend checking the article below as starting point:
https://docs.microsoft.com/en-us/azure/storage/common/troubleshoot-latency-storage-analytics-logs

A network capture taken at the time of the issue should help, you can look for retransmits and high response times
If the issue requires remote assistance & collection of logs for further assistance, I request you file a support ticket if you have a support plan

I hope this helps!


Please don’t forget to "Accept the answer" and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

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MattiaFravezzi-5681 answered

I followed all points in those link, but I didn't solve my problem.
I solved problem adding CDN at Azure storage and connecting there from my mobile application.

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