The document discusses Windows Azure Drive, which allows mounting cloud storage as a disk volume. It describes uploading files to Azure blob storage by writing them in pages. It also covers how to work with Azure Drive, including mounting, unmounting, and retrying operations using snapshots if an exception occurs. The drive can be mounted in read-only or read-write modes, and files can be accessed directly as if they were on a local disk.

1. Работа с
Windows Azure Drive
25/07/2012
Ревенков Павел
EPAM Cloud Computing Competence Center
pavlo_revenkov@epam.com

2. Data Management Services
• SQL Azure – реляционная база данных;
• Tables – не реляционные таблицы;
• Queue - очереди;
• Blob - двоичные данные;
• Drive - подключаемые облачные NTFS-тома (VHD).
2

3. Пример: CMS-система
Publishers Author
Instance 1 Instance 2 Instance 3 Instance 4
Mount
30 minutes
Snapshot Repository
3

4. Windows Azure Drive
Azure
Subscription
Storage Account
(100 ТВ)
Container
Block Blob (200 GB)
Storage Account
(100 ТВ) Container
Page Blob (1 ТВ)
Storage Account Container
…
(100 ТВ) Azure Drive (1 ТВ)
Storage Account
(100 ТВ)
…
Storage Account
(100 ТВ) 4

5. Загрузка данных в Blob Storage
var storageAccount = CloudStorageAccount.Parse(
ConfigurationManager
.ConnectionStrings[ConnectionStringSetting]
.ConnectionString);
var blobClient = storageAccount.CreateCloudBlobClient();
var container = blobClient.GetContainerReference(containerName);
var pageBlob = container.GetPageBlobReference(blobName);
using (var fileStream = new FileStream(filePath, FileMode.Open)) {
pageBlob.Create(fileStream.Length);
var buffer = new byte[partSize];
while (offset < fileStream.Length) {
var bytesRead = fileStream.Read(buffer, 0, partSize);
pageBlob.WritePages(new MemoryStream(buffer, 0, bytesRead), offset);
offset += bytesRead;
}
}
5

6. 1. public static void UploadVHDFile(string filePath, string containerName, string blobName)
2. {
3. const int partSize = 1024 * 1024;
4.
5. var storageAccount = CloudStorageAccount.Parse(
6. ConfigurationManager.ConnectionStrings[ConnectionStringSetting].ConnectionString);
7.
8. var blobClient = storageAccount.CreateCloudBlobClient();
9. var container = blobClient.GetContainerReference(containerName);
10. container.CreateIfNotExist();
11.
12. var pageBlob = container.GetPageBlobReference(blobName);
13. pageBlob.DeleteIfExists();
14. pageBlob.Properties.ContentType = "binary/octet-stream";
15.
16. using (var fileStream = new FileStream(filePath, FileMode.Open))
17. {
18. int offset = 0;
19.
20. pageBlob.Create(fileStream.Length);
21.
22. var buffer = new byte[partSize];
23. while (offset < fileStream.Length)
24. {
25. var bytesRead = fileStream.Read(buffer, 0, partSize);
26.
27. pageBlob.WritePages(new MemoryStream(buffer, 0, bytesRead), offset);
28.
29. offset += bytesRead;
30.
31. Console.Write('.');
32. }
33. }
34. }
6

7. Режимы работы Azure Drive
CloudDrive
Snapshot
client
URL
Exception
Mount Mount
Да
Author Lease режим Snapshot режим Publisher
чтение
чтение
запись
Windows Azure
Drive
7

8. Работа с Windows Azure Drive
var account = CloudStorageAccount.Parse(
RoleEnvironment.GetConfigurationSettingValue("ConnectionString"));
var drive = account.CreateCloudDrive("drives/vhd");
try
{
drive.Mount(0, DriveMountOptions.None);
...
}
catch (CloudDriveException e)
{
drive = account.CreateCloudDrive(drive.Snapshot().AbsoluteUri);
drive.Mount(0, DriveMountOptions.None);
}
finally
{
drive.Unmount();
}
8

9. 1. public ActionResult Index()
2. {
3. var account = CloudStorageAccount.Parse(
4. RoleEnvironment.GetConfigurationSettingValue("ConnectionString"));
5.
6. var drive = account.CreateCloudDrive("drives/vhd");
7. var letter = string.Empty;
8.
9. FileInfo[] files;
10. try
11. {
12. letter = drive.Mount(0, DriveMountOptions.None);
13. }
14. catch (CloudDriveException e)
15. {
16. drive = account.CreateCloudDrive(drive.Snapshot().AbsoluteUri);
17. letter = drive.Mount(0, DriveMountOptions.None);
18. }
19. finally
20. {
21. files = new DirectoryInfo(drive.LocalPath).GetFiles();
22. drive.Unmount();
23. }
24. ViewBag.Message = String.Format("Azure Drive mounted on: {0}", letter);
25.
26. return View(files);
27. }
9

10. Questions?
10

11. Ссылки и материалы
Differences Between the Storage Emulator and
Windows Azure Storage Services:
http://msdn.microsoft.com/en-us/gg433135
Windows Azure Drive whitepaper:
http://go.microsoft.com/?linkid=9710117
11