Gaurav Mantri's Personal Blog.

Zone Redundant Storage (Preview v/s Classic)–Compared & Contrasted

Recently I ran into this blog post by Azure Storage Team: Azure Zone Redundant Storage in public preview. When I saw this post, the first thought that came to my mind was “it must surely be a mistake” Smile, after all Zone Redundant Storage (ZRS) has been available for quite some time now.  Out of curiosity, I read more about this and found out that it is actually a lot different than the ZRS that had already been there.

In this post, I will highlight some of the similarities & differences between the new ZRS & old ZRS.

New ZRS is ZRS and old ZRS is ZRS Classic

With this release, storage team has renamed the old of existing ZRS as “ZRS Classic”. The new ZRS for the time being is named as “ZRS Preview” because it is in preview currently.

No Change in Redundancy

From the redundancy perspective, both ZRS Classic and ZRS Preview offer same. You get 3 copies of your data available in a zone. ZRS sits nicely between LRS (Local-Redundant Storage) and GRS (Geo-Redundant Storage).

Redundancy level switching is still not possible

It is still not possible to switch an LRS/GRS/RA-GRS account to ZRS account and vice versa. You will be able to upgrade a ZRS Classic account to ZRS Preview account in the regions where it is available.

ZRS Preview has more services (Files, Queues & Tables)

This is where ZRS Preview starts to differ from ZRS Classic. While ZRS Classic only supported Block Blobs, ZRS Preview has support for not only Blob Service, but also has support for File, Queue and Table Service. Yep, that’s right! Now you can create File Shares, Tables and Queues in a ZRS account.

ZRS Preview has support for storage analytics

This is another big improvement. ZRS Preview has 1st class support for storage analytics which was/is missing in ZRS Classic.

Storage Account Kind

Only for General Purpose v2 accounts, you can specify ZRS Preview redundancy level. For older (read General Purpose v1) accounts, you can only specify ZRS Classic redundancy level.

ZRS Classic marked for retirement

With the announcement of ZRS Preview, Storage team has announced its intent to retire ZRS Classic accounts. Don’t worry, its not going to happen very soon. It will happen somewhere in 2021 so you have good 3 years to move your blobs from ZRS classic account to another account.

ZRS Preview not available in all regions

Because it is in preview, there are limited number of regions where ZRS Preview is available. If you’re using Azure Portal to create storage accounts, you will not be able to create ZRS Classic accounts in those regions. As and when ZRS Preview accounts are made available in other regions, you will lose the ability to create ZRS Classic accounts in those regions using Azure Portal. You will however be able to ZRS Classic accounts in those regions using other means though.

To learn more about the redundancy levels in Azure Storage, please visit this link.

That’s it for this post. I hope you have found this information useful. If you find any issues with the port, please let me know and I will fix it ASAP.

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