Wednesday, 7 November 2012

Solving Azure Storage latency issues via FNS


 

The Azure Storage access has been plagued with latency issues until MSFT decided to change the network design to FNS.FNS(Flat Network Storage) is a good way to solve the networking issues which arise due to a hierarchical network structure. Azure embracing FNS as Gen 2 storage SKU is a very welcome move. The isolation of compute and storage network is very much required. Having a separate durable network which allows to read , write azure storage at faster speed. This non functional requirement has always been a must required for Azure, the earlier speeds were very slow.

Moreover application plumbing code of managing the latency if the slower reads, write will get some relief.

The patterns are changing and framework codebase are likely to change as well.The scalability numbers of azure storage have to be tested based on the documentation following are the numbers

Within a storage account, all of the objects are grouped into partitions as described here. Therefore, it is important to understand the performance targets of a single partition for our storage abstractions, which are (the below Queue and Table throughputs were achieved using an object size of 1KB):

  • Single Queue– all of the messages in a queue are accessed via a single queue partition. A single queue is targeted to be able to process:
    • Up to 2,000 messages per second
  • Single Table Partition– a table partition are all of the entities in a table with the same partition key value, and usually tables have many partitions. The throughput target for a single table partition is:
    • Up to 2,000 entities per second
    • Note, this is for a single partition, and not a single table. Therefore, a table with good partitioning, can process up to the 20,000 entities/second, which is the overall account target described above.
  • Single Blob– the partition key for blobs is the “container name + blob name”, therefore we can partition blobs down to a single blob per partition to spread out blob access across our servers. The target throughput of a single blob is:
    • Up to 60 Bytes/sec

Some of the definite goods of FNS

  • The flat network design in order to provide very high bandwidth network connectivity for storage clients. This new network design and resulting bandwidth improvements allows us to support Windows Azure Virtual Machines, where we store VM persistent disks as durable network attached blobs in Windows Azure Storage. Additionally, the new network design enables scenarios such as MapReduce and HPC that can require significant bandwidth between compute and storage.
  • Segregation of customer VM based compute from storage from a networking standpoint makes it easier to provide for multi tenancy.

The FNS design does call for a new network design and a software load balancer on the contrary the 10GBps network speed for storage node network solves many of the design challenges at the application level.

The changes to new storage hardware and to a high bandwidth network comprise the significant improvements in our second generation storage (Gen 2), when compared to our first generation (Gen 1) hardware, as outlined below:

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Above are my thoughts The original article can be found here - http://blogs.msdn.com/b/windowsazure/archive/2012/11/02/windows-azure-s-flat-network-storage-and-2012-scalability-targets.aspx

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