Flash and Hybrid block arrays
Flash has changed storage forever and almost every new array purchase needs to have some degree of flash included, so the market now offers three distinct types of array:
As always there is a huge range of price points, due to the architecture, features and performance scaling, for these arrays. Efficiency features are critical in some use cases (i.e. VDI), but less so in many others and performance scaling for the majority of solutions is substantially higher than legacy arrays built just for HDDs.
Historically array performance scaling was limited to the number of HDDs that it could support (i.e. the drives were the bottleneck), with Flash the drives are so fast the bottleneck moves to the controllers. The result of this is that the entry-level arrays will not scale performance beyond 20-30 SSDs so it is very important to have an idea of your ultimate performance scaling requirements.
For most use cases today a hybrid array that has been optimised for flash is the best fit, but there are certainly workloads that need the capabilities of a ground-up all-flash design. As always your requirements and budget will dictate the best fit so let’s take a look at what EMC, HDS and NetApp have to offer:
|EMC VNX||EMC XTREMIO||HDS HUS 100/VM||NETAPP FAS||NETAPP E/EF-SERIES|
|Type||Hybrid/All-Flash Hybrid||Ground-up Design||Hybrid||Hybrid/All-Flash Hybrid||Hybrid/All-Flash Hybrid|
|Largest Flash Drive||800 GB eMLC||800 GB eMLC||400 GB eMLC
1.6 TB FMD (150)/3.2 TB FMD (VM)
|1.6 TB eMLC||1.6 TB eMLC|
|Replacement of drives under maintenance when write limit reached||No||Yes||No (SSD)
|FC, FCoE & iSCSI||Yes||FC and iSCSI||FC and iSCSI (100)
|Yes||FC and iSCSI (E2700)
FC or iSCSI (E5500/EF550)
|Integrated Remote Replication||Yes||No||Yes||Yes||Yes|
|De-duplication||Optional (Post)||Always On (Inline)||No||Optional (Post)||No|
|Compression||Optional (Post)||Always On (Inline)||No (Inline for FMDs)||Optional (Inline or Post)||No|
|Thin Provisioning||Optional||Always On||Optional||Optional||Optional|
|Flash Caching of HDDs||Yes||N/A||No||Yes||Reads (E-Series)
|Auto-Tiering (Up to 3 tiers)||Yes||N/A||Yes||No||No (E-Series)
Read the rest of this post here.