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Introduction

Server-Side Cache

Storage performance in virtualized environments is vital because I/O can negatively impact the system severely since VMs are hungry for IOPS. Opting for a strategy of buying additional hardware storage, including all-RAM storage, to meet the environment's IOPS demands is wasteful and inefficient. However, transforming the way that the existing storage is used seems to be way more prudent.

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Problem

Problems of All-Flash & All-RAM Caching Methods

This multi-tier approach brings up a few issues. Faster and more reliable memory costs more. High-performance or non-volatile memory usage significantly raises the resulting price of the system.

Talking about flash, SLC flash memory is very expensive, while cheaper but still costly MLC flash has shorter lifetime due to up to 10 times lower write/erase cycles limit. VM workload is dominated by random I/O, which is difficult to predict. Insufficient cache memory would mean low cache hit ratio. The idea to get more cache memory stumbles upon high price.

Additionally, certain processes, like starting moved VMs on destination node after vMotion, Live Migration or XenMotion, cause drops in performance because the VMs are started in a “cold state”. This means that the VM is started without its data in cache, causing a dramatic loss of performance.

Using conventional RAM instead of non-volatile memory, renders the cache prone to errors, because data in cache will be lost in case of hardware malfunction or power outage. On the other hand, utilizing power-independent memory raises the problem of high price, referenced above.

Traditional Cache Solution

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Solution

Server-Side Cache Solution

Price of the system is lower, because StarWind uses commodity hardware like conventional RAM, SATA SSD, MLC FLASH or so for caching. Expensive flash memory will have better lifetime because of possible SSD usage in either write-through or write-back mode, while StarWind uses conventional RAM as a write buffer and Level 1 cache to adsorb writes. This approach turns Flash into Level 2 cache, reducing the amount of write cycles going through it, prolonging its life. Additionally, space reduction technologies, namely in-line deduplication and compression, lower the actual amount of data to be written, allowing flash memory to last even longer, cutting the bills by requiring rare replacements.

StarWind raises performance by having bigger cache for the same money. Commodity inexpensive hardware is used – MLC flash instead of costly SLC flash, so more memory may be bought to meet workload requirements. In addition, starting VM’s after migration does not affect the performance as all moved VMs are started in “hot state” because caches are kept coherent – synchronized between nodes. This means that the destination node holds the required data in cache, so the VM starts without loss in performance.

Reliability is kept at maximum – StarWind basically mirrors data in cache between multiple nodes, creating distributed cache. This way, even when the power goes out, all data is safe, because redundant replicas are stored on all nodes. Besides, cache blocks are digitally signed, negating the possibility of silent data corruption – bit rot. Additionally, space reduction technologies lengthen the life of flash memory, lowering the risk of failure.

StarWind Cache Solution

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Conclusion

Get Maximum Performance and Reliability with StarWind Server-Side Cache Solution

StarWind uses commodity inexpensive – DRAM, SATA, MLC and high-performance – PCIe, DIMM Flash hardware providing maximum possible performance and reliability without breaking the bank.

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What The World Says About Us

StarWind gets praise for its solution's high level of customization in the 2019 Magic Quadrant for HCI



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Success Stories

We were able to build 2-node storage clusters based on virtualization in 19 hypermarkets without any problems and with high cost-efficiency.

Vass Sandor, IT Infrastructure Leader

By being able to virtualize our environment with StarWind, we were able to retire some old hardware, get our services highly available, reduce power consumption and heat in our server closet.

David Gardner, Information Systems Manager

We are satisfied with StarWind. The support is really fantastic. Whenever any issue arises, the response is very prompt, and solution is immediate.

Srinivas Kouda, Company’s Representative

StarWind got us off the clustered environment, which was a big help. So, I could regain control of my storage and reclaim and redistribute the space we desperately needed.

Ryan Fulton, Company’s Representative

Price + Simplicity. StarWind VSAN offers great pricing and allows us to get work done without expensive custom hardware. It also makes getting back online quick and easy after an outage or hardware failure.

Aaron Hayes, IT Manager

We chose StarWind Mainly because of the cost compared to other vendors. Simplicity of setup was also a major factor and I like the fact that you don’t need a vendor certified engineer to perform the installation.

John Harris, Windows System Administrator,
Department of Physics, University of Oxford

Because of recommendations of older colleagues, with StarWind, we got a reliable storage with no additional hardware. There was a need to increase IT infrastructure performance and we saw StarWind as the most cost-effective solution.

Željko Medić, Director of IT Department

StarWind is the best storage product I have ever used! It satisfies and exceeds requirements.

Joe Gursky, Director of IT
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