TwinStrata

by Greg Roody

Everything about  Computing is a trade off.   The old joke is “Speed, Capacity, or Cost”, you can control 2.

Cloud Computing and Storage are no exception.    How you configure your environment can have a direct impact on your performance levels, but it can also have a direct impact on your budget.

More after the fold….

One of the defining attributes of a Hybrid Cloud Storage model is there is a local storage component which gets used as local cache or buffer.  This helps performance considerably because it is always faster to read or write to disk than to the Cloud.  Simple approaches use one big volume as a buffer (not a cache), and everything goes through it, more or less in the order you intended.  More sophisticated approaches create a real cache, with LRU/MRU policies, read ahead algorithms, and cache coherency checking.

Pure Cloud Storage clients suffer from extreme network latency, and that is usually bad for performance.  If you can afford to wait days to read or write small amounts of data, that model might work for you.  For everyone else, a hybrid configuration is the way to go.

CloudArray, TwinStrata’s breakthrough Cloud SAN software, uses a hybrid storage model with an advanced Intelligent Caching architecture.  We allow you to configure local cache, on a per volume basis if you like, on a sliding scale from a fraction of the target volume size to 100% of the target volume size.

The larger the cache relative to the target volume, the better your local read/write performance will be.  When you get to 100% of the target volume size, reads and writes occur at local disk speed regardless of the latency of your connection to your cloud Storage provider.  Some vendors use a common cache volume for all managed volumes; TwinStrata allows you to use either dedicated or shared cache pools (or both concurrently) for any volume managed by CloudArray.

Remember: Cost, Speed, Capacity:  Pick 2

One of the great things about CloudArray is it is infinitely configurable.  We support local cache disk configurations based on DAS, SAN or NAS volumes.  You can configure those connections through one port (SAN/NAS/RAID controller), or many.  You can use fast disks or slow.  You can use IDE, SCSI, iSCSI, FC, SAS, SSD, or any storage device that can mount using a standard protocol as a device to the CloudArray appliance.

That is also one of the performance configurations when you build out your configuration.  If you attach slow disks to CloudArray, with say a 40 MB/s max throughput over your local storage network, then that is the maximum write performance you will see to CloudArray.  Configure faster drives, connected over a fast network, and you will see a very high level of performance from your CloudArray appliance.  It really comes down to a quality of service decision in the end.

You really need to treat CloudArray like a physical array when configuring both it’s local cache devices and the network links to your application servers.    For applications that require less performance,  backup applications from mirrored copies of your application environment for example, you can use slower/cheaper storage for your local cache.  For those applications which are performance critical – creating remote copies of your Exchange 2010 DAG nodes for example, you want to allocate higher performance storage as your cache devices and use a larger cache device.

By doing this, you can control your costs and your performance levels on a QoS basis across all the applications you want to back up or replicate to Cloud Storage.  TwinStrata is unique in allowing you to configure cache policies and volumes either in groups or individually, and it is the only product which allows a variable caching size to be configured.

We do all of this with Security (256 bit AES encryption) and advanced target data reduction techniques.  You can download a copy and try it yourself, but keep in mind your performance will be related to the performance of the disk and network connection you allocate as cache and your choice of caching policy.

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Tags: Cloud Storage, performance, Storage

This entry was posted on Thursday, August 26th, 2010 at 8:15 am and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.