Frequently Asked Questions About XcelaSAN
What is XcelaSAN?
XcelaSAN is an intelligent SAN optimization appliance that provides significant performance improvements for Fibre channel SAN mid-tier storage users, allowing them to reduce TCO by accelerating critical business applications with less hardware. It provides customers with the easiest, most cost-effective way to accelerate application data access on Fibre Channel Storage Area Networks.
How will the XcelaSAN benefit my business operations?
Business operations in mid-range environments will be able to process more on-line transactions in the same time period, or the same number of transactions with significantly improved response time — enabling them to better serve customers, and meet their service level agreements, without having to purchase and install expensive high-end storage systems.
XcelaSAN extends the life of Fibre Channel midrange storage subsystems.
How is XcelaSAN different from other solid state storage?
XcelaSAN dynamically caches high I/O activity data when it is needed – the customer does not need to choose or move high-transaction rate data to the XcelaSAN to experience significant performance benefits. The customer also has the choice to actively tune the XcelaSAN, choosing the LUNS (logical units numbers) that will be cached, and selecting the cache mode of operation for each LUN. Other solid state storage solutions require that the customer identify and move “hot data” from the SAN onto the solid state device. XcelaSAN allows customers to continue using all the features and function of the existing SAN (replication, snapshots, clones, etc.) without moving the data. The dynamic nature of XcelaSAN caching ensures that the current “hot data” is always in solid state.
Why would I put an XcelaSAN in front of a storage system that already has cache in it?
The cache in mid-range storage systems is generally very limited in capacity (less than 32GB). The XcelaSAN can augment the cache in the existing storage systems, and is globally accessible to multiple mid-range storage systems. This means the additional cache will be dynamically allocated where and when required for high I/O activity data.
We cannot tolerate any data loss - how is data protected in the XcelaSAN?
XcelaSAN provides several levels of protection for vital customer data:
XcelaSAN is configured with the same high-quality DRAM modules that are found in mission critical servers with ECC memory error correction and Chipkill technology.
XcelaSAN power supplies and internal backup flash disks are redundant and hotswappable.
XcelaSAN write-through mode ensures that all data on an assigned LUN is written to the attached disk-array's write cache prior to notifying the server that the write is complete. This mode assures both high performance and data protection for mission critical data.
XcelaSAN will de-stage data to internal flash disk in the event of a power failure.
XcelaSAN is configured with redundant UPS systems to support mission-critical application requirements.
XcelaSAN mirroring offers fully redundant data protection for high-availability installations when installed in pairs.
What capacities are available in the XcelaSAN?
XcelaSAN is currently available with 128GB.
What protocols are supported by the XcelaSAN?
XcelaSAN currently supports the Fibre Channel protocol in a storage area network (SAN) environment (or it can be optionally direct attached to servers).
What if my workload isn't cache-friendly?
XcelaSAN is tunable, so cache-unfriendly workloads can simply pass-through.
What is XcelaSAN's throughput?
XcelaSAN delivers 3Gb/s throughput.
What server platforms can connect to the XcelaSAN?
XcelaSAN can connect to any platform that supports Fibre Channel HBA’s.
Which operating systems support XcelaSAN?
XcelaSAN is supported in Unix, Linux, and Windows environments.
What switches connect to the XcelaSAN?
XcelaSAN is interoperable with all major Fibre Channel switches.
Which HBAs (host bus adapters) connect to the XcelaSAN?
XcelaSAN is interoperable with all major Fibre Channel HBAs.
What storage subsystems can be connected to the XcelaSAN?
XcelaSAN supports major mid-range Fibre Channel storage subsystems. Examples include EMC Clariion, HP EVA, SUN 6540/6140, and Compellent StorageCenter.
How many ports does the XcelaSAN have?
XcelaSAN has eight 4Gb/s Fibre Channel ports.
How is XcelaSAN managed?
XcelaSAN has browser-enabled management, monitoring and configuration.
How does the XcelaSAN interact with my operating system?
XcelaSAN is transparent to the operating system.
Is XcelaSAN qualified to work with my SAN?
Dataram certifies that XcelaSAN will operate as documented in any SAN environment in which we install. Dataram Storage Engineers work closely with our customers prior to installation to ensure compatible operation. We take responsibility for owning support, putting customer satisfaction first to avoid any vendor support confusion. Dataram is a member of the Storage Network Industry Association (SNIA) to facilitate standards and co-operation among vendors. In addition, the most common mid-range SANs are installed in our lab for development, testing, certification and quick problem resolution. All of the hardware components in the XcelaSAN are Enterprise Quality Off-the-Shelf-Components (COTS). These components, along with our operating system are qualified with the most common Fibre Switch and SAN manufacturers.
Is the XcelaSAN user-tunable?
Yes, the XcelaSAN has user selectable cache modes that can be assigned on a LUN basis. Available cache modes are write-back, write-through and pass-through.
How long does it take to install an XcelaSAN?
XcelaSAN installation for transparent automatic caching operations takes about an hour. Tuning and selecting LUNs will vary in time depending upon customer requirements.
What are the best applications for the XcelaSAN?
XcelaSAN is ideal for high I/O transaction rate applications like Oracle, SQL, OLTP, Databases, EDA, Exchange and Financial Data Analysis. In these applications, we have seen performance improvement range between 10x to 30x.
Can I install an XcelaSAN if I don't have a Fibre Channel SAN?
XcelaSAN can be directly attached to a server via a Fibre Channel HBA without a SAN.
Is there an evaluation period for the XcelaSAN?
Yes, 30-days.
How does the XcelaSAN function with storage subsystem features like snapshot, replication and de-duplication?
XcelaSAN is transparent to the operation of these features.
We have implemented virtualization of servers and/or storage - how does XcelaSAN function in a virtualized environment?
XcelaSAN is transparent in a virtualized environment.
Where is XcelaSAN manufactured?
XcelaSAN is manufactured in the United States in Dataram’s ISO9001 US manufacturing facility.
Why does the XcelaSAN use volatile DRAM instead of persistent flash storage?
DRAM is the highest performing technology implementation for SAN caching, delivering up to 450,000 IOPS. Persistent flash storage is part of the internal architecture of the XcelaSAN system however, and is used for backup, de-staging upon power loss and to enhance the operation of the system to protect critical data.
My HBAs are 2GB - what will 4GB do for performance?
XcelaSAN will automatically adjust to the lower speed HBAs. When you upgrade your HBAs, the XcelaSAN will perform at the higher rate.
Where are the support documents for XcelaSAN located?
XcelaSAN documents are shipped on a CD and in printed form with the unit.
What is the size and weight of the XcelaSAN?
XcelaSAN is a 2U, rack-mount system, <70 lbs.
What are the power requirements of the XcelaSAN?
XcelaSAN max power = 600 Watt, 120 Volt AC, 2 power cords, NEMA 5-15 plug.
