- What is a SAN?
- How is a SAN different from DAS and NAS?
- What is “Virtualization”? What are its benefits?
- What is iSCSI? What are its benefits?
- What are iSCSI “initiators” and “targets”?
- Which software initiators are available for iSCSI?
- How does iSCSI compare to Fiber Channel?
- What is SATA? What are its benefits?
- What is RAID? What are its benefits?
EzSAN Product Family
- What is an EzSAN SATA RAID Storage Appliance?
- Do EzSAN appliances have limitations on the number of servers connecting to them?
- Can I allocate storage for different servers or applications running on my servers?
- Do EzSAN appliances support block level access?
- Can I use EzSAN appliances for my database?
- Can I use EzSAN appliances to allocate storage for network file systems?
- I have Windows-based file servers, do EzSAN appliances support Windows network file systems?
- Do EzSAN appliances support NFS environments?
- Do EzSAN appliances support Novell network file system environments?
- Can I use EzSAN appliances to allocate storage for my Email servers?
- I have a NAS in my office, can I still use EzSAN appliances?
- Do EzSAN appliances support Linux users too?
- Can I use EzSAN appliances at my headquarters to create storage volumes for people in remote or home offices?
- What differentiates Celeros from its competitors?
- How does Celeros ensure the reliability of its products?
- Are Celeros products covered by a warranty?
A Storage-Area Network (SAN) is a dedicated network that connects all the servers and clients to a shared pool of storage. The pool consists of servers, external storage devices, hubs and switches, and network and storage management tools.
SANs increase the availability of data by letting any server on the network access any storage device on the SAN. Server performance is also increased, as storage-intensive processes such as backup and recovery are off-loaded to the SAN. SANs also lower cost-of-ownership through centralized management.
DAS (or Direct Attached Storage) devices are storage devices that are directly connected to the servers. Servers connect to these devices using high speed interconnects such as SCSI (Small Computer System Interface). The issue with DAS is that the storage utilization is low (on the average 50%) and space cannot be pooled, making management and maintenance difficult.
NAS (or Network Attached Storage) device is a server that is dedicated to file sharing. It allows hard disk storage space to be added to a network without having to bring down these servers and allow the servers and workstations on the network to access this storage at a file level.
There are two issues with NAS that SAN overcomes. First, there are applications such as databases that need a “block level” access to storage as opposed to a file level access, and second that the increased network traffic from servers to storage can cause congestion on local network. SAN allows a block level access to storage and since it has its own dedicated network, server-storage traffic does not impact the local network.
NAS and SAN are complimentary solutions in the sense that NAS servers can use a SAN for their storage. Application servers access files on a NAS server and in turn NAS servers use the block level services on a SAN for their storage.
Virtualization is the combination of multiple network storage devices into what appears to be a single storage unit. Storage virtualization is often used in SANs, and makes tasks such as archiving and backup and recovery easier and faster. Storage virtualization is usually implemented via software applications.
Servers use a high speed interconnect to communicate with their directly attached storage devices called SCSI (Small Computer System Interface). iSCSI (internet SCSI) encapsulates SCSI block storage commands into Ethernet packets for transport over IP networks. This enables servers to communicate with shared storage devices over standard IP infrastructure using standard SCSI storage commands. This allows businesses to easily expand storage capacity and share storage resources across servers. iSCSI has been a proposed standard of IETF (Internet Engineering Task Force) since 2003. Since Ethernet is widely deployed around the world, iSCSI enables businesses to tap the data management and flexibility benefits of networked storage without the high costs and complexity typically associated with traditional Fiber Channel SANs. With iSCSI, companies can cost-effectively deploy data center storage with sophisticated management capabilities for their distributed environments by leveraging their existing networking investments and expertise.
The software drivers that reside on the servers that access the storage servers via iSCSI and encapsulate SCSI commands in IP packets and use the Ethernet to transport them to the storage servers are called “initiators”.
The software taht interprets iSCSI commands on the storage server and allows access to storage under its management is called an iSCSI “target”.
Operating system vendors have endorsed iSCSI enthusiastically and free implementation of iSCSI initiator drivers are available for most. They include:
- Microsoft Windows
- Novell NetWare
- IBM AIX
Fiber Channel, being a high speed serial interconnect, has no routing and failover capabilities and allows for only primitive address management and security considerations. To overcome these limitations, complex configuration schemes have been devised that require specialized expertise and complex environments. These have made Fiber Channel based solutions inherently expensive to acquire and maintain. iSCSI on the other hand utilizes familiar, simple, and low cost technologies such as Internet Protocol and Ethernet and eliminates the need for specialized and relatively expensive expertise.
Advanced Technology Attachment (ATA) is a disk drive implementation that integrates the controller on the disk drive itself. Initial interface to ATA was a parallel interface called Parallel ATA or PATA. Serial ATA or SATA is an evolution of the PATA and is a serial link — a single cable with a minimum of four wires creates a point-to-point connection between devices. Transfer rates for Serial ATA begin at 150MBps. Future rates have been planned for up to 600MBps. One of the main design advantages of Serial ATA is that the thinner serial cables facilitate more efficient airflow inside a form factor and also allow for smaller chassis designs. In contrast, IDE cables used in parallel ATA systems are bulkier than Serial ATA cables and can only extend to 40cm long, while Serial ATA cables can extend up to one meter.
The fundamental principle behind RAID (Redundant Array of Independent/Inexpensive Disks) is that it allows a collection of individual disks to behave as one larger, faster, and more reliable disk. Thus capacity, performance, security, and reliability of the disk subsystems exceed that of its constituents. Once almost exclusively the province of expensive SCSI disks, RAID has gained in popularity with the steady increase in the affordability and performance of ATA drives.
EzSAN have enabled organizations to more effectively share, consolidate, and manage storage resources than was possible with Direct Attached Storage (DAS). The shift from server-centric storage to networked storage has been dependent on the development of technologies that can transfer data to and from storage as fast as, or faster than, direct attached technologies while also overcoming the limitations inherent in parallel SCSI, the dominant interconnect for DAS.
EzSAN SATA RAID Appliance is an iSCSI target networked storage device. Capable of many redundant RAID levels, sets up in minutes and it’s reachable by any IP based network device with iSCSI initiator. EzSAN facilitates the consolidation of your storage needs to help with management and efficient utilization of your consolidated storage. Allocate as big or as little of a volume your need dictates and easily assign it to specific applications or users. For example, EzSAN XR23 w/ 3 Terabyte of storage, could easily allocate one terabyte of storage to your Exchange Email server, allocate another one terabyte to your Oracle database and allocate 50 other 20 gigabyte volumes to 50 different users as remote logical drives.
No, there are no limits to the number of servers connecting to EzSAN. However, it’s always a good idea to consider the bandwidth usage and throughput requirement of the applications and users before assigning a large number of servers to a single EzSAN appliance.
Yes, consider EzSAN as an IP based remote block storage device. You can slice and dice the storage capacity in any way that fits your requirements.
Yes, EzSAN is an IP-based block level device. It’s ideal for databases, file systems, Exchange servers, document management systems, etc…
Yes, you can. Unlike a Network Attached Storage (NAS) that contains a network file system, EzSAN appliances are very well suited for database use. It is a inherently a block level device.
Certainly, many organizations use a variety of network file systems, such as Microsoft CIFS or Sun NFS or Novell to share documents and other network resources. EzSAN appliances fit that model perfectly. As a matter of fact, larger organizations build storage area networks (SAN) to consolidate all of their storage needs to a single location, separate from file, database and web servers. In a sense, each server performs a very specialized function, namely file, database, Web and storage service.
Yes, EzSAN appliances are iSCSI target devices. Any device connecting to EzSAN appliances has to be an iSCSI initiator. Microsoft has an iSCSI initiator software available for download for free.
Once the iSCSI initiator is installed on any server or client machine on the network, that system is capable of using storage volumes that are allocated and assigned specifically to that system.
Yes, EzSAN supports NFS the same way it supports Microsoft network file system or Novell Network file system. iSCSI initiator is required on any NFS servers or NFS client machines connecting to EzSAN appliances.
Yes, EzSAN supports Novell Network file system the same way it supports Microsoft network file system or NFS. iSCSI initiator is required on any Novell servers or Novell client machine connecting to EzSAN appliances.
Yes, EzSAN supports Microsoft’s Exchange Server. Simply download the free iSCSI initiator from the Microsoft web site and install it on your Exchange Server. Allocate appropriate size volumes for each Exchange server and assign them to each Exchange server.
Of Course. Many large organizations use NAS to perform network file system function while they consolidate all of their storage on their Storage Area Network (SAN). EzSAN is the building block for your SAN architecture.
Yes. There are at least two different iSCSI initiators available for Linux.
Yes. Since iSCSI is IP based, the storage could be reachable anywhere connected to IP Network. A central Disk-to-Disk backup is possible for all of your Remote offices.
At Celeros, our mission is to make reliable, high performance storage solutions that are easy to operate and affordable.
While we do not have any religion with respect to the type of technology that can help our customers, we are ardent believers in choosing appropriate technologies that cost effectively solve today’s problems and scale to address tomorrow’s needs.
Our choice of iSCSI storage appliance as the platform of entry into market is dictated by all the advantages that this technology brings to play. It allows us to take advantage of speed, reliability, simplicity, and familiarity of Ethernet and IP to make storage solutions cost effective and scalable.
We pride ourselves with the quality designed into our products and the service and support we provide our customers with.
At Celeros we design our products for rock solid reliability. The components we used are best of breed and carefully selected to have the longest lifetime possible under adverse conditions. Our hard disks are pre selected from the best vendors have to offer. Devices we sell go through a minimum of 72 hours of specialized in-house tests for burn in to ensure that exceptions are identified and changed before customers ever see the product. Our enterprise level devices are designed for no single point of failure.
All Celeros products come standard with a 1 year support and limited warranty on all hardware and software components, including free next business day on-site service. Additional warranty and extended support is available at extra cost from Celeros.