Free Support Guide How to Choose a Server Once a network has grown beyond 5 users a workgroup environment becomes unreliable for transferring information and accessing resources over the network. At 10 users you can expect to see several computers crashing a week (unexpected errors). The risk to your hard earned data increases. When this happens, typical problems are file corruption, and worst still the operating system corrupts even the newer operating system have these problems. Also newer Operating Systems have connection count limit built in, often resulting in unexplained file Access Denied errors. At this point you need a server. This server may still be used in a workgroup environment. A server being used in a workgroup is often referred to as a Workgroup Master. This machine will eliminate your connection limit issues providing you have enough user licenses to access the machine and you have moved the shared resource to this machine. You will also benefit from the fact that this type of machine is left on so it resources are available to all the users. This will allow users to turn their own machines off and perform updates as and when needed without affecting other users. You can also if careful make sure this machine is the network “MASTER BROWSER” thus preventing forced election of all the computers on the network. By using the server as a domain master you will gain many more benefits, centralised security being the most important. On a network these systems are responsible for providing secure access to network resources. A typical Microsoft windows server will provide the following services. DHCP – Assigns IP Addresses to requesting devices. DNS – Provide name services to all network equipment ADS – Active Directory Services for requesting Microsoft Windows Users and Services Common authentication to server services Whichever mode you choose to run these machines in the following statements about the hardware will apply and you should consider all points when making your choice. These machines are designed to be more reliable than the average desktop machine: They work a lot harder They are rarely turned off The drives are normally in constant use They are often under constant attack from remote communication sources Their designed operational life tends to be longer than that of a desktop computer There are 3 parts to the decision process when choosing a server. Network Resource Planning Server Hardware choices Server Software Choices Guide Reference: FSG-0002-01 Page 1 of 14 How to Choose a Server Network Resource Planning In this section we use a few technical terms which are explained more fully under the Server Hardware Choices section. This comes down to how many users, what resources are being provided, and how many branch offices (remote sites) or remote users need access. Consideration should be given to branch offices having their own network and local server this helps security by keeping local resources local to the users as well as preventing un-necessary network traffic across the data communication link (Often the internet). (If you are running an application service for large number of external/home workers you may need to increase the power of the server and even consider some fault tolerant technology. As the number of users grows you should add more servers to the network. Use the following as a guide for the number of servers at each site: Number of Users Up to 30 Users Up to 60 Users 60 Users and Over Server Server 1 Server 1 Server 2 Server 1 Server 2 Server 3 Function Primary Master Primary Master Secondary Master Primary Master Secondary Master Secondary Master Services DHCP, DNS, ADS, GC DHCP, DNS, (ADS), (GC) (DHCP), (DNS), ADS, GC DHCP, GC, (ADS) (DHCP), DNS, (GC) ADS, (DHCP) The above services are the basic network provision services for a Microsoft Server based solution a Linux/Unix solution will have equivalent based services. The services in parenthesises are backup services which should provide a degree of fault tolerance. Also many IT professionals have different ideas about the splitting of these services and often your operating environment may determine how these services are distributed. What we are trying to show is that the services are distributed evenly amongst the servers. Once your user count goes beyond 90 users performance improvement is not necessarily achieved by adding extra servers. To achieve better performance it may be better to provide higher performance servers. This is because services generally can’t be split across 2 or more servers unless you are using a clustering technology. Also if you operate your own email server and have branch offices with more than 10 users you would benefit from an additional mail server at these sites. With a more recent development of Off-Premise server services your choice widens. You could reduce the number of servers you require by out sourcing some of your server based services. Read our Free Support Guide FSG-0001-01 for more information. One of the prime functions of a server is to provide file storage either for an application or directly for users. Choosing the right storage strategy is very important. So here will provide some guidance on storage capacity, and in the Server Hardware Choices section you will find information on the type of storage systems & devices. Storage Capacity Requirements The storage capacity you need depends on several factors; the applications you use; number of users; the amount of document processed and stored; expected business growth; historical archive period. Always over estimate the figure and always round up. Remember your server is expected to last 5 years data growth. Page 2 of 14 Guide Reference: FSG-0002-01 How to Choose a Server The figures given below are for guidance and you need to make your own assessment to gain an accurate storage capacity figure for the business. Getting the storage strategy wrong or the storage capacity figure wrong could involve a serious amount of down time getting the storage strategy technology right will mean very little down time. Storage Capacity Guidance Table for 5 years. User Type Activity Light Commercial User Email Documents Document Scans (Pages) Medium Commercial User Email Documents Presentations Document Scans (Pages) Heavy Commercial User Email Documents Presentations Databases Document Scans (Pages) Document Clerk Email Document Scans (Pages) Application User (No Email) Application Application User with Email Email Application File Count Per Week 25/50 25 5 Totals: 50/100 50 0.5 25 Totals: 100/200 50 1 0.25 50 Totals: 100/100 500 Totals: n/a Totals: 100/100 n/a Totals: Capacity Required 6 Months 1 Year 60MB 120MB 1MB 2MB 65MB 130MB 126MB 252MB 120MB 240MB 2MB 4MB 130MB 260MB 325MB 650MB 577MB 1.154GB 240MB 480MB 2MB 4MB 260MB 520MB 325MB 650MB 650MB 1.3GB 1.477GB 2.254GB 156MB 312MB 6.5GB 13GB 6.656GB 13.32GB 50MB 100MB 50MB 100MB 156MB 312MB 50MB 100MB 206MB 412MB 2 Years 240MB 4MB 260MB 504MB 480MB 8MB 520MB 1.3GB 2.308GB 960MB 8MB 1.04GB 520MB 2.6GB 5.908GB 624MB 26GB 26.63GB 200MB 200MB 624MB 200MB 824MB 3 Years 360MB 6MB 390MB 756MB 720MB 12MB 780MB 1.95GB 3.462GB 1.44GB 12MB 1.56GB 780MB 3.9GB 8.862GB 936MB 39GB 39.94GB 300MB 300MB 936MB 300MB 1.236GB No Archive 600MB 10MB 650MB 1.26GB 1.2GB 20MB 1.3GB 3.25GB 5.77GB 2.4GB 20MB 2.6GB 1.3GB 6.5GB 14.77GB 1.56GB 65GB 66.56GB 500MB 500MB 1.56GB 500MB 2.06GB For other Professional Users add the following to a Medium Commercial User to arrive at their Storage capacity. CAD/CAM User CAD/CAM Drawings 5 650MB 1.3GB 2.6GB 3.9GB 6.5GB Web Designer Web Pages 100 130MB 260MB 520MB 780MB 1.3GB Graphic Designer Graphic Design 10 2.6GB 5.2GB 10.4GB 15.6GB 26GB Photographer Photos (Hi-Res) 10MB 250 65GB 130GB 260GB 390GB 650GB Photographer Photos (Med-Res) 5MB 250 32.5GB 65GB 130GB 195GB 325GB Photographer Photos (Lo-Res) 1MB 250 6.5GB 13GB 26GB 39GB 65GB Photographer Photos (Web) 100KB 250 650MB 1.3GB 2.6GB 3.9GB 6.5GB Please note that this is a guide most businesses will have differing requirements. In addition to the above every server will require additional storage space for the operating system, security application, applications they serve to users and a cache storage area normally 2-3 times the RAM size of the server. From the above table a couple of things become very clear, email, scanned documents and graphics consume storage capacity. Without an archive strategy the numbers become very large indeed. Guide Reference: FSG-0002-01 Page 3 of 14 How to Choose a Server How to use the guide Make a list of all your user types and the number of users of that type. Do this for all your sites. Remember to add your remote users to the list. (Only relevant for Email and Application Services) Add up all the users add to this the expected number of users you think you may have in 5 years time. This will tell you how many servers you need to operate the basic services. You may need to add an extra server for an application you may be running. Write a list of these servers down. Any Off-Premise server service you subscribe to you can omit the server and its storage requirements. Next decide how much archive history to keep on the server. You could even keep a different archive history for emails from the main file storage. You could keep 1 year email history and 5 years of files. On your list of user types write down the total storage capacity for that user type required minus the email capacity (use the figure that is in the same archive history column you have chosen for the main file storage) and multiplied this by the number of user of that type. Do this for all your user types but ignore the application user types. On your list of user types write down the email storage capacity for that user type for your desired archive history option. Do this for all the user types. If you have application user types (you should have one for each application type) use the total number users multiplied by the storage required. Better still is to a figure given to you by the application vendor this may be a size per user or size based on the number of records. Use the most appropriate figure and remember you have to think about what the size will be in 5 years time. Also don’t forget to add the application installation requirements too. Alternatively divide the number of records you have with the file size (or directory size of the application data) this will give you a record size multiply this by the number of records you hope to have in the application after 5 years add 20% to the figure for a safety margin. Now total all the mail file storage and email storage capacities from the user types. Hopefully now you should have a total storage requirement for main file storage, emails, and each application. Now for each server add 30Gbytes plus 3 times the RAM capacity and 50MB multiplied by the number of total network access users. Example: This company has 22 Staff at 2 sites and also has 3 remote staff. They want to have their own internal email server, accounts system and CRM system. The 3 remote users connect to site 1. This company has no archive policy for File usage and a 2 year archive policy for emails. First thing is to identify the types of staff. 4 staff are Light Commercial Users 4 staff are Medium Commercial Users 2 staff are Heavy Commercial Users 10 staff are Application with email users 2 staff are Graphic Designers 3 staff are CAD/CAM Users Page 4 of 14 Guide Reference: FSG-0002-01 How to Choose a Server The next step is to work out the number of users for each application. This is an important step so you know the number of access licenses required for applications. 25 Network Access Users (Total number of staff) 8 Accounts System Users 9 Users on our CRM System (3 are Remote Users) 25 Users using Email Next draw up a list of users and the application user count at each site and add the remote users to the site they connect to. Site 1: 12 Staff are based at this site 1 Heavy Commercial User 2 Medium Commercial Users 3 Light Commercial Users 6 Application with email users (3 Users are Remote) 1 Graphic Designer 2 CAD/CAM Users Number of users for each application 15 Network Access Users (3 are Remote) 6 Users use Accounts System 6 Users use the CRM System (3 are Remote) 15 Users using Email (3 are Remote) Site 2: This site has 10 Staff 1 Heavy Commercial User 2 Medium Commercial Users 1 Light Commercial Users 4 Application with email Users 1 Graphic Designer 1 CAD/CAM Users Number of users for each application 10 Network Access Staff 3 Users use Accounts System 3 Users use the CRM System Now we have the users count and types and the split between the locations we can put together a server count and a storage capacity estimate. If there was a high speed dedicated communication link between the 2 sites we could use 4 servers but we will assume there is not a dedicated high speed communication link. Guide Reference: FSG-0002-01 Page 5 of 14 How to Choose a Server As the user count is over 5 at each site it would be better to use 2 servers one at each site. In addition we have over 10 users at each site using email so we would require 2 mail servers to handle the email. Also 2 additional servers would be required to handle the 2 main applications. For an On-Premise solution we would require 6 servers, 4 at site 1 and 2 at site 2. At the end of this example we will give you an alternative solution using a Hybrid solution using On-Premise and Off-Premise services. Now we need calculate the storage capacity required. Site 1: 1 Heavy Commercial User 2 Medium Commercial Users 3 Light Commercial Users 6 Application with email users 1 Graphic Designer 2 CAD/CAM Users User Count User Type 1 2 3 6 1 2 Heavy Commercial User Medium Commercial Users Light Commercial Users Application Users with email Graphic Designer User CAD/CAM User Main File Storage 12.37GB 9.12GB 1.98GB 30.57GB 22.14GB Totals: 76.18GB Email Storage 4.136GB 960MB 720MB 3.744GB 480MB 960MB 11GB Site 2: 1 Heavy Commercial User 2 Medium Commercial Users 1 Light Commercial Users 4 Application with email users 1 Graphic Designer 1 CAD/CAM Users User Count User Type 1 2 1 4 1 1 Heavy Commercial User Medium Commercial Users Light Commercial Users Application Users with email Graphic Designer User CAD/CAM User Main File Storage 12.37GB 9.12GB 660MB 30.57GB 11.07GB Totals: 63.79GB Email Storage 4.136GB 960MB 240MB 2.496GB 480MB 480MB 8.792GB Now we have the storage requirements for the user’s files and emails. The email application program requires 10GBytes of installation and operating space The accounts application vendor told this company that 100Mbytes of storage per user per year was more than adequate for the expected accounting usage. Page 6 of 14 Guide Reference: FSG-0002-01 How to Choose a Server As there are 8 Accounting users 4GBytes of data storage is required. The application requires a further 1.5Gbytes on installation space. The companies CRM System is based on a SQL database they have 1,000 records stored taking 160Mbytes of space they think they going grow their CRM records to 13,000 over the next 5 Years. 1,000 Records / 160Mbytes = 160Kbytes per Record 13,000 Records x 160Kbytes = 2.08GBytes of storage required over 5 years The CRM application needs only 35Mbytes of installation space. Now we calculate what each server requires. For this example all the servers have 16GBytes of RAM the RAM requirements for a server are discussed later in the section about server hardware. Server Site 1 - Primary Master Requirement Operating System 25 Users x 50Mbytes Main File Storage Cache RAM 16Gbytes * 2 Site 1 – Email Server Operating System 25 Users x 50Mbytes Email Storage Email Application Space Cache RAM 16Gbytes * 2 Site 1 – Accounts Application Server Operating System 25 Users x 50Mbytes Application Data Storage Application Space Cache RAM 16Gbytes * 2 Site 1 – CRM Application Server Operating System 25 Users x 50Mbytes Application Data Storage Application Space Cache RAM 16Gbytes * 2 Site 2 - Primary Master Operating System 25 Users x 50Mbytes Main File Storage Cache RAM 16Gbytes * 2 Site 2 – Email Server Operating System 25 Users x 50Mbytes Email Storage Email Application Space Cache RAM 16Gbytes * 2 Total: Total: Total: Total: Total: Total: Guide Reference: FSG-0002-01 Capacity 30GBytes 1.25Gbytes 76.18GBytes 32GBytes 139.43GBytes 30GBytes 1.25Gbytes 11GBytes+ (8.792GBytes) 10GBytes 32GBytes 93.042GBytes 30GBytes 1.25Gbytes 4GBytes 1.5GBytes 32GBytes 68.75GBytes 30GBytes 1.25Gbytes 2.08GBytes 35MBytes 32GBytes 65.365GBytes 30GBytes 1.25GBytes 63.79GBytes 32GBytes 127.04GBytes 30GBytes 1.25Gbytes 8.792GBytes + (11GBytes) 10GBytes 32GBytes 93.042GBytes Page 7 of 14 How to Choose a Server Operating a single domain will require the total user count requirement for network access services and with 2 email servers using the total email storage figure. Alternative Hybrid Solutions All the following 7 solutions are valid and will work but they don’t fulfil the company’s requirements. The company wanted keep the applications On-Premise. All the following options have a cloud based element. Hybrid Solution 1 Server Solution Site 1 - Primary Master Off-Premise Email Service for 25 Users Off-Premise Accounts Application Service 8 Users Off-Premise CRM Service for 7 Users Site 2 - Primary Master Solution requires 2 Servers and 3 Off-Premise Services Capacity 139.43GBytes n/a n/a n/a 127.04GBytes Hybrid Solution 2 Server Solution Site 1 - Primary Master Off-Premise Email Service for 25 Users Site 1 - Accounts Application Server Off-Premise CRM Service for 7 Users Site 2 - Primary Master Solution requires 3 Servers and 2 Off-Premise Services Capacity 139.43GBytes n/a 68.75GBytes n/a 127.04GBytes Hybrid Solution 3 Server Solution Site 1 - Primary Master Off-Premise Email Service for 25 Users Off-Premise Accounts Application Service 8 Users Site 1 - CRM Application Server Site 2 - Primary Master Solution requires 3 Servers and 2 Off-Premise Services Capacity 139.43GBytes n/a n/a 65.365GBytes 127.04GBytes Hybrid Solution 4 Server Solution Site 1 - Primary Master Site 1 - Email Server Off-Premise Accounts Application Service 8 Users Off-Premise CRM Service for 7 Users Site 2 - Primary Master Site 2 - Email Server Solution requires 4 Servers and 2 Off-Premise Services Page 8 of 14 Capacity 139.43GBytes 93.042GBytes n/a n/a 127.04GBytes 93.042GBytes Guide Reference: FSG-0002-01 How to Choose a Server Hybrid Solution 5 Server Solution Site 1 - Primary Master Off-Premise Email Service for 25 Users Site 1 - Accounts Application Server Site 1 - CRM Application Server Site 2 - Primary Master Solution requires 4 Servers and 1 Off-Premise Services Capacity 139.43GBytes n/a 68.75GBytes 65.365GBytes 127.04GBytes Hybrid Solution 6 Server Solution Site 1 - Primary Master Site 1 - Email Server Site 1 - Accounts Application Server Off-Premise CRM Service for 7 Users Site 2 - Primary Master Site 2 - Email Server Solution requires 5 Servers and 1 Off-Premise Services Capacity 139.43GBytes 93.042GBytes 68.75GBytes n/a 127.04GBytes 93.042GBytes Hybrid Solution 7 Server Solution Site 1 - Primary Master Site 1 - Email Server Off-Premise Accounts Application Service 8 Users Site 1 - CRM Application Server Site 2 - Primary Master Site 2 - Email Server Solution requires 5 Servers and 1 Off-Premise Services Capacity 139.43GBytes 93.042GBytes n/a 65.365GBytes 127.04GBytes 93.042GBytes Main file storage capacity is generally stored on the Primary Master server but can be stored on any of the servers. It is also possible to store these files separately on dedicated storage devices that attach to the network such as a Storage Area Network (SAN) or a Network Attached Storage (NAS). These technologies are discussed in a separate document. When you use such technologies you can subtract the Main File Storage, Email Storage or Application Storage capacity from the server requirement and add the appropriate figure your storage capacity requirement to your dedicated storage device. Backup Planning Once you have compiled this information for your network you can also derive the amount of capacity required for your backup system. To this add the capacities of all the servers used & dedicated storage devices located at each site, this will give you the backup capacity required for each site. The backup device generally is attached to only one of the servers at each site. Using the above example the backup capacity requirement for each site would be: Site Backup Capacity Site 1 Site 2 367GBytes 221GBytes Guide Reference: FSG-0002-01 Page 9 of 14 How to Choose a Server Various backup strategies can be adopted for the needs of this company. The backup may be split into smaller chunks but your backup device capacity should be greater than the largest Logical storage device you have at the site. Other considerations about network resource planning You should have an Uninterruptable Power Supply (UPS) of the adequate power rating for every PSU Mains connection on the server with the most mains connections. One UPS may serve more than one server but not 2 PSU’s on a single server. This will prevent corruption of files and the operating system if power is suddenly lost. When considering the cost remember the most expensive item on your network is the user. If they can’t work when a server is down it is still costing you their wages. Hardware Server Choices Now you have planned the network infra structure you can make a more informed choice on the hardware technologies deployed in a server system. Servers are in their basic form the same as desktop computers they will function the same way. You could use a desktop computer with a server operating system. So why are server products different? Server main boards are built to last longer Most servers have a dual redundant power supply Server RAM memory normally has Error Correcting Code (ECC) Interface Cards should be Active rather than Passive (Have on-board CPU’s) Main boards Server main boards are designed to be more reliable. In general they support multiple CPU’s, use ECC Reg. Memory and have other feature. They support 64Bit Cards which allow data to move faster to peripherals and storage devices. For this reason High Performance workstations sometimes use server main boards and the technologies discussed below. Redundant Power Supply This means that there are extra power supply units which are active in case one fails. This will allow the server to continue operating. When using Redundant Power Supplies it is important make sure that if a unit fails the remaining power supply(ies) are able to provide the required power rating. If this is not done when a PSU fails it will cause a chain failure to occur on all the remaining units due to excessive power draw. There is a double benefit to Redundant Power Supplies in normal operation all the PSU’s will share required power load between them making them less stressed thus more likely not to fail as well as the fact that you system should continue to operate if you have a failure of a single unit. ECC Reg. Memory This means that every byte of information is stored with an error correction bit so when an error is detected it can be corrected. The register means that the memory will hold the data so that it is available through the processor instruction cycle this improves the speed at which the CPU can obtain the stored data from the RAM and make it more reliable. Although memory access errors are rare something in the order of 1.0E 18, they will nearly always cause the server to crash. Storage Devices SAS/SCSI v SATA/IDE Hard Disk Drives A SAS (Serial Attached SCSI (Small Computer System Interface))/SCSI based server will offer better performance and more reliable than SATA (Serial Advance Technology Attachment)/IDE (Integrated Drive Electronics) storage devices. Page 10 of 14 Guide Reference: FSG-0002-01 How to Choose a Server SATA/IDE drives should only be used on the Low End Servers as an economic option. SAS/SCSI disk drives are by far the best devices they are reliable and very fast. In general most servers use a SAS/SCSI chassis which facilitates hot swapping features to allow a failed drive to be replaced while the server is up and running you can only do this if you are using a relevant RAID configuration. The most important factor for any type of Hard Disk Drive (HDD) is its spin speed. This determines how fast data can be pulled from the magnetic stored information on the platter to the controller. The next important factor for speed is the head time given as track-to-track and head settling time. SATA/IDE drives 7,200rpm is better than 5400rpm SAS/SCSI 15,000rpm is better than 10,000rpm RAID Technology RAID stands for Redundant Array of Inexpensive Disks. We will ignore the inexpensive part because server disk drives are normally more expensive than desktop drives for the reasons stated. But when this term was coined drives in use where either desktop hard drives or mainframe hard drives. What is of our concern is the fact that a group of disk drives are available to controller. This controller is more intelligent than a standard disk drive interface and will treat these separate drives as part of a storage unit depending on the configuration that it has been given. RAID controllers are very intelligent interfaces. RAID configurations are defined by a number and are referred to universally across the industry. There are 3 configurations of interest: RAID0 All the Drives are used to create a single volume this improves access speed as there are more drive heads to access the data stored on the volume. There is no security of data in this configuration. RAID1 2 drives are used; one is used as an exact match to the other this configuration is often referred to as a Mirror Array. This configuration is slower to write data as it has to write the data twice, but is the most secure as one drive can fail and the server will still continue to operate normally. RAID5 3 or more drives are used to create a volume with 3 drives, 2 drives make the volume while the 3 rd is a parity drive. This configuration is a compromise between speed and security. If a drive fails the server will have to be taken offline to repair the array but should continue to work, it will access data faster than RAID1 as there is more heads across the volume but will write slower as the parity drive requires calculating as well as writing. There are other RAID configurations that are not commonly used and there are few adopted configurations that are. RAID 1+0/RAID 0+1/RAID10 - RAID0 then mirrored RAID1 RAID 5+0/RAID 0+5/RAID50 - RAID0 made of RAID5’s RAID 5+1/RAID 1+5/RAID51 - RAID5 then mirrored RAID1 HOT SPARE This is a name given to a drive that is in the array and is available to take over and be used if a drive should fail in an array. Most intelligent RAID controllers will do this automatically. Guide Reference: FSG-0002-01 Page 11 of 14 How to Choose a Server Do not think that a RAID is a replacement for backing up they are intended as a means to keep the server up and running or providing larger storage capacities. If your server is destroyed by Fire, Flood, Explosion etc, it will result in the loss of all your data. Given the cost of drives you should always operate with one of the RAID configurations and preferably with a HOT SPARE available for each array. You should purchase a drive chassis is it will allow for swapping of disk drives when a drive fails. High Performance Standard Servers come with 1-2 Processors and embedded RAID controller they are designed as a complete solution for a smaller company often including a backup drive. High Performance Servers offers many additional features and a greater range of options. 2 or more processors with many cores SAS/SCSI RAID controller Significant RAM expansion capability Drive Chassis Virtualisation Virtualisation is when you run separate instance of the operating system on the same hardware platform. This means that you could have 4 servers appearing on the network but in fact there is only one physical server system. Most new main boards support the capability of virtualisation. When you virtualise a system the operating system that manages the virtual machines is called the Host and the virtual machines it is running are referred to as the Guests. Fault Tolerance Technology When the term Fault Tolerant Technology is used it means there is duplication in the hardware that can take over if a fault occurs normally without causing any disruption in service. The 2 most common of these technologies we have discussed earlier is the Redundant Power Supply and some RAID configurations (RAID1, RAID5). These 2 fault tolerant technologies cover the most stressed components in a computer system. Another fault tolerant technology found in some high performance rack servers is a group of hot swappable fans. To make a server fully fault tolerant is extremely costly as special network core switching technology is required. Clustering technology becomes a better alternative when you need to achieve this. Clustering Technology Clustering technology is when multiple servers are linked together to provide what will appear as a single server. This sounds easy but in practice requires specialist hardware and software. This technology is used when you have100’s or even 1000’s of users. Internet hosting companies and Internet service providers use this type of technology extensively. The additional benefit of this technology is that it is fully fault tolerant when implemented correctly. A server machine may fail totally and the services it provides will continue to be available as they were shared amongst several servers. In reality all that happens that the work load is such spread across fewer servers. Hardware vendors introduced the term blade servers. These are bare bone server boards in compact form that slide into to a rack that provides a common bus for these servers to talk to each other and the peripherals that connect to this server. This makes a cluster server more cost effective and saves a space and power. Page 12 of 14 Guide Reference: FSG-0002-01 How to Choose a Server Server Software Choices The Network Operating System (NOS) is just as important as the server hardware. There are 2 main operating system types UNIX/LINUX & Microsoft Windows, the only exception to these are generally vertically market application servers that serve the application to users via terminal or user computer using a thin client application. UNIX/LINUX Mainly used by larger companies with custom written applications or Internet Service Providers/Hosting. Although the software costs are very low the support required to maintain these systems is significant (Not problem to companies that employ lots of technical staff with the required skills. Microsoft Windows Tends to be used commercially integrates well to client systems. It also offers a familiar interface for doing tasks on a server so the support level required is much lower. Microsoft offers many versions of its server products and each version has its own set of restrictions. For smaller companies Microsoft offer server products with fixed number of user access licenses (Commonly referred to as CALs) once you reach this limit you have to upgrade your server operating system to the next level. Microsoft Licenses are based on the number of processors or the virtualisation environment needed these Licenses require CAL licenses for each user. In both cases additional Server Service Application like email or SQL will require their own CAL Licenses for the number of users using the particular service. In the late 1990’s Microsoft introduced a product for small businesses to use. This product was designed to run on a single server and was limited to the number of users that could be connected. This product offered great value to small businesses particularly as the price of hardware began to fall in the early 2000’s. The key attraction of this product was Microsoft Exchange Server was included which meant the 2 most important components of an IT strategy where bundled together. Microsoft in 2012 announced there will be no inclusion of the Microsoft Exchange Server in this product. ‘Microsoft Windows Small Business Server 2011’ being the last release with the email server product and to make matters worse this product was based on ‘Microsoft Windows Server 2008 R2’ which means the support cycle is reaching the end. This product was an extremely popular choice for companies that wanted on-premise server technologies. The absence of this product will make the choice for many small businesses even harder. Microsoft’s reasoning is that no one is buying licenses for product they don’t wish to use as a company may wish to use a cloud based service for their email. It would also be fair to say with recent explosion in email usage user’s mailboxes have grown significantly and having a mail server and a primary domain master service on a single server does not perform well. In the above example you could operate using Essential Business Server 2012 but there is no expansion capability for new users. It would be more prudent to opt for Standard Server 2012 which will allow for more than 25 Users, You will also get the benefit of being able to isolate the main function of the server into their own virtual server. This will make support and migration as you grow easier. There is an alternative to solution to our example and that is to virtualise all the servers into a physical hardware platform. This solution would require: Guide Reference: FSG-0002-01 Page 13 of 14 How to Choose a Server 2 High Performance servers one at each site 1 Data Centre Server 2012 License for Site 1 1 Standard Server 2012 License at Site 2 Be aware that the storage requirements change as does the operating amount of memory. Summing Up In general when deciding on your server needs use the following points to determine your best hardware and software. Buy the best you can afford The Storage requirement always grows over time. If you are not sure of your storage growth use a storage option that allows you to expand your storage later. (A chassis with some empty drives spaces.) A Second CPU can normally be added later but generally it is a minor cost in the overall scheme of things. Remember you are planning for 5 years growth. Make sure your chosen Server operating systems will allow for your expected user growth. When calculating the cost divide the total cost by the number of users, this figure tends to give you a different perspective on the cost. Page 14 of 14 Guide Reference: FSG-0002-01
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