Server Platforms Week 11- Lecture 1

Server Market $ 46,100,000,000 ($ 46.1 Billion) Gartner

Why are Servers important Turns data into information Major impact on TCO Organisational standards

Total Cost Of Ownership Hardware capital/recurrent cost reliability cost performance cost OS software capital/recurrent costs support personnel cost training cost scalability (hardware/software) cost

Organisation standards Most organisations of any size have standards & buying arrangements with suppliers Choice of server often dictated by OS, applications and support personnel experience

Main Components in the Server Platform Processors, memory & Storage Operating system DBMS – Database Management System Middleware

Server Classes Enterprise capable servers –mainframes –large Unix, eg Sun E –large clusters Small organisational or department servers

Mainframes still important Still popular in very large organisations Strong heritage of reliability in 7x24 Move in some companies that went distributed to go back to central machines Large Internet applications may give them a new lease of life Sophisticated management software like WLM - manages workloads according to user defined priorities

IBM mainframe O/S IBM’s –OS/400 for AS/400 now eServer iSeries 400 –Z/OS - OS/390 – MVS 1974 now supports TCP/IP and Unix API & user interface –VSE/ESA – on smaller 370 machines –Z/VM for S390 Runs other operating systems as guests. These now include Linux

Other Contenders in Enterprise Market Windows NT/2000 Versions of Unix –HP’s HP-UX –IBM’s AIX –Sun’s Solaris (on E etc.) Linux

Small Enterprise & Department Servers Windows NT/2000 – 40% Linux – 27% Netware – 17% Unix – all versions – 14%

Hardware & O/S have to be evaluated together Winows NT and 2000 could display different charcteristics on the same server depending on implementations Windows NT/2000 only on Intel chips. Linux now a competitor. Unix generally on RISC chips but many different flavours

Scalability As demand on the server increases, how can it be upgraded to handle the increased load? Main components are – –Processor speed –Number of processors –Memory size and access speed –Data storage capacity and speed

Constraints on scalability Operating system support Number of processors permitted by the architecture (e.g. Compaq DL580 has max of 4, Sun E10000 has max of 64) Memory access often limits effective utilisation of processors – increase in throughput is not linear

Number and power of processors A key issue in scalability Sun’s Solaris OS can now support up to 128 but hardware architecture of Sun E10000 has 64 processor limit Windows NT/2000 now supports up to 32 processors and 64GB of memory. Originally supported 8 processors. New IA64 processor and Windows/IA architecture will address 32 bit architecture limitations. IA64 architecture will put performance as well as price pressure on the Unix/RISC based systems – within 2/3 years

Windows, Linux and 64 Bit Architecture 64 bit not designed to improve performance of 32 bit code Hence, code has to be written to take advantage of it. Linux and windows have created the OS code. Linux ahead. 64 bit applications may be the limiting software factor. Major hardware limitation is probably now the PCI bus that connects the processors and memory to storage and controllers and expansion cards. Infiniband - 2.5G+ bytes/sec IO data transfer addresses this. This technology is likely to become the data centre interconnect technology for Intel based severs

Infiniband InfiniBand Technology will be used to connect servers with remote storage and networking devices, and other servers. It will also be used inside servers for inter-processor communication (IPC) in parallel clusters.

Infiniband Architecture

Scalability and Multi processor servers Usually under the control of the one copy of the operating system But some high end machines (Sun E10000) have independent domains with each domain having its own copy of the operating system. Like two or more independent machines in the one box.

Server processor architectures Single processor Symmetric multi-processor – SMP – shared bus Symmetric multi-processor – SMP – cross bar Non Uniform Memory Access (NUMA) Clusters

SMP – Shared bus CPU Memory pool I/O Compaq DL580

SMP – shared bus is the most common With Shared Bus - –TPC benchmarks show that often manufacturers get best performance at around 50% of maximum number of processors

SMP – Cross bar CPU

Non Uniform Memory Access CPU Memory I/O Interface CPU Memory I/O Interface Cross Bar HP Super Dome & Sun E10000

Clusters Share nothing - Failover Share disk – requires distributed locking Share everything – slower than the bus of an SMP machine LAN High speed Interconnect

Clustering gives Scalability – workload can be distributed Availability – when one goes down the others take over System management – managed as a single resource – particularly disk

Disk performance Capacity continues to double each year Speed made up of three elements –Rotational latency –Seek time –Transfer rate

Storage architectures Two emerging storage architectures –SAN – Storage Area Network –NAS – Network Attached Storage SAN more closely coupled with servers NAS network orientated – higher latency High performance, large capacity, high availability, data protection, management and back-up

Network Attached Storage WEBApplicationDatabase NAS Server

Storage Area Networks WEBApplicationDatabase Fibre channel File Server