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Info Guide UNX004: Recommendations for SCO Unix 3.2v4 & OpenServer 5 Apricot has sought to provide guidance in this document on the installation and configuration of machines. We can however accept no liability or provide warranty or full support on products not supplied by Apricot directly. All modifications to a customer's machine should only be carried out only after a recent and valid backup has been identified.
(Revision: 5 - 27 September 1995) This document is designed to provide some basic guide-lines to suppliers on the preferred and recommended policies for implementing UNIX solutions on Apricot equipment. It is not intended as a 'do' and 'do not' list as such although some recommendations are forcefully stated as they are in UNIX Support's opinion in the best interests of both the supplier and the customer. We recognise that such a document cannot cover all areas but it is hoped that sufficient information and recommendations are collated here to provide a core of guide-lines. At the time of writing the current software versions which should be used on fresh installations are:
Detailed documentation on areas such as Wide Area Networking is
available in the form of Keynotes and Product Management Bulletins/Reviews. This document
collates points but is not intended to cover in depth the broader issues within product
specifications. This document will be re-issued as information and requirements dictate. Insufficient memory causing the system to swap to disk is the most common reason for performance degradation. Adequate memory should be installed to support the operating system, user processes and a sensible level of buffering between the system and peripherals. The following table describes absolute minimum configurations # required, and take no account of the memory required by each user to run applications or the requirements for system buffering.
Any system running one of the major database packages (e.g. Oracle), should have an absolute minimum configuration of 16Mb memory to allow sufficient memory for report generation and database sorts. Systems prior to UNIX 3.2v4/Open Server 3.0 should have swap areas allocated at least the size of the memory, otherwise in the event of a system crash filesystems may be trashed.
Whilst SCO UNIX 3.2v4.[12] and OpenServer 5.0 will support the use of 512Mb of memory (some earlier machines may need BIOS ROMs upgrading to support greater than 64Mb), Apricot's server platforms will support up to 256Mb of main board memory, with the exception of Shogun which will support up to 768Mb (MCA/EISA memory cards are therefore not supported), configuration of systems this large should be carried out in conjunction with UNIX Support and we strongly advise that any system with 64Mb or greater is discussed with ourselves. Please remember the memory used on AT/ISA based machines must all be
motherboard based. Memory cards installed on the AT/ISA bus are not fast enough and will
seriously impede performance. Consequently installation of these cards is not supported by
UNIX Support. Apricot SCSI hard disks are now SCSI-2 type with SCSI-2 Fast capabilities (the Shogun product is fitted as standard with a wide SCSI-3 bus). These drives are capable of raw 10MB/s (20MB/s in Shogun) transfer rates in synchronous mode across the SCSI bus, this dictates some considerations to optimise throughput of the disk subsystem. On MCA-2 servers the Adaptec AHA-1640 16-bit SCSI controller does not have the capability to fully optimise the new high speed hard disks, it is therefore important to install the Buslogic MDA 32-bit SCSI controller on 486 systems and essential on Pentium FT//s and FT//e. The FT//ex EISA server has an integrated Adaptec 7770 (2742) dual channel SCSI interface with performance approaching the MCA-2 Buslogic card. The Shogun has dual onboard Adaptec 7870 controllers utilising a wide SCSI-3 configuration, giving double the performance of equivalent 8-bit SCSI setups. Where two drives can be used instead of one it is often the best solution, this is simply because the drives can be accessed in parallel. The best performance with the fastest drives is achieved by dedicating a SCSI channel or controller to each pair of drives. We recommend the use of several filesystems wherever possible as this assists performance and system rebuild in the event of crash. Unless a customer has a particularly large application the table below provides sensible approximations. Root filesystems of much more than 250Mb are inadvisable as they are then becoming data partitions. The swap area will of course take up a significant amount of space which should be calculated before the precise configuration of the filesystems is made.
It should always be borne in mind that if the operating system is ever to be reinstalled it is least disruptive if all the data is on separate partitions. Please remember hard disks of greater than 1.0Gb are only supported on SCO UNIX 3.2v4/Open Server 3.0/5.0 and even with these versions the root filesystem must reside in the first 1024 cylinders. Multiple disk configurations should also approximate to the table above where the space allocated for the root filesystem is assigned to a new filesystem. A number of machines are now being configured with multiple SCSI cards and hard disks. The table below gives suggested SCSI ID settings for five drives and two tape units (SCSI cards whether Buslogic or Adaptec use SCSI ID 7). All SCSI devices supplied by Apricot use LUN (Logical Unit Number) 0.
The values in the table above can be used for configurations for both
one and two controller cards for up to 5 drives. We recommend that tape and CD-ROM units
are currently connected to the first SCSI card along with the root hard disk, with
additional hard disks being balanced between the SCSI cards. Configurations using more
than two SCSI controllers /controller cards should be discussed with UNIX Support. Shogun
has 2 Adaptec 7870 onboard controllers, and is a case in point. Systems configured with
DPT RAID cards, normally have the disks configured on the card and the CD-ROM/tape drive
configured on the on-board Adaptec controller. System back-ups and data back-ups are absolutely essential and MUST be taken. Databases, Accounts, and Manufacturing packages in particular should be closed down prior to back-ups commencing to ensure data and index files remain consistent. In general no user activity should take place when full system or data back-ups take place, which is why the best time for these procedures is during the night when low activity is more usual. Back-up scripts controlled by cron which send mail to users allow both back-up and verification to be done at low usage times and the results to be supplied to the system administrator. Back-ups can be considered to come in three forms:-
Data back-ups are clearly vital. A customer's data must not under any circumstances be put at risk. It is therefore in some cases necessary to impose back-ups on a customer if he/she fails to comprehend their importance. Data back-ups should ordinarily be taken daily or in some very busy environments during the lunch break as well as during the night. Data back-ups should be cycled on a minimum of five tapes for a five day working week using ten tapes if lunch-time back-ups are also taken. On a seven day working week the requirement would be seven and fourteen tapes. Full system back-ups should obviously follow the guide-lines for data back-ups. Some sites may also wish to take monthly, quarterly or annual back-ups to provide specific time/date based archives. All back-ups should use cpio or pcpio. Tar and ptar are unsuitable for commercially critical back-ups and operating system back-ups as these utilities do not archive empty directories or device files and the tar verification phase does not check the data blocks. Apricot provide a general purpose backup script called abackup which is recommended. This can be found on the Apricot UNIX Utilities floppy. Also, refer to Info Guide UNX003 for a detailed description of backup/restore methods. All server platforms must be supplied with one or more of the tape options below. The XEN-LS II and XEN-PC both support the Adaptec 1510 SCSI card (under 3.2v4 UNIX and OpenServer 5.0) which can make use of the internal tape options detailed in the following table. Alternatively the external Archive QIC-150 units can be used under UNIX or Xenix. The availability of SCO UNIX and OpenServer 5.0 on ¼" tape cartridge is an additional reason for the use of ¼" media devices in small desktop systems where CD-ROM and a tape unit cannot be fitted. With OpenServer 5.0, it is worth noting that the main installation software is supplied as default on CD-ROM, but is available on QIC format if requested. Apricot will not be supplying SCO OpenServer 5.0 on floppy diskettes. On the EPx Desktop Server it is worth considering the Adaptec 1542(AT/ISA) or 2742(EISA) cards which will provide SCSI drive support in addition to tape/CD-ROM. Note that problems have been seen using the Adaptec 1742 card in the EPx. It is important to ensure that the back-up mechanism supplied with the machine is of sufficient capacity to back-up all the customers data onto one tape, this makes archiving and documented procedures much simpler.
It is also recommended that some copies of each back-up tape are kept either off site or in a fire safe. It cannot be stressed too strongly the importance of a sensible archiving policy. The Exabyte very high capacity back-up units (using 8mm media) were tested some time ago by Apricot and found to work successfully. We have also examined the newer 5Gb Exabyte 8500 with SCO UNIX V/386 3.2v4.0 and concluded it too works satisfactorily. The 2.5Gb Exabyte 8200 is now one of the supported back-up devices on SCO UNIX 3.2v4 and this driver also successfully controls the 8500. The half-height Exabyte 8205 has greater than 5Gb of capacity (the exact capacity is dependent on how much the data can be compressed), has briefly been tested in Apricot FTs machines and found to work well within the time available for testing. Exabyte products are available from Phase IV Systems (see glossary). SCO UNIX/OpenServer 5.0 now supports the Exabyte 4000 series drives. (needs UOD376C on 3.2v4.2) Some customers do require ½" tape units, these can be supplied either to run off separate cards or off the Adaptec SCSI card. We have evaluated a ½" unit from Phase IV Systems which works entirely correctly on SCO UNIX V/386 3.2v4.0 using the external SCSI connection of the Adaptec card. Slight inconsistencies on earlier SCO UNIX revisions lead us to advise this product is only installed with SCO UNIX V/386 3.2v4 or later. We have in the past successfully examined a ½" unit from Digi-Data using SCO UNIX V/386 3.2v2.0, this should also correctly run on 3.2v4 and OpenServer 5.0 systems. DDS and DDS II DAT tape drives are fully supported by Apricot on SCO 3.2v4 and OpenServer 5.0. It is important to remember however that backups made on one format may not necessarily be readable on another. This is the case particularly between drives using compression, and those that don't. Additionally, we have seen cases where putting a compressed tape in a non-compressing drive has actually hung the tape drive, necessitating a re-boot to free it up. The Shogun will also be supporting the use of the DEC DLT series drives,
although at the time of writing, these have not been fully tested under SCO software. The current primarily supported cards in new equipment are the Specialix SI/PS & SI cards. Note that only the Specialix RIO configuration is supported on the Shogun. A maximum of two cards (which equates to a maximum of 64 RS232C ports) is supported in MCA/EISA servers (all FT// series) and a single card configuration is supported in desktop systems (XEN-LS II/XEN-PC and EPx). All Specialix TA boxes must be at revision ECO-100 or later. The recommended serial cable is
It is essential all cables are shielded, the RS232C specification supports cables up to 50ft from the source running at a speed of 9600 baud. In practice higher distances and speeds can be achieved although they are not supported without the use of line drivers (these should be externally powered to avoid increasing the current drawn through the Specialix cards and consequently the bus). For modem support on Specialix lines use:
Diagnostic modems really should be supplied on all server platforms. These installations are often supporting considerable numbers of users and it is essential that adequate support can be given to a customer in a short time frame. The list below gives the known and supported modems for use on Specialix serial cards. Use of the on board serial port is now discouraged as the Specialix software and hardware have proved exceptionally reliable and the intelligence of the Specialix hardware limits the loading on the main processor. The following table lists the supported modems.
Please note it is impractical to use internal modems on Xenix and UNIX and is not supported by Apricot or SCO. Apricot's Specialix offering now includes two other options for direct serial connectivity (Ethernet options are discussed in the next section). The XIO product range is a second generation modular serial solution offering higher throughput on up to 32 connections per card using 4 terminal adapters each of which is capable of supporting a parallel port. The XIO range is however a higher cost than our current SI and SI/PS solutions but can be expected to supersede them in time. The Specialix RIO product is a considerably more sophisticated serial solution which offers distributed ports. Each terminal adapter supports 8 ports (one of which can be parallel), each card has 4 ports for connection of terminal adapters, each adapter also has four ports for connection of other adapters or to the card. It is possible to connect 16 terminal adapters to a single RIO card giving a maximum of 128 ports, with smaller numbers of ports it is possible to build a fault tolerant configuration. Only one RIO card should be installed in Apricot equipment without discussion with ourselves, the RIO card takes 64Kb of the addressable memory range on MCA/EISA servers which may significantly restrict the additional configuration options. Each terminal adapter can be located up to 75m from its neighbours or the host card and by means of fibre-optics these distances can be increased to 1km. This means true distributed serial connectivity can be implemented at sites where an Ethernet backbone is either unavailable or not desirable due to existing hardware investments.
The above configuration shows how to configure the maximum of 128 connections from a single RIO host card with sixteen RIO terminal adapters (RTA). This configuration is only valid in highly specified FT//s or in some cases FT//e systems.
In the example above the links labelled F are fail-safe links allowing a
break to occur between some of the RTA's with no detrimental effect on the users. It is
not possible to build a fail-safe configuration with 128 connections. Installations of SCO TCP/IP and SCO NFS need monitoring initially to ensure streams resources are correctly configured. Overflow of kernel buffers can cause system panics, however, this has been greatly reduced with SCO OpenServer 5.0, as the buffers dynamically grow as needed. All servers should ideally use the 3Com Etherlink III family of cards to reduce the loading on the CPU and offer the best performance across the network. On desktop machines such as the XEN-PCLS, the AMD PCnet32 is used. SCO OpenServer 5.0 will support PCI and 100Mbit cards. Multiple 3C527B/Etherlink III cards can be installed on servers where network performance is critical. (Note that the 3C527B only works under SCO 3.2v4.x / TCP 1.2.x) Please consult UNIX Support for more details on multi-card
installations. A summary of where to find drivers for Apricot current or previous
interfaces is given below:-
Apricot UNIX Support has evaluated two terminal servers at this time. The Chase IOLAN is an established product which we have used for a number of purposes internally. We have now also examined within Unix Support the Specialix MTS terminal server which we can also recommend. The Specialix solution has the additional benefit of being field upgradeable from the standard 8 ports to 16, 24 and 32 ports, it can also have a parallel port fitted, replacing one of the RS232 connections on each bank of 8 ports. Chase and Specialix support both BNC (thin) and AUI (thick) Ethernet. Some additional software is required with most of the terminal servers
to allow successful printing. The Specialix MTS requires binaries to expand tabs and carry
out mapping of newline to newline and carriage return. UNIX Support can provide a binary
to control printing via the Chase IOLAN, this binary has also been configured to work with
the 3Com CS/2100 and the UnISo terminal servers. Further advice is available on terminal
servers from UNIX Support. Over the years SCO have routinely issued supplements for each operating system or package. A summary of those particularly applicable to more recent operating system revisions is given in the following table. Where a supplement is indicated as Mandatory, Apricot expects the customer's machine(s) to be brought up to this level at the next available visit.
* Column S indicates the UNIX Support position of this fix, M =
Mandatory, R = Recommended and O = Optional. Please note that NFS is a product which can only be run on UNIX and
requires TCP/IP to be preloaded. Apricot's suggested solution consists of the use of the DPT 2122 card on older VESA based systems, such as the J3 based FT//ex. We have tried such a configuration in Technical Support, and found it to work satisfactorily with the drives supplied by Apricot for that system.. The card is available from Ambar Systems on (01296) 435511. Additionally, this card should have the cache module, 4Mb ECC cache SIMM, and RAID module fitted. For FTe and FTs systems, we recommend the use of the Veritas volume manager. Contact Veritas in the USA on (408) 727-1222 for UK distributors. For later systems such as FT//ex 1000,2000 and Shogun, the DPT SmartRAID 3224 card is the supported option. This controller will support RAID 0 (disk striping), RAID 1 (disk mirroring) and RAID 5 (disk striping with parity striped across drives). Where customers express a requirement for RAID this is now our preferred solution. More details are available on request but SCO UNIX 3.2v4.2 and Open Server 3.0 is fully supported with this controller. At the time of writing, we are evaluating the beta release of the OpenServer 5.0 SCSI driver and manager software, that will be supported with this controller. However on MCA-2 servers no hardware solution can be recommended by
Apricot and we therefore advise the use of Virtual Disk Manager for OpenServer 5.0, and
Veritas Volume Manager for earlier releases, as stated above. Some older Maxtor 4000 and
8000 series hard disks may not be fully supported by RAID software solutions, we therefore
recommend installation only on currently shipping hard disks. This area is primarily the province of specialist suppliers. In the X.25 arena there are a number of suppliers and products covered in a comprehensive keynote from our product management colleagues. At this time Symicron supply a card which takes 64Kb of the addressable 128Kb for cards installed on the MCA bus, this imposes severe limitations on the other cards which can be supplied in machines. The Software Forge have a card which only takes 32Kb of addressable RAM and has been successfully installed in a number of systems. Software Forge also offer TCP/IP routing capabilities over X.25 for those customers who desire it. UNIX Support have an established link to Software Forge who are our preferred X.25 supplier. In the ICL arena, Bolden James provide a package called Sabre 386 to
link SCO UNIX to ICL mainframes. It is essential that the kernel is tuned to the requirements of the customer and the applications he/she is running. The kernel parameter NOFILES should not be altered from 60 on systems running TCP/IP versions earlier than 1.2.0. Similarly the parameter NHINODE should not be altered from 128 when running NFS 1.1.1 on SCO UNIX 3.2v4 systems. Some of the kernel parameters to pay attention to are given in the following table, where the settings column indicates some minimum recommendations. The tick indicates that this parameter exists as a manually tuneable parameter for SCO OpenServer 5, as most kernel parameters are dynamically tuned on OSR5.
The NBUF, MAXBUF and NHBUF parameters significantly alter the performance of the machine. NBUF fixes the size of the buffer cache whereas MAXBUF sets the maximum and lets the kernel work out a practical setting. Setting NBUF too high may prevent a system functioning efficiently due to a lack of user memory. It is almost impossible to give a universal set of values for the kernel, the values given below will provide very significant improvements over the throughput of a default SCO UNIX installation. These values do not cover the tuning of the kernel for network utilisation.
The NBLK parameters require different values for different Ethernet card drivers. Drivers for the 3C527 for instance use a high number of NBLK2048. To identify which parameters should be increased from the default use one of the options below:-
The Unix system monitor u386mon utility enables the monitoring of
memory, swap and hard disk usage along with a number of other kernel parameters. The
utility is available via the MS-DOS Bulletin board system (areas 27 & 39) and via the
UNIX Support server. We strongly recommend the use of this product for system monitoring
and analysis, the product is supplied free of charge to encourage wide usage. The SCO UNIX
System Administrator's Guide also gives considerable advice in the area of kernel tuning. The following simple tables provide advisory settings for particular hardware in Apricot equipment. In most cases other settings can be used but these tables have been generated to provide guidance where required.
Please also remember the following points:-
These few points may prove helpful in the configuration of systems.
SCO OpenServer Release 5.0 Introduction and Features SCO OpenServer 5.0 is the latest development in UNIX operating systems from SCO. The new product consists of 3 base Operating System products:
Enterprise System Host System Basically, OpenServer comes in two main flavours, Enterprise that has all the networking protocols built in, and Host which has no networking capability. In addition, there is: Desktop System New Features
SCO OpenServer 5.0 is supplied on CD-ROM as standard, but is available on QIC if requested. Floppy installation is a possibility, but is not a supported option from Apricot, and as such will not be available. The installation CD or tape comes supplied with a boot disk and currently, a patch disk that must be installed after installation. This is done via the new patch management option within SCOAdmin. It is recommended that any installation be done fully interactively in order to set up the hard disk partitioning correctly. Additionally, if installation is done on a machine using the Adaptec 7870 controller, ensure that the upgraded btld is installed before attempting reboot. The driver required is alad_os5.Z and should replace /etc/conf/pack.d/alad/Driver.o Refer to IPB 3183 for details.
Apricot Support staff are available on a chargeable basis. We would request that where a customer/channel wish to make use of this service seven days notice is given if possible. A basic guide to charges is provided below:-
All relevant fixes from SCO are provided on the Internet server - ftp.apricot.co.uk, or at the World Wide Web URL - http://www.mitsubishi-computers.com, and also UNIX UUCP server, and MS-DOS Bulletin board for download free of charge. The failure of disks and potential virus issues necessitates we do not accept disks for software. Apricot will use new disks from internal stocks to service software requests. Apricot machine installations are based on the charges above and incorporate testing of each component with the Operating system and the installation of any appropriate SCO supplements or fixes. The internal Apricot network allows us particularly to test installations involving network products prior to delivery on a customer site. An installation service is also available for non-Apricot equipment (with charges being negotiated at the time). Electronic mail to Apricot can be setup via Microsoft Mail, or via the
Internet to enable contact with all Apricot staff. Either method is a requirement for
Apricot approved maintainers wishing to support the Shogun product.
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