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Overall considerations
Overall considerations


* Known to be compatible with Fedora (Fedora 7 / Fedora 9) which is a modern Linux distribution.
* Known to be compatible with CentOS 6 which is a modern Linux distribution.
* Low power consumption
* Low power consumption
* Operation in environmentally challenging conditions
* Operation in environmentally challenging conditions
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=Hardware known to work=
=Hardware known to work=


This hardware has been tested with the XS images - add your own, if possible with nots as to its suitability for the rule
This hardware has been tested with the XS images - add your own, if possible with notes as to its suitability for the role

Used in development and testing:


* HP/Compaq dx2250 - used by Martin Langhoff as test XS, low memory. Is RH-certified, and ships with a factory RH install.
* HP/Compaq dx2250 - used by Martin Langhoff as test XS, low memory. Is RH-certified, and ships with a factory RH install.
Line 21: Line 23:
* Dell PowerEdge SC440 - used by Martin Langhoff as test XS.
* Dell PowerEdge SC440 - used by Martin Langhoff as test XS.


Hardware being used in the field -- compare Mitch Seaton's [http://lists.laptop.org/pipermail/server-devel/2012-April/005959.html Apr 17, 2012 summary] of 4 choices:
As our work is based on a Fedora Linux, the Hardware compatibility notes for Fedora and RH systems is the best guide. See:


* Asus Eee PC (1005PEB)
* [https://hardware.redhat.com/ RedHat's Certified Hardware list]
** At Asilong Primary School in Asilong Kenya
* [http://fedoraproject.org/wiki/FAQ#Is_there_a_certification_program_for_hardware_that_works_with_Fedora.3F Notes on HCLs for Fedora and Smolt]
** Cost: $220
* [http://fedoraproject.org/wiki/HCL Fedora HCL] - appears temporarily abandoned, but Smolt
** Additional hardware: 500 GB HDD $60, USB-Ethernet Adapter $10
* Smolt stats can be of use to see whether a particular HW is used in the field with Fedora systems - see the [http://smolt.fedoraproject.org stats page] - the [https://fedorahosted.org/smoltproject page] explains how it works.
** Total number of users/laptops: 300/100
** Usual max "concurrent" users: 30
** Notes: Added AR81Family-Linux Driver to get Ethernet running, Modified /boot/grub/menu.lst to add "acpi_osi=Linux acpi_backlight=vendor" to end of Kernel command to get screen backlight to work. Contact andradupont@gmail.com for details
* Acer Aspire One (532h)
** At Asilong Primary School in Asilong Kenya
** Cost: $275
** Additional hardware: 500 GB HDD $60, USB-Ethernet Adapter $10
** Total number of users/laptops: 300/100
** Usual max "concurrent" users: 30
** Notes: Added AR81Family-Linux Driver to get Ethernet running. Contact andradupont@gmail.com for details
* MSI Wind
** Who is using it? Where?
** Cost: ??
** Additional hardware used: ?
** Total number of users/laptops: ?
** Usual max "concurrent" users: ?
** Notes: ?
* FitPC - http://en.wikipedia.org/wiki/Fit-PC
** Who is using it? Village deployment in Bhagmalpur: http://bhagmalpur.wordpress.com/ and http://wiki.laptop.org/go/OLPC_India/Bhagmalpur Where? Bhagmalpur, Uttar Pradesh, India. Google Map - http://tinyurl.com/bhagmalpur
** Total number of users/laptops: 14 XO-1 laptops.
** Usual max "concurrent" users: Can support bout 30.
** Notes: x86 server running a AMD Geode processor. Pulls 8W on the AC end. The DC end uses a 12V input. Fanless. The body is aluminum based and acts as a heat sink. We are running the FitPC with a 64GB SSD. currently runs on XS 0.6 Uses a mesh antenna for LAN and Ethernet for WAN.
* FitPC2 - http://fit-pc2.com/wiki/index.php?title=Main_Page
** Who is using it? Where?
** Cost: around USD$396
** Additional hardware used: ?
** Total number of users/laptops: ?
** Usual max "concurrent" users: ?
** Notes: ?
* LogicPro (needs link -- is it a Logic Supply machine?)
** Who is using it? Where?
** Cost: around USD$435
** Additional hardware used: ?
** Total number of users/laptops: ?
** Usual max "concurrent" users: ?
** Notes: ?
* Aleutia T1 - http://www.aleutia.com/products/t1
** Used in Afghanistan
** Cost around $320
** Additional hardware used: N/A
** Usual max "concurrent" users - 500
** Notes: Fanless / Passively cooled, accepts 12V DC power supply (e.g. could connect to solar charge controller directly without) 2GB RAM Intel Atom Processor inc. 250 GB HDD power usage between 10-15W. BIOS also has 'switch on when power is restored' feature.


Hardware that could potentially be used
==Processor==


* http://www.logicsupply.com/categories/fanless_systems
==Network Interfaces==
* Others at http://www.google.be/search?hl=en&q=fanless+linux+server
The following are the integrated networking interfaces on XS. Additional interfaces may be added to the system using the [[#Peripheral_Interfaces|peripheral interfaces]].


As our work is based on CentOS, the Hardware compatibility notes for Fedora and RHEL systems are the best guide. See:
===Wireless Mesh===
The School server will have two or three [[Active Antenna]], an 802.11b/g [http://en.wikipedia.org/wiki/Wi-Fi WiFi] wireless mesh networking interface. Each one of these serves as a mesh portal point operating on one of the three non-overlapping 802.11b channels (1, 6, and 11).


* [https://hardware.redhat.com/ RedHat's Certified Hardware list]
While connected to the school servers using detachable five meter USB cables, the Active Antennas are considered integrated as there must always be at least one of these connected for proper server operation. In the future, higher numbers (four or five) of more advanced (directional) Active Antennas may be used.
* [http://fedoraproject.org/wiki/FAQ#Is_there_a_certification_program_for_hardware_that_works_with_Fedora.3F Notes on HCLs for Fedora and Smolt]
* [http://fedoraproject.org/wiki/HCL Fedora HCL] - appears temporarily abandoned, but Smolt stats can be of use to see whether a particular HW is used in the field with Fedora systems - see the [http://smolt.fedoraproject.org stats page] - the [https://fedorahosted.org/smolt project page] explains how it works.


In general, hardware that is certified to work with RHEL, CentOS or Fedora will work. Hardware certified or known to work with Debian or Ubuntu is extremely likely to work.
These are not integrated physically into the XS school server. This allows them to be located optimally for RF transmission/reception, while the server is in a more accessible location. It also allows for greater separation of the three antennas, operating simultaneously at neighboring frequencies.


==Qualifying HW for Linux==
===Wired Networking===
Providing at least two [http://en.wikipedia.org/wiki/100baseT wired ethernet] interfaces allows for reliable, high-bandwidth connection between a [[school server]] and its internet connection (if through a [http://en.wikipedia.org/wiki/DSL DSL] or [http://en.wikipedia.org/wiki/Satellite_modem satellite modem]), other school servers, and any non-laptop computer equipment.


If the hardware is not certified and you need a strict process to ensure that it is appropriate for the task there are some useful test protocols here http://www.linux-tested.com/lnx_hardware.html - use the test protocols for:
The current plan for XS is to provide two [http://en.wikipedia.org/wiki/1000baseT 1000baseT] ports and four [http://en.wikipedia.org/wiki/100baseT 100baseT] ports on the server. The two high speed ports allow multiple servers in a school to form a high speed backbone, and the four additional ports on each server provide school network expansion without using external switches. External switches are not encouraged, due to unknown quality and the requirement of external power.


* Server / Workstation (focus on server, naturally)
Each port will be provided with two LEDs indicating link status, simplifying network debugging.
* LAN adapters - for every LAN adapter on the machine
* SCSI adapters - if the server uses SCSI adapters


The same company offers independent testing services which may be appropriate in some cases.
==Peripheral Interfaces==
The following peripheral interfaces are provided for expanding the capabilities of the school server.


=Hardware Profile=
===USB 2.0===
At least six [http://en.wikipedia.org/wiki/USB Universal Serial Bus] (USB) 2.0 interfaces should be provided for extending the storage and communication capabilities of a [[School server]].


* 1GHz+ x86 processor
This assumes that up to three external ports will be used for [[Active Antenna]], another for an external CD/DVD RW, another for a possible WAN connection, and one last one for temporary USB key or external USB drive attachment.
* 2+ GB main memory
* Four to six USB interfaces, with power for an external disk drive. Ensuring the ports can power various devices at the same time is recommended.
* One 1TB 3.5in SATA drive (smaller drives are now hard to find)
* Power and space for a second disk drive
* Two ethernet network interfaces (one will do in some cases)
* Minimal fans
** Replace them with heatsinks where possible
** Easily replaceable
* Minimal openings in the case to avoid dust, etc
* Test it in the heat - should work in up to 50 deg C


==Scaling up==
The total amount of power consumed by the USB devices will be clamped to 2.5 A at 5 Volts (12.5 W) total, aggregrated across all devices. Any single device may pull up to 1.5 A (7.5 W).


For larger schools, add RAM, disk storage and CPU (in that order). The current XS design does not need, and does not support, splitting services across many machines. See [[XS Load Testing]] for details on load testing of different XS configurations.
===PCI-Express Slot===
A short, full height PCI-Express (4 channel) expansion slot is provided internally in the XS. This slot is intended for the addition of a DVB-S receiver and demodulator, but may be used for other purposes as well.


==Server Sizing==
The power consumption of this expansion slot limited to 15 W. Exceeding this will lower the maximum ambient operating temperature of the server, and may also prevent the use of a second disk drive.


At the moment, we are recommending
==Non-Volatile Storage==
''to consider : how many drives are recommended for backups and replacement? with only 1 drive, what is the path to recovering a dead/dying drive? this may depend on quality of connection between server and upstream backup at a regional center''


* Schools with less than 40 laptops can use XS-on-XO, which requires an SD card, an external USB harddrive (at least 2GB per laptop), and a USB-Ethernet.
===Internal Disk Drive===
* Schools with up to 100 laptops: a 1GHz CPU, 1GB RAM
One internal 3.5 in. disk drive will be provided. The disk interface will be SATA (version 1 or 2). The capacity of this disk drive WILL vary, with a minimum size of 300 GB at this time.
* For up to 500 laptops: dual-core 2GHz CPU, 2~4GB RAM
* More than 500 laptops: Server-class dual CPU, 4~16GB RAM


HDD Storage needs to be sized according to the laptop's storage capacity:
A second 3.5 in. disk drive will be supported in the XS, primarily for onsite drive replacement, but also allowing storage expansion. Use of a second disk drive will significantly increase the power consumption of the server.
* XO-1: 800MB storage per laptop
* Units later than XO-1 have variable storage
** 2GB storage: 2GB per laptop
** 4GB storage: 3GB per laptop
** 8GB storage: 7GB per laptop


It is OK to underprovision storage by a modest margin. The server stores backups in an efficient mode where duplicate files are identified and consolidated.
A fan-less aluminum disk drive cooler may be worthwhile as a prevention of overheating measure.


===External Disk Drives===


''Note! For any school larger than 30 laptops, you also need careful planning of the wireless network setup.''
Additional disks may be added using the external USB 2.0 ports.


==Environmental notes==
===Flash===


The location where the HW will be deployed determines the environmental requirements. Our guidelines are as follows:
A fair amount (512 MB) of NAND Flash (solid state non-volatile) memory will be provided on the XS server to allow the operating system and minimal services to continue operation even though the primary disk drive has failed.


* Temperature: Should meet the same environmental specifications for temperature as the laptop. This is 50 C ambient.
A smaller amount (512KB) of NOR Flash will be provided for storage of configuration information and boot firmware.
* Dust: For dusty environments, the hardware should be in an enclosure without vents, have no fans, and have protection for ports such as USB ports.
* Water, humidity: For humid environments the server should be capable of long-term operation in a constantly humid (100%) environment.
* Connectors and buttons should be resistant to water and dust intrusion. Buttons should be sealed against water, and connectors located and cables dressed to prevent water intrusion.


==Other considerations==
On OTS systems Flash storage is currently not needed - or used. If you can obtain flash disks for all your OTS XS machines, do discuss it in the mailing list - it is an extremely valuable addition.we are considering using adding USB keys or SD cards to allow similar functionality.

==Power==

The power specifications of the [[School server]] are important. Many schools do not have adequate, or regular, power. While the power consumption should be minimized (30W is a good
target), consideration should be given to an integral (or optional modular) uninterruptible power supply (UPS). This is nothing more than a larger version of the laptop power supply!

In some test schools with minimal power, we are already deploying multiple (gang) battery chargers with integral UPS.

Possible methods of obtaining power are summarized in [[Battery_and_power]].

==Environmental==

===Temperature===
The [[school server]] should meet the same environmental specifications for temperature as the laptop. This is 50 C ambient.

===Water, Dust, and Salt Fog===

The server should be resistant to water spray from all directions, but does not have to survive immersion. It should be capable of long-term operation in a constantly humid (100%) environment, with salt fog and dust.

While the server will contain fans, they will externally accessible for easy replacement and under software control to conserve power.

Connectors and buttons should be resistant to water and dust intrusion. Buttons should be sealed against water, and connectors located and cables dressed to prevent water intrusion.

===Mounting===

While the school server should be designed to sit on a flat surface, it should probably
also be mountable (hangable) from a wall or post.

This shouldn't cause a problem unless the server includes batteries for a optional/modular UPS...

===Drop and Shake===

The [[school server]] should meet higher drop and shake specifications than standard consumer
desktop PCs, to account for rough transport in the delivery.

=XSX Specifications=

OTS systems builders should aim for these XSX specs:

* 1GHz+ x86 processor
* 1+ GB main memory
* Four to six USB interfaces, with power for three Marvell Wifi nodes and an external disk drive.
* One 300GB+ 3.5in SATA drive (500 GB makes more sense right now)
* Power and space for a second disk drive
* Two 100baseT network interfaces (one will do in some cases)
* Minimal fans
** replace them with heatsinks where possible
** easily replaceable
* Minimal openings in the case to avoid dust, etc
* Test it in the heat - should work in up to 50 deg C
* Test the actual network performance


* Mounting: the hardware should be able to run from a flat surface or be mounted on a wall and/or hangable.
There are many hardware platforms meeting these specifications. We are working on a recommendation for a low power version.
* Drop and Shake: should meet higher drop and shake specifications than standard consumer desktop PCs, to account for rough transport in the delivery.

Latest revision as of 05:42, 6 August 2013

  Please copy/paste "{{Translationlist | xx | origlang=en | translated={{{translated}}}}}" (where xx is ISO 639 language code for your translation) to XS Recommended Hardware/translations HowTo [ID# 290843]  +/-  


  This page is monitored by the OLPC team.

This is a description of the hardware recommended for the School server. Unlike the current laptop, the school server is currently off-the-shelf (OTS) hardware. This document outlines general criteria for the School Server and has some specific notes about what we recommend for the XS.

Overview

Overall considerations

  • Known to be compatible with CentOS 6 which is a modern Linux distribution.
  • Low power consumption
  • Operation in environmentally challenging conditions

Hardware known to work

This hardware has been tested with the XS images - add your own, if possible with notes as to its suitability for the role

Used in development and testing:

  • HP/Compaq dx2250 - used by Martin Langhoff as test XS, low memory. Is RH-certified, and ships with a factory RH install.
  • Laptop Dell Latitude D380 - used by Martin Langhoff as test XS.
  • Dell PowerEdge SC440 - used by Martin Langhoff as test XS.

Hardware being used in the field -- compare Mitch Seaton's Apr 17, 2012 summary of 4 choices:

  • Asus Eee PC (1005PEB)
    • At Asilong Primary School in Asilong Kenya
    • Cost: $220
    • Additional hardware: 500 GB HDD $60, USB-Ethernet Adapter $10
    • Total number of users/laptops: 300/100
    • Usual max "concurrent" users: 30
    • Notes: Added AR81Family-Linux Driver to get Ethernet running, Modified /boot/grub/menu.lst to add "acpi_osi=Linux acpi_backlight=vendor" to end of Kernel command to get screen backlight to work. Contact andradupont@gmail.com for details
  • Acer Aspire One (532h)
    • At Asilong Primary School in Asilong Kenya
    • Cost: $275
    • Additional hardware: 500 GB HDD $60, USB-Ethernet Adapter $10
    • Total number of users/laptops: 300/100
    • Usual max "concurrent" users: 30
    • Notes: Added AR81Family-Linux Driver to get Ethernet running. Contact andradupont@gmail.com for details
  • MSI Wind
    • Who is using it? Where?
    • Cost: ??
    • Additional hardware used: ?
    • Total number of users/laptops: ?
    • Usual max "concurrent" users: ?
    • Notes: ?
  • FitPC - http://en.wikipedia.org/wiki/Fit-PC
    • Who is using it? Village deployment in Bhagmalpur: http://bhagmalpur.wordpress.com/ and http://wiki.laptop.org/go/OLPC_India/Bhagmalpur Where? Bhagmalpur, Uttar Pradesh, India. Google Map - http://tinyurl.com/bhagmalpur
    • Total number of users/laptops: 14 XO-1 laptops.
    • Usual max "concurrent" users: Can support bout 30.
    • Notes: x86 server running a AMD Geode processor. Pulls 8W on the AC end. The DC end uses a 12V input. Fanless. The body is aluminum based and acts as a heat sink. We are running the FitPC with a 64GB SSD. currently runs on XS 0.6 Uses a mesh antenna for LAN and Ethernet for WAN.
  • FitPC2 - http://fit-pc2.com/wiki/index.php?title=Main_Page
    • Who is using it? Where?
    • Cost: around USD$396
    • Additional hardware used: ?
    • Total number of users/laptops: ?
    • Usual max "concurrent" users: ?
    • Notes: ?
  • LogicPro (needs link -- is it a Logic Supply machine?)
    • Who is using it? Where?
    • Cost: around USD$435
    • Additional hardware used: ?
    • Total number of users/laptops: ?
    • Usual max "concurrent" users: ?
    • Notes: ?
  • Aleutia T1 - http://www.aleutia.com/products/t1
    • Used in Afghanistan
    • Cost around $320
    • Additional hardware used: N/A
    • Usual max "concurrent" users - 500
    • Notes: Fanless / Passively cooled, accepts 12V DC power supply (e.g. could connect to solar charge controller directly without) 2GB RAM Intel Atom Processor inc. 250 GB HDD power usage between 10-15W. BIOS also has 'switch on when power is restored' feature.

Hardware that could potentially be used

As our work is based on CentOS, the Hardware compatibility notes for Fedora and RHEL systems are the best guide. See:

In general, hardware that is certified to work with RHEL, CentOS or Fedora will work. Hardware certified or known to work with Debian or Ubuntu is extremely likely to work.

Qualifying HW for Linux

If the hardware is not certified and you need a strict process to ensure that it is appropriate for the task there are some useful test protocols here http://www.linux-tested.com/lnx_hardware.html - use the test protocols for:

  • Server / Workstation (focus on server, naturally)
  • LAN adapters - for every LAN adapter on the machine
  • SCSI adapters - if the server uses SCSI adapters

The same company offers independent testing services which may be appropriate in some cases.

Hardware Profile

  • 1GHz+ x86 processor
  • 2+ GB main memory
  • Four to six USB interfaces, with power for an external disk drive. Ensuring the ports can power various devices at the same time is recommended.
  • One 1TB 3.5in SATA drive (smaller drives are now hard to find)
  • Power and space for a second disk drive
  • Two ethernet network interfaces (one will do in some cases)
  • Minimal fans
    • Replace them with heatsinks where possible
    • Easily replaceable
  • Minimal openings in the case to avoid dust, etc
  • Test it in the heat - should work in up to 50 deg C

Scaling up

For larger schools, add RAM, disk storage and CPU (in that order). The current XS design does not need, and does not support, splitting services across many machines. See XS Load Testing for details on load testing of different XS configurations.

Server Sizing

At the moment, we are recommending

  • Schools with less than 40 laptops can use XS-on-XO, which requires an SD card, an external USB harddrive (at least 2GB per laptop), and a USB-Ethernet.
  • Schools with up to 100 laptops: a 1GHz CPU, 1GB RAM
  • For up to 500 laptops: dual-core 2GHz CPU, 2~4GB RAM
  • More than 500 laptops: Server-class dual CPU, 4~16GB RAM

HDD Storage needs to be sized according to the laptop's storage capacity:

  • XO-1: 800MB storage per laptop
  • Units later than XO-1 have variable storage
    • 2GB storage: 2GB per laptop
    • 4GB storage: 3GB per laptop
    • 8GB storage: 7GB per laptop

It is OK to underprovision storage by a modest margin. The server stores backups in an efficient mode where duplicate files are identified and consolidated.


Note! For any school larger than 30 laptops, you also need careful planning of the wireless network setup.

Environmental notes

The location where the HW will be deployed determines the environmental requirements. Our guidelines are as follows:

  • Temperature: Should meet the same environmental specifications for temperature as the laptop. This is 50 C ambient.
  • Dust: For dusty environments, the hardware should be in an enclosure without vents, have no fans, and have protection for ports such as USB ports.
  • Water, humidity: For humid environments the server should be capable of long-term operation in a constantly humid (100%) environment.
  • Connectors and buttons should be resistant to water and dust intrusion. Buttons should be sealed against water, and connectors located and cables dressed to prevent water intrusion.

Other considerations

  • Mounting: the hardware should be able to run from a flat surface or be mounted on a wall and/or hangable.
  • Drop and Shake: should meet higher drop and shake specifications than standard consumer desktop PCs, to account for rough transport in the delivery.
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