Friday, July 30, 2010

How memory Profiles differ from VPS/Guest Host/Actual System

Device profiles are able to actually help us determine the locations of memory but also can help you profile a system. In this post Im providing some outputs of VPS/Guest Host/Actual Systems so you can see the difference.


OpenVZ:

root@bucket:~# lshw -short -class memory
H/W path Device Class Description
========================================
/0/0 memory 1GiB System memory

Above is our OpenVZ Linux Box. Not much to see here its a singular
memory channel 1GB of ram.

----------------------------------------------------------------

VirtualBox Guest Host:

dnsbox@dnsbox:~$ sudo lshw -short -class memory
[sudo] password for dnsbox:
H/W path Device Class Description
=====================================================
/0/0 memory 128KiB BIOS
/0/1 memory 511MiB System memory
/0/2/0 memory 128KiB L1 cache
/0/2/1 memory 1MiB L2 cache

Similar to the OpenVZ as in 0/1 being a singular memory channel
however abit more robust in providing Cache and L1/L2.

CPUs Cache:
/0/2/0 memory 128KiB L1 cache
/0/2/1 memory 1MiB L2 cache

----------------------------------------------------------------

Real Host:

melinko2003@workbox:~$ sudo lshw -short -class memory
H/W path Device Class Description
====================================================
/0/0 memory 128KiB BIOS
/0/3/a memory 128KiB L1 cache
/0/3/b memory 1MiB L2 cache
/0/11 memory 3GiB System Memory
/0/11/0 memory 512MiB DIMM DDR2 667 MHz (1.5 ns)
/0/11/1 memory 1GiB DIMM DDR2 667 MHz (1.5 ns)
/0/11/2 memory 1GiB DIMM DDR2 667 MHz (1.5 ns)
/0/11/3 memory 512MiB DIMM DDR2 667 MHz (1.5 ns)
/0/4/0 memory 128KiB L1 cache
/0/4/1 memory 1MiB L2 cache
/0/a memory RAM memory
/0/1.2 memory RAM memory

Above is my workstation which actually provides some indication
that it is a physical machine. How? Take a look:

/0/11 memory 3GiB System Memory
/0/11/0 memory 512MiB DIMM DDR2 667 MHz (1.5 ns)
/0/11/1 memory 1GiB DIMM DDR2 667 MHz (1.5 ns)
/0/11/2 memory 1GiB DIMM DDR2 667 MHz (1.5 ns)
/0/11/3 memory 512MiB DIMM DDR2 667 MHz (1.5 ns)

Device /0/11 is the systems PC5300 memory bank.
Device /0/11/0 is the first memory module in the bank and so on.

We can actually derive abit more information from above.This System
highly like has 2 CPU's or is a dual-core system:

First CPU's L1/L2 Cache:
/0/3/a memory 128KiB L1 cache
/0/3/b memory 1MiB L2 cache

Second CPU's L1/L2 Cache:
/0/4/0 memory 128KiB L1 cache
/0/4/1 memory 1MiB L2 cache

Of course we have BIOS:
/0/0 memory 128KiB BIOS

Some Misc Memory controls for the chipset:
/0/a memory RAM memory
/0/1.2 memory RAM memory

Thursday, July 29, 2010

Free 50GB of storage online

I was surfing around and found : https://www.adrive.com/login/signup

The Basic plan gives you 50GB of free storage. Thats CRAZY!

Wednesday, July 28, 2010

Pidgin: Facebook Plugin

Today I just happened to have stumbled upon this plugin for Pidgin. Its a plugin that allows you to chat with facebook friends :D Woot!

http://code.google.com/p/pidgin-facebookchat/

Linux: How to tell if you are Link UP

I was reviewing some of the most common interview questions asked to Linux Systems Administrators. I saw a great one:

Q. "How can you tell if an interface is link up?"

A. I guessed the old fashion one:
$>ifconfig eth0


Alternative answers:
$>ethtool eth0
Settings for eth0:
Supported ports: [ MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full

Port: MII
PHYAD: 1
Transceiver: external
Auto-negotiation: on
Supports Wake-on: g
Wake-on: d
Link detected: yes

*Interesting enough ethtool provides us some more key info see color code below for more details:
Current Duplex rate of device: [#]
Current Speed of device: [#]


$>ip link show
1: lo: loopback,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link>loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: broadcast,multicast,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000
link>ether 00:1e:8c:6e:e0:4f brd ff:ff:ff:ff:ff:ff
4: vboxnet0: broadcast,multicast\>mtu 1500 qdisc noop state DOWN qlen 1000
link>ether 0a:00:27:00:00:00 brd ff:ff:ff:ff:ff:ff

$> dmesg grep eth
[ 0.238932] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.MEM_._CRS] (Node f7019b70), AE_AML_BUFFER_LIMIT
[ 0.238957] ACPI Error (uteval-0256): Method execution failed [\_SB_.MEM_._CRS] (Node f7019b70), AE_AML_BUFFER_LIMIT
[ 2.230873] forcedeth: Reverse Engineered nForce ethernet driver. Version 0.64.
[ 2.231181] forcedeth 0000:00:07.0: PCI INT A -> Link[APCH] -> GSI 23 (level, low) -> IRQ 23
[ 2.231185] forcedeth 0000:00:07.0: setting latency timer to 64
[ 2.748879] forcedeth 0000:00:07.0: ifname eth0, PHY OUI 0x732 @ 1, addr 00:1e:8c:6e:e0:4f
[ 2.748883] forcedeth 0000:00:07.0: highdma pwrctl mgmt lnktim msi desc-v3
[ 13.217598] forcedeth 0000:00:07.0: irq 26 for MSI/MSI-X
[ 805.825023] device eth0 entered promiscuous mode

**** Note this last case will tell you if link fluxes happen.

Monday, July 26, 2010

Migrating from virtualbox-3.0 to virtualbox-3.2

I tend to have the attitude of... "If its not broken, dont fix it.
Well today after some testing over the last few weeks on a few other
systems I migrated virtualbox-3.0 to virtualbox-3.2 on my PC.

Just a small primer on how i did it:

$> sudo wget http://download.virtualbox.org/virtualbox/3.2.6/virtualbox-3.2_3.2.6-63112~Ubuntu~karmic_i386.deb
$> sudo apt-get remove virtualbox-3.0
$> sudo dpkg --install virtualbox-3.2_3.2.6-63112~Ubuntu~karmic_i386.deb
$> sudo echo "deb http://download.virtualbox.org/virtualbox/debian karmic non-free" >> /etc/apt/sources.list
$> sudo wget http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc
$> sudo apt-key add oracle_vbox.asc
$> sudo apt-get update

Enjoy!

wget: Rate limiting Downloads

Nifty little feature i've ran across recently in wget:

wget http://mysqltuner.pl/ --limit-rate=5K

Essentially what this will do is.

1) "Wget http://mysqltuner.pl/" get the contents of mysqltuner.pl website
2) "--limit-rate=5K" limit the download rate to 5K ( equivalent of 56K modem. )

Building a PC for under 200$

When I was in High School, mind you - I graduated in 2003, a computer for 200$ was far far away. You could get a name-brand CD burner for 200$ but that was about it. I think 500$ at that time was pretty reasonable for a P III 500mhz up to maybe P4 2GHZ the whole span of those 4 years.

Gaming Rigs at those times were 1K-4K depending on how cutting edge you wanted to go. The lower end gaming rigs at that time were around 800-900$ mids were in the 900$-1000$ range.

Over the last 7 almost 8 years since I've graduated I've built rigs for people on and off that have been consistently going down in price. I've actually priced out some low-end gaming rigs for around 300$, not including Monitor/keyboard/mouse.

I find mid-level gaming rigs to reach from about 400-700$ and High End still 800$+.
Systems that do not need this kind of speed and such are easily in the 200$ range.

I found this link today and thought I would share it with you :)

http://www.extremetech.com/

Tuesday, July 6, 2010

Debian: Bandwidth limiting apt

I enjoy tools like yum and apt, but wheres the control for limited bandwidth or shared bandwidth environments. Its not a magic options... or is it?

Example:
$> sudo apt-get -o Acquire::http::Dl-Limit=25 upgrade

Limits downloads to 25k. However how do i do this with a distro upgrade via cli?

sudo aptitude update &&
sudo aptitude -o Acquire::http::Dl-Limit=25 safe-upgrade &&
sudo aptitude -o Acquire::http::Dl-Limit=25 full-upgrade

Should set you at a pretty steady 25K upgrade process.. might take a couple hours but its worth it.