Tag Archives: Hardware

Creating and mounting a partition lager than 2 TB in Linux

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This might be basics for some, but it’s a good thing to have bookmarked for the day you might need it. It helped me a lot.

Why can I only use 2 TB (TeraByte) of my 2+ TB drive in linux?

The answer is really simple. I guess you formatted the drive using “fdisk” which use a ms-dos partition table.
MS-dos partition table (MBR) is 32 bit, and thereby it can’t handle anything above 2 TeraBytes

How to create a partition above 2TB in linux

To fully use your 2+TB harddrive, you have to use a partition table that supports it. We now know that the MS-DOS partition table (MBR) does not, so what should you use instead? GPT.
GPT supports up to 9.4 ZB (ZetaByte). That’s 9895604649984 GB (GigaByte)!. It’s pretty safe to say, that you will not hit this limit in the near future.
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Find all HP ILO interfaces on a subnet in Linux

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By default, HP’s ILO interfaces are set to DHCP.
Yes you could go into your router to see which DHCP lease it got, but here is a much more easy solution that you can use anywhere, even though you don’t have access to the router/DHCP server.

Requirements

You don’t need much. What you need on your Linux computer for this to work is:

  • sudo (You only need this if you are not logged in as root)
  • nmap

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Flashing the LSI Megaraid M1015 SAS/SATA controller firmware

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If someone would like to take pictures and screenshots of the process for me that I can put into the guide, that would be great. Since I do not have a running Windows computer at the moment I can’t make them myself. (post a comment and I will contact you). This line will be removed once I have the pictures i need.
Some guys a reddit.com requested that I made a quick guide on how to flash a LSI Megaraid M1015 SAS/SATA controller for pass-through firmware.
This guide will be on how to flash it for pass-through OR raid functions, since it’s the same method but with two different files.
I will supply you with the files needed as well.

What you need to flash the Megaraid M1015

You will need the following:

  • A Windows XP/vista/7 computer (I have only tested on Windows 7)
  • Package containing the firmware and tools for flashing, you can download it here
  • A USB stick (I Think 256MB is more than enough), it should not contain any data, since we need to format it!
  • This program (hp flashing utility, easy way to make bootable usb DOS usb stick)
  • Win98 boot files, you can download that here

That’s all you need except for the raid controller itself and a computer/server to install it in!
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Realtek network cards and VMware ESXi 5.5

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Yesterday I decided to upgrade my two ESXi servers from ESXi 5.1 to ESXi 5.5 since the update came out some time ago.
The upgrade from ESXi 5.0 to ESXi 5.1 went great, without any problems. But this time, that is not the case.
My two ESXi servers are white boxes made of the following hardware:

  • Motherboard: MSI Z87-G43 (http://www.msi.com/product/mb/Z87-G43.html)
  • CPU: i5-4670K (http://ark.intel.com/products/75048/)
  • RAM: Kingston HyperX DDR3 1600MHz, 8Gb * 2(16GB total) (http://www.newegg.com/Product/Product.aspx?Item=N82E16820104173)

The problem was the motherboard that ships with an onboard Realtek 8111E network adapter.
This problem has been verified to be the same with Realtek 8168 and Realtek 8169.
The reason for this, is that VMware removed the drivers from the new ESXi 5.5 iso.
In this post I will show you how to get ESXi 5.5 working with the Realtek network adapters.
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How to configure a distributed file system with replication using GlusterFS

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Distributed file system between multiple servers is a thing I have planned for a long time, but I never got around to it because I first had to find the right filesystem for it.
After a lot of research, I found that GlusterFS was the right file system for me.
My plan was to use a distributed filesystem to share the content of my webservers to make sure all my webservers had the same content on their pages at all time and using some sort of high availability to make sure the content was always there.
To this I used a tool in Linux called Lsyncd before I set up my GlusterFS cluster, this worked well and did live syncing of all the servers using rsync. But there was one problem with it.
If I uploaded a lot of files (20+) to one webserver, and it started to sync to the other webserver before I was finished copying, the result would be that some of the files ended up corrupt, and this was a problem for me!

My distributed file system overview

Here is the overview of the setup I am making, it’s not pretty but I’m sure it’s a lot more easy to explain the setup using a simple mspaint drawing than with text!
GlusterFS distributed file system overview
As you can see in the picture above, I have build this with high availability in mind, since I want my websites to always be up and running!
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Temperature measuring using Linux and Raspberry Pi

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The story

I have a small server room, with some rack servers, NAS’s, VMware ESXi’s and other fun stuff, but I had one problems.. in the summer it got really hot, and I had to open the window to let fresh air in, and the old out to lower the temperature again, but I never knew when it was too hot, so i had to drive by the server room once or twice a day to manually feel if it was too hot..
This was a problem, because sometimes I was not home, or sometimes I forgot, or just had no time to drive by to check the temp.
Having a temperature sensor in the room, from a freezer or something like that didn’t help me much, since I still had to drive by to check it manually.
So I had to make something I was able to get the room temperature from, over the internet/lan, and thats when I decided to make my network thermometer.
I looked for weeks on the internet for a good guide about this, but none of them worked. so I decided to write my own to help others with the same problem out.

This post will be about

How to make your own network thermometer, using open source software and a cheap USB temperature sensor!
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MySQL data on secondary hard disk

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Having your MySQL data on a separate partition is important, why?

Having your MySQL data on a separate partition is important because when your root partition fills up and no space is left, your system won’t be able to boot and might crash when running, you then have to boot from a recovery disk to remove files before you can boot on your normal system again.
This is critical for servers that you can’t allow to be down for an hour or two!

The solution

The solution is easy, you just move your MySQL data to a separate partition, and this problem won’t occur any longer, the only thing that happens when you run out of space, is that the MySQL can’t write any new data to the database, which is better than the entire system crashing and being unable to boot.
In this guide i will show you how to make the changes needed to get this problem resolved.
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