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64-bit chips are too much for a smartphone! Really?

After today’s Apple event, the press is on ebullition to report on it. One journalist at Gigaom has written an article on “Apple’s new 64-bit chip is too much for a smartphone, but great for a MacBook“, he explicitly stated the following:

For chip nerds the idea of 64-bit chip inside a smartphone is overkill. The benefits of a 64-bit chip is that is can take advantage of 4 gigabytes of addressable RAM, but most smartphones are barely hitting 2 or 3 GB of RAM today.

First, let’s correct his statement and then I will tell why I think that a smartphone can benefit from 64-bit chip.

Continue reading “64-bit chips are too much for a smartphone! Really?”

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Pedelecs are fast!

A quick comparison of average speeds for my daily commute, these numbers are average moving speed.

Note: Bulls is the brand name of my standard trekking bike, Raleigh is the brand name of my wife’s pedelec city/confort bike (electrical pedal-assist up to 25 km/h) and Peugeot is the brand name of our car.

Each of these modes of transport has 2 average speeds. For bicycles, one should understand the “easy” one as going slow enough to avoid too much sweating, whereas the “fast” one is when trying to be as fast as possible. For the car, it is the lowest and highest measured speed (depending on traffic).

Transport-Average-Speeds

For more information on pedelecs: Wikipedia article on Pedelec.

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Home Server – What do I want?

What service do I want to run on my Home Server?

I do have a NAS already which has the following services: File Sharing (Samba, AFS and NFS), Media Streaming Server (DLNA), VPN Server, Cloud Sync Repository. So I do not intend to have redundant services on my Home Server. What is left?

My Home Server could support:

  • Backup: Having a proper backup of all important files from the NAS and our laptop. Implementations: rdiff-backup, Box Backup, fwbackups*, duplicity*, rsnapshot or storeBackup.
  • (N)-IDS: As I have services open to the internet, I want to take some precautions and check that no exploits is taken advantage of. I am not sure this is enough, but it is the least I can do. Implementations: AIDE or Suricata.
  • DNS cache/server: I am thinking of hosting my own DNS server to perform some caching and hopefully enhance a bit the browsing experience in terms of performance. Though I would need to benchmark this to make sure I have any gain as I suspect my old router to do some caching. Implementation: dnsmasq.
  • DHCP server: My home router is a Netgear WG614 and its features for what concern DHCP are fairly limited, having my home server addressing this issue is a nice idea (until we get a better router). I could be even tightly coupled with the DNS server (see earlier bullet point) so that one could use hostname within the local network. Implementation: dnsmasq.
  • Syslog server
  • Maybe – ownCloud: maybe one day I would prefer to use an open source solution for Cloud Sync rather than the closed source one from my NAS vendor.

*: FreeBSD support is uncertain.

As one can see, I could use Linux or BSD based OS or a mixture. However, ZFS is so compelling that I am seriously considering to go for FreeBSD+jails and basta cosi! February will be the month where I try to set-up a FreeBSD server.

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My Future Home Server – Part 2

I am experimenting with different OS to find the right settings for my Home Server. I was interested by Fedora especially because there are several “Red Hat” technology which I would like to use on my server, namely: oVirt and virt-manager. Furthermore it sports a recent Linux Kernel (3.7 as of this writing) which could be beneficial if I choose Btrfs for the underlying file system.

However, testing the upgrade path from Fedora 17 to Fedora 18, I am not so thrilled by the robustness of this OS. I have managed after painfully hitting 3 different blocking bugs to recover from the upgrade and have a nice Fedora 18 up and running. But this gave me little trust in the Q&A of the community. It seems that it is not the first time such problems happen (see Fedora 11).

I am still willing to give a go to Fedora. But out of precaution, I am going to experiment first with Ubuntu (for which I had since 2006 only once an upgrade problem). I want to see the state of oVirt and virt-manager on this OS before I am making any choice.

Or maybe I forget entirely about Linux based OS, and I go for FreeBSD with several jails instead of using virtualisation. Though I would need to check the state of technologies like ownCloud, (n)IDS, etc. on this OS.

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My Future Home Server – Part 1

I have finally my Home Server built, it has its first storage hard drive and I upgraded the memory to something decent. Time to install the operating system.

I am not yet fully decided which operating system to implement on my Home Server, I would love ZFS as a file system for managing my storage, but I would still want to use Linux and not make the full switch to BSD. I decided to go for Fedora as the main OS, and install BSD in a virtual machine and see how this setup performs.

I had tried for a few month Fedora 17 in a virtual machine, I liked it, although I prefer the Debian package manager over yum, but this is really based on my own feelings and not on technical grounds.

So let’s go and install Fedora 18 (just released) on my server.

Continue reading “My Future Home Server – Part 1”

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HI (Human Intelligence) in Computer Science

The number of errors you find in forums or user groups is sometimes amazing. Here in this thread, the first answer mix up file system journaling with indexing, the second rightly tries to correct the thread but adds more errors by stating that ZFS is a journaling FS, which it isn’t. It is a transactional copy-on-write file system.

And this other thread on Ubuntu Forums is even worse. First, people do not exactly answer the question, some just express opinion/beliefs without facts, finally some are trying to base their answers on facts but those are incorrect. Example: “NTFS does not have a journal, neither is it 64 bit like Ext4.” (it is pretty hard to have that many wrong facts in one sentence, bravo!) Thanks, some users are trying to sanitize this thread (e.g. Udayakiran or falconindy), sadly their answers are flooded in the mass of bad/wrong ones.

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ZFS on Linux

In my previous post, I was stating that ZFS on Linux was not mature enough. The native ZFS port to Linux, although active, is still in release candidate stage and requires significant work to install. As for the ZFS FUSE version, it is still a 0.7 version not updated for long but it is easy to install on Ubuntu as it is available in the Software Centre (the link only works if your system supports the ‘apt:‘ scheme like on Ubuntu).

I have tried and installed the later, and although I cannot give any conclusion from a stability/reliability point of view, I was able to perform successfully the same steps I had performed on FreeBSD using ZFS.

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Btrfs – Linux answer to ZFS

Sadly ZFS on Linux is not at the same maturity level than on FreeBSD (or even Solaris). There is a FUSE implementation but it is now more than 16 month since anything happen there, and in my opinion not yet stable. Regarding native ZFS port, only one ZFS implementation for Linux is still developed by the Lawrence Livermore National Laboratory but it is still a release candidate version.
The state of ZFS on Linux is perhaps not too good today, but there is another file system in development and good support that could soon compete with ZFS, its name is btrfs (pronounce ‘butter-fs‘). Btrfs is still experimental
Yesterday, one of my virtual machines running Oracle Linux 6.3 got its root file system full, as it was configured with LVM it was not so much trouble but I wanted to try btrfs. I decided to move the /var to another partitions using btrfs. I have created a new hard disk in my VM and started it. Here is the rest of the story.

Warning: following these instructions might break your system. As an advice, create a virtual machine and experience with it before doing so on a real system.

Continue reading “Btrfs – Linux answer to ZFS”

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SSH goodies

Today I stumble upon an article regarding SSH on Oracle’s blogs.

One interesting feature I did not know is the SSH escape character ‘~’. So many times I had to open another terminal just to do one command locally before returning to the SSH session. Now this is over, just type ~^Z (a tilde followed by Ctrl-Z). Example

malmur :: ~ » uname -a
FreeBSD malmur 9.0-RELEASE-p3 FreeBSD 9.0-RELEASE-p3 #0: [...]
malmur :: ~ » ssh 192.168.78.10
unbreakable :: ~ » uname -a
Linux unbreakable.linux 2.6.39-200.29.1.el6uek.x86_64 #1 [...]
unbreakable :: ~ » ~^Z [suspend ssh]
[1]  + 2540 suspended  ssh 192.168.78.10
malmur :: ~ » fg
[1]  + 2540 continued  ssh 192.168.78.10
unbreakable :: ~ »