My thoughts on life, the universe and beer

Howdy!

I have been using GNU Screen for loads of stuff to save me from a unreliable connection, however recently I began to use it for IRCing.

The biggest reason here is that I don’t always have a IRC client available or I would have some issues connecting to my bnc due to firewalls etc, but there is always a SSH client somewhere in reach .

What everyone who are going to IRC from a screen session will learn very quickly is that screen does not allow you to scroll up and down normally. However, you can do it quite easily.

1. Add this to your $HOME/.screenrc:
defscrollback 5000
This gives you 5000 lines in your scrollback buffer.

2. Jump into a new screen session, cat some long config file and try this:
Press: CTRL+A+ESC
This will send you to Copy Mode.
Now you can try these key combinations:
CTRL+u – Scrolls a half page up.
CTRL+b – Scrolls a full page up.
CTRL+d – Scrolls a half page down.
CTRL+f – Scrolls the full page down.

To leave copy mode you can just press ESC.

Now, you can scroll away and read what people have been saying about you while you were away!

Hope this helps you!
Bgrds,
Finnzi

Howdy,

A very neat link on Linux/VirtIO: here

Bgrds,
Finnzi

Bah!

A Seagate 320GB sata HDD started giving me bad sector recently. I am currently cloning it to a 500GB disk i had in the same computer with a tool called CloneZilla. I have used it quite a few times to create a image of a disk before OS upgrades and also for cloning hdd’s between drives.

If you need a replacement for Norton Ghost please check it out. It even has the possibility to multicast images on a large network!

Bgrds,
Finnzi

YAY!

See this link: http://dag.wieers.com/blog/red-hat-backported-io-accounting-to-rhel5 and http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5.4/html-single/Release_Notes/

We’re getting I/O Accounting (per process I/O accounting) in the next month or two! This is a much needed feature for the Linux Enterprise platforms. Personally i have been waiting for this feature since i first saw my first Glance Plus install…..;)

Linux has been proofing it self as a big player in the Enterprise area, and with the I/O accounting code added this will make my life a lot easier when debugging multi-oracle instances performance issues

Well…just wanted to brag about this sweet feature of the RHEL kernel

Bgrds,
Finnzi

Howdy,

Yesterday at work i had to extend a disk on a Lotus Domino server that i was not able to stop. Since the LUN was on a LVM group i knew i could extend the VG without disrupting the Domino server but i did not just want to add a new LUN to the VG since that tends to get messy after a while.

So i decided to try out pvmove. I had heard some horror stories that it would take ages etc, but since Red Hat supports the tool i decided to try it.

Amazingly i was able to add a new LUN to the VG (one without a partition for a easy resize experience later). The original PV was around 128GB, and it took about 25-35 minutes to move all the data of the PV!

While HP-UX administrators tend to tell you to just use mirroring instead of pvmove, and then just break the mirror and remove the smaller LUN, i found out that what pvmove really does is to create a mirror, and then copy the extends and in the end, remove the mirror. Just make sure you either background the pvmove task or run it in a screen session, preferably with -i 5!

I’m off to watch some telly….

Bgrds,
Finnzi

Man …

I was asked to work today on a holiday. Why? I have to extend a filesystem on a HP-UX 11.31 machine.

Amazingly HP does not include online resizing in the base install of HP-UX. Common people! You have to buy IA64 machines from HP, you have to buy the foundation operating system (minimalistic feature version of HP-UX), but you can not extend filesystems on the fly.

This is one of the reason i think Linux is going to rule the future. RHEL includes this. Hell, OpenSolaris gives you the features needed to extend ZFS free. Even IBM includes these features in AIX!

My point is, that in my free (or paid for subscription of RHEL) install of Linux (even on a IA64 machine) i can mirror disks with LVM, i can resize filesystems, i can even migrate data between disk arrays on-the-fly.

HP really needs to start taking care of they’re customers and stop charging for such a simple feature. Enterprise customers will probably start looking into other operating systems now when the budgets are getting tighter.

Hell, why am i even crying about this, i get my overtime, Linux ends up gaining more respect with enterprise customers and everybody wins!

Well, i have to get going, work calls….

*UPDATE*: While doing some partition resizing on my Macbook i realized that i can resize hfs+ on-the-fly (both shrink and extend). I do realize hfs+ is not the most advanced filesystem out there but common, this is a operating system mainly focused on home usage! HP-UX is a enterprise grade UNIX operating system. C’mon HP!

Bgrds,
Finnzi

Howdy,

Woke up early today. Got my coffee mug filled up, decided to relax in my fancy sofa, got my macbook and went on to read up on some mailing lists (Yeah….i like to read up on mailing lists…now beat it!). Now the first post i read was from a person trying to add a specific functionality to a certain software product. The mail was something like this:

“Please teach me howto to X”
Bgrds,
Unamed Person

Now, the software product in question here is a widely used piece of high availability clustering software. The manufacturer has some good manuals on how to do X and a quick google will give you a awful lot of information on how to do this.

What i am trying to say here: RTFM or at least TRY to Google your issue before posting onto a list. I’m betting around 70% of the users on the mailing lists are system administrators that are already working in a 150% job and would really like to help, but they won’t help if you don’t even try to read the bloody manual!

Bleh….maybe i have not had enough coffee in the morning….but people…TRY!

I’m off to read up on more mailing lists….wish me luck!

Bgrds,
Finnzi

Using “ps axm” can show you all threads of all processes…neat!

Howdy,

I’m wondering if it is better to replace a HA cluster running RHCS, serving GFS through NFS & MySQL through Active/Standby clustering with:

All the clients of this cluster are IBM HS21 blades, running CentOS5, booting of SAN and have 2x1Gbit ethernet interfaces in a bond mode 1.

Those blades could just use OCFS2 instead of NFS, and instead of running MySQL in a Active/Passive setup we could just as well use MySQL MMM.

I guess i have something to think about while on my christmas holiday!

Bgrds,
Finnzi

Man …

Yesterday & today i have been preparing a IBM JS12 machine for a client. I got a JS20 machine few weeks ago to use in a test and was not extremly happy with the hardware, but the OS, AIX 5.3, has been a surprise. I find all patching and installation tasks to be very easy to perform. I have been a bit burned from my experience with HP-UX & Solaris (i do not consider my self a expert on the OS’s, but have done some HP-UX work for few clients and do run some MC/ServiceGuard clusters.

It is also quite nice to not have to go through hoops to install software like Oracle (Trying to find a consistent guide of what RPMS should be installed on a RHEL5 system for Oracle has not been very easy to find, but somehow i managed to create one). I had to install 2 packages to be able to install Oracle on my new install of AIX 5.3 TL8.

Now, i am not saying i loooove everything about AIX but IBM have made something really good here. Combined with Power6 (and soon, Power7) i am pretty sure i will start consider AIX for my projects at work where i find that i need more power, more stability & more maturity then Linux can offer. Again, i am not saying Linux is not mature enough for most of my projects, but there are places where i could really use AIX.

HACMP is one of the products which can replace MC/ServiceGuard, you do not need a license for basic things like mirroring your volume groups (in software) and you will probably never ever have a bug in a licensing code stopping you from forcing an unmount of a VXFS filesystem on your AIX system (HINT HINT, HP-UX anyone?).

Well ….I’m off….
Laters,

Finnzi