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Les Mikesell (lesmik...@gmail.com)

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1) Les Mikesell Re: [CentOS] howto transfer all configuration between 2 remote dedicated servers?
| +1 vote
What I've always wanted is a tool that would manage a group of machine configurations as branches...
CentOS
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Dag Wieers wrote:
>
>> But my real question is: How can I get a list of files in the whole
>> filesystem that were added or modified compared to all the files that
>> come
>> from rpms?
>> Is there a script for doing such a thing?
>
> You may be interested in a tool I wrote some time ago that makes a
> hardware and software snapshot of a system, including the latent
> configuration in memory (like routing information or firewall rules).
>
> It creates the snapshots in single compressed text files periodically
> (hourly, daily, weekly, monthly from cron) that can be diffed. And it
> allows to send out diffs to one or more email-addresses if configured to
> do so.
>
> It was written with multiple use cases in mind:
>
> - compare identical systems (eg. nodes in a cluster, or when migrating
>    servers)
>
> - mail changes to a group of co-maintaining sysadmins (so configuration
> changes are communicated and if needed acted upon)
>
> - backing up a complete system's HW/SW configuration and making diffs
> with past configurations for troubleshooting problems
>
> - taking system configurations with you (as a consultant or support
> organisation it is nice to follow-up on system changes made
>    by the customer)
>
> The tool is called dconf. You can find it in RPMforge.
>
> The tool is as good as its configuration. The default configuration
> already contains a lot for RHEL/CentOS, but it could use more people
> defining more tools/configuration file. And I am open for improving the
> tool beyond what it does now.
>
> Feedback appreciated,

What I've always wanted is a tool that would manage a group of machine
configurations as branches in subversion so the tool itself wouldn't
need any diffing capability and could be wrapped by viewvc for web
browsing, mesh nicely with router and other text base config management,
etc.   By 'configurations', on RPM based machines, I'd want the package 
list exported in a form that yum or kickstart could use to re-create the
set (and I suppose to get this right you also have to build a local
repository containing all of them because rpm/yum  are too dumb to know 
where they came from, given multiple repositories), and copies of all
the files in /etc/ and other optional places that are not exactly as
installed from an RPM.

Is such a thing feasible, and if you can get that far, can it become a
'configuration factory' where you'd copy the starting config close to
what you want to a new branch, edit a few files for the needed changes
to produce a new machine, commit them, and then have a tool build that
machine or a disk image of it?   What I'm after is something that will 
let me make on-the-fly changes to any running machine, but pull those
changes back to a central management tool in a way that makes it easy to
see differences across time or between similar machines, and to use the
current setup of any machine as the starting point for a new one.

Most of the tools I've seen so far involve their own abstractions to
describe configurations and require them to be made at the central
management tool.  That's not what I want.  I want to do configurations 
using the native setup on one or more machines whether or not the
management tool has an abstraction for it and have a way to use that
going forward and to track differences without any intermediate
abstractions.  I suppose in a way the version control's branch/rev/tag 
mechanism becomes an abstraction for the whole machine state at a point
in time.

--
   Les Mikesell
     [email protected: lesmik...@gmail.com]


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2) Les Mikesell Re: [CentOS] how can I stress a server?
| +1 vote
I kind of lost track of this thread and missed any useful performance information if you posted it....
CentOS
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Rudi Ahlers wrote:
>
> I'm sitting with a very expensive paper weight right now, and I don't
> know what todo. The same websites are running very well on a machine
> with a Gigabyte G31MX-S motherboard + 4GB DDRII 800 RAM + C2D 6750
> CPU. This is what baffles me, how can the same load on a slower
> machine work fine, but on the faster one not?
>

I kind of lost track of this thread and missed any useful performance
information if you posted it.  Is this the same machine that has 
mysterious crashes?  If so, I would just give up, or replace the RAM and 
power supply and then give up.

Performance wise, what kind of load does it have?  Most servers that 
aren't doing graphics or number crunching are limited by disk i/o, not
cpu so the disks and controllers are the interesting things to compare
although if the controller requires a lot of CPU intervention (ide, sata
in some modes) it may look like a cpu problem.

--
   Les Mikesell
    [email protected: lesmik...@gmail.com]


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3) Les Mikesell Re: [CentOS] any ima ge software suggestion
| +1 vote
You can boot about any Linux live or install CD that lets you get to the shell (with a Centos...
CentOS
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adrian kok wrote:
> Hi
>
> I am trying to clone harddrive
>
> eg: centos, freebsd, openbsd.....
>
> any ima ge software suggestion for different os

You can boot about any Linux live or install CD that lets you get to the
shell (with a Centos install disk, enter 'linux rescue' at the boot
prompt) and use dd to copy the raw disk devices:
dd if=/dev/sda of=/dev/sdb bs=1M
Be sure you understand the device names for each disk. Using 'fdisk -l'
to see  the existing partition layout might help with that.

However, this is a slow process because the entire disk will be copied,
whether it is used or not.  If you are going to do it often, clonezilla 
is much faster because it knows enough about most linux and windows
filesystems to only copy the used part of the disk and can store
compressed image copies on a local or network disk.  The clonezilla-live 
version is a bootable CD (or USB image).  For larger scale cloning you 
can install the full version with DRBL for network booting into the
clone process. http://clonezilla.org/clonezilla-live/

--
   Les Mikesell
    [email protected: lesmik...@gmail.com]
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4) Les Mikesell Re: [CentOS] SYD flood dropped on Sendmail (centos 4.x)
| +1 vote
If you have a popular server you can get what appear to be syn floods from broken asymmetrical...
CentOS
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Kai Schaetzl wrote:
> Chris Heiner wrote on Thu, 20 Nov 2008 08:48:50 -0800:
>
>> My firewall seems to block an attack my Centos / Sendmail boxes on port 110.
>
> port 110 is your POP server, probably dovecot.
>
>> These servers require a reboot after each attack.
>
> Because of what?
>
>> My firewall says it's
>> blocked?
>
> I don't see this statement in your logs. How/where does it say this?
>
>> Do I need to patch something on sendmail? Or is my firewall not
>> doing its job (Sonicwall)? This is not the first time this has happened.
>
> SYN floods are not unusual, even if it is not an attack.
> What or if you want to do something depends on your situation.

If you have a popular server you can get what appear to be syn floods
from broken asymmetrical routing or bad firewall settings that permit
what would ordinarily be a normal number of client connection requests
to reach you but keep your response from getting back.  So the clients 
sit and retry, hammering you with syn's.

--
   Les Mikesell
    [email protected: lesmik...@gmail.com]

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5) Les Mikesell Re: [CentOS] how to debug hardware lockups?
| +1 vote
Yeah, but those don't stop when you replace the faulty RAM... Mine did, but the errors committed to...
CentOS
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nate wrote:
> Les Mikesell wrote:
>
>> Yes, apparently RAM errors can be subtle and only appear when certain
>> adjacent bit patterns are stored - or when the moon is in a certain
>> phase or something.
>
> Don't forget cosmic rays
>
> http://adsabs.harvard.edu/abs/1978ITNS...25.1166P

Yeah, but those don't stop when you replace the faulty RAM...  Mine did, 
but the errors committed to disk kept randomly re-appearing mysteriously
as the reads from the RAID1 alternated afterwards.

--
   Les Mikesell
     [email protected: lesmik...@gmail.com]

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6) Les Mikesell Re: [CentOS] how to debug hardware lockups?
| +1 vote
Yes, apparently RAM errors can be subtle and only appear when certain adjacent bit patterns are...
CentOS
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Rudi Ahlers wrote:
>> I had machine that would crash about once every week or two in normal
>> operation. Memtest86+ found an error in the 2nd day of running. The worst
>> part was that it left the raid mirrors in a strange state that caused
>> occasional problems for months even after replacing the RAM.
>>
>> --
>
> Did you leave memtest86+ running for 2 days? I thought 1 or 2 cycles
> would be good enough?
>
> I'm hoping to pick-up the server in the next 2 hours then I can see
> what happens when I run memtest86+ or other tests

Yes, apparently RAM errors can be subtle and only appear when certain
adjacent bit patterns are stored - or when the moon is in a certain
phase or something.

--
   Les Mikesell
    [email protected: lesmik...@gmail.com]
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7) Les Mikesell Re: [CentOS] how to debug hardware lockups?
| +1 vote
I had machine that would crash about once every week or two in normal operation. Memtest86+ found...
CentOS
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Rudi Ahlers wrote:
> On Sun, Nov 16, 2008 at 1:14 AM, John R Pierce <pierce@hogranch.com> wrote:
>> Rudi Ahlers wrote:
>>> Well, on a standard CentOS 5.2, /var/log/messages will be the the
>>> place to log problems like this, or where else can I get more info?
>>>
>> tough to write to the disk when the kernel is crashing. ditto the network.
>> that leaves VGAs and serial ports, which can be written to by self
>> contained emergency-crash routines...
>>
>> IIRC, you said this was a Q9something quad core... thats a desktop
>> processor... does this server have ECC memory? (I ask, because few desktop
>> platforms do, while ECC is fairly standard on servers). Without ECC, the
>> system has no way of knowing it read in bad data from the ram, and if the
>> bad data happens to be code and that code happens to be in the kernel,
>> ka-RASH, without any detection or warning, it leaps off into never-land, and
>> you get a kernel fault, almost always resulting in...
>>
>>   kernel panic
>>   system halted
>>
>> with no additional useful information available. with ECC memory, single
>> bit errors get corrected on the fly, and log an ECC error event, while
>> double bit errors result in a system halt with a message indicating such.
>>
>>
>
>
> No, the motherboard doesn't support ECC RAM. The motherboard is a
> Intel DG35EC - http://www.intel.com/products/desktop/motherboards/DG35EC/DG35EC-overview.htm

I had machine that would crash about once every week or two in normal
operation. Memtest86+ found an error in the 2nd day of running.  The 
worst part was that it left the raid mirrors in a strange state that
caused occasional problems for months even after replacing the RAM.

--
   Les Mikesell
     [email protected: lesmik...@gmail.com]

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8) Les Mikesell Re: [CentOS] re: HA Storage
| +1 vote
Yeah - that'll come right after Hell freezes over.
CentOS
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Stephen Harris wrote:
>
>
> Things have changed, but I don't want to rebuild now. If I ever get
> a new (better, stronger, faster) machine then I'll look into it again,
> but then maybe ZFS on Linux will be a strong contender by that point :-)

Yeah - that'll come right after Hell freezes over.

--
   Les Mikesell
    [email protected: lesmik...@gmail.com]



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9) Les Mikesell Re: [CentOS] Appliance platform
| +1 vote
The netflix box is new hardware - and there doesn't seem to be much reason for promotional pricing....
CentOS
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Ted Miller wrote:
> Les Mikesell wrote:
>> Ted Miller wrote:
>>>
>>> Application (in case anyone cares): Move better-than-FM quality audio
>>> across a leased audio circuit with delay under 10 seconds. No
>>> Internet exposure. Obviously one box is required at each end, and
>>> the encoding box works much harder than the decoding box. Software
>>> to run will probably be Ices -> Icecast -> network -> mplayer. Will
>>> be using USB audio interfaces, probably something like the M-Audio
>>> Fast Track Pro. Because of the nature of the application, once it is
>>> booted up the only disk activity is occasional logging when there is
>>> a problem with the connection.
>>>
>>> Any advice, web links, battle scars, or advice gladly accepted.
>>
>> Not quite a match, but maybe worth investigating the hackability: the
>> $99 Roku box sold initially to stream Netflix but supposed to be
>> getting other capabilities. Or for just audio, their soundbridge
>> products that are more expensive but some include speakers.
>> Development specs are available for the soundbridge along with source
>> for gpl'd code included with the netflix box. Not sure about
>> development on the netflix box, though. Might be worth $99 just to
>> take it apart and see what's in there.
>
> This would be more interesting for the playback end (no audio input
> capability is visible) if this were a one-time project, but we will
> probably have to supply more pairs in the future, so a more stable
> platform is more interesting. Price is certainly right, but unlikely to
> hold, as they are charging $200 for their SoundBridge.

The netflix box is new hardware - and there doesn't seem to be much
reason for promotional pricing.  They claim that they will release an 
SDK soon for anyone who wants to generate their own channel (but not
opensource the box itself).  But as long as you can send some 
standard-protocol stream, why worry about matching the hardware?  A sip 
speakerphone might even work as an endpoint.

Here's an interview with the roku CEO:
http://www.youtube.com/watch?v=7z3zUCiELcI

The chumby is probably more hackable, but it already plays network streams.

--
   Les Mikesell
    [email protected: lesmik...@gmail.com]





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10) Les Mikesell Re: [CentOS] Appliance platform
| +1 vote
Or this: perhaps a little too cutesy, but... http://www.chumby.com/
CentOS
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Les Mikesell wrote:
> Ted Miller wrote:
>>
>> Application (in case anyone cares): Move better-than-FM quality audio
>> across a leased audio circuit with delay under 10 seconds. No
>> Internet exposure. Obviously one box is required at each end, and the
>> encoding box works much harder than the decoding box. Software to run
>> will probably be Ices -> Icecast -> network -> mplayer. Will be using
>> USB audio interfaces, probably something like the M-Audio Fast Track
>> Pro. Because of the nature of the application, once it is booted up
>> the only disk activity is occasional logging when there is a problem
>> with the connection.
>>
>> Any advice, web links, battle scars, or advice gladly accepted.
>
> Not quite a match, but maybe worth investigating the hackability: the
> $99 Roku box sold initially to stream Netflix but supposed to be getting
> other capabilities. Or for just audio, their soundbridge products that
> are more expensive but some include speakers. Development specs are
> available for the soundbridge along with source for gpl'd code included
> with the netflix box. Not sure about development on the netflix box,
> though. Might be worth $99 just to take it apart and see what's in there.
>

Or this: perhaps a little too cutesy, but... http://www.chumby.com/

--
   Les Mikesell
    [email protected: lesmik...@gmail.com]
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11) Les Mikesell Re: [CentOS] Appliance platform
| +1 vote
Not quite a match, but maybe worth investigating the hackability: the $99 Roku box sold initially...
CentOS
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Ted Miller wrote:
>
> Application (in case anyone cares): Move better-than-FM quality audio
> across a leased audio circuit with delay under 10 seconds. No Internet
> exposure. Obviously one box is required at each end, and the encoding
> box works much harder than the decoding box. Software to run will
> probably be Ices -> Icecast -> network -> mplayer. Will be using USB
> audio interfaces, probably something like the M-Audio Fast Track Pro.
> Because of the nature of the application, once it is booted up the only
> disk activity is occasional logging when there is a problem with the
> connection.
>
> Any advice, web links, battle scars, or advice gladly accepted.

Not quite a match, but maybe worth investigating the hackability: the
$99 Roku box sold initially to stream Netflix but supposed to be getting
other capabilities.  Or for just audio, their soundbridge products that 
are more expensive but some include speakers.  Development specs are 
available for the soundbridge along with source for gpl'd code included
with the netflix box.  Not sure about development on the netflix box, 
though.  Might be worth $99 just to take it apart and see what's in there.

--
   Les Mikesell
     [email protected: lesmik...@gmail.com]

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12) Les Mikesell Re: [CentOS] re: HA Storage
| +1 vote
Have you looked at virtualbox (http://www.virtualbox.org/)? I haven't tried it myself but it looks...
CentOS
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Stephen Harris wrote:
> On Sun, Nov 09, 2008 at 08:30:42AM -0800, nate wrote:
>> Stephen Harris wrote:
>>
>>> ZFS is really nice. If VMware was supported on Solaris 86 then I
>>> would have built my own home server with Solaris rather than CentOS.
>>> (Although I'm not using VMware on that machine, at present; merely
>>> UserModeLinux for my protected instances). But CentOS is handling my
>>> 5*1Tbyte RAID5 OK for now :-)
>> You know the inverse is true right? Solaris is supported on
>> VMWare ESX(i). Though SATA disks are not officially supported
>> by the VMFS file system in 3.x.
>
> I wanted Solaris as the Host OS so it could natively manage my disks
> via ZFS. Making it a guest would be pointless. Underneath that I would
> run a couple of smaller Linux instances (eg for internet facing services),
> maybe a Windows instance and so on.

Have you looked at virtualbox (http://www.virtualbox.org/)?
I haven't tried it myself but it looks like a match for vmware and can be
hosted on solaris.

--
   Les Mikesell
    [email protected: lesmik...@gmail.com]


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13) Les Mikesell Re: [CentOS] centralized logs server and also storing the logs on the local server
| +1 vote
If you don't mind being somewhat behind on the central copies, the simple-minded way is to run a...
CentOS