28 December 2011

updated utility, getldp.pl v0.1.7

An updated version of 'getldp.pl', v0.1.7, is now available on the Tools
page.  This update adds handling (long overdue) for reaping any child
processes getldp.pl might spawn while listening for CDP / LLDP packets.
Previously, if getldp.pl timed out and exited while waiting on data,

11 December 2011

Manual P2V with Linux

We recently had a situation wherein we were replacing a physical host
with a virtual machine (VM) instance.  Rather than simply install a
new VM and reapply software packages and configuration, the need was to
retain the existing installation.  To do so, we effectively cloned the

10 December 2011

updated utility, getldp.pl v0.1.6

An updated version of 'getldp.pl', v0.1.6, is now available on the
Tools page.  This version adds details of the sending host including
OS version (CDP only), device capabilities, and management address
(assuming those fields are in the CDP / LLDP packets):

05 December 2011

NIC Replacement in Linux

In the past, I've found it slightly annoying that if I needed to swap
out a network interface card (NIC), Red Hat distros of Linux would kindly
backup the interface configuration for that interface and generate a stub
DHCP configuration in its place.  This leaves the host potentially with

03 December 2011

Fixing a Broken initrd in Linux

I recently had a situation where a host's disk controller failed.
The box would get partially through a BIOS post before throwing errors
about the failed controller and then fail to boot.  To resolve the
situation, we effectively replaced said controller.  This, however, lead

31 October 2011

Fixing an Overly Eager chown in Linux

A while ago, someone asked me how to recover from a mistyped recursive
'chown' they performed.  They mistyped the path and it executed against
the root FS (/), though they caught it before it acted on everything.
Ideally, one would have a backup to recover from, however that wasn't

27 September 2011

VxVM DG Disabled

During a recent SAN maintenance, we ran into an issue on a few hosts that
were unfortunately single pathed to the SAN and lost connectivity to it.
The SAN-presented disk devices were under Veritas Volume Manager (VxVM)
control which started to present I/O errors as a result and displayed

01 August 2011

Configuring iSCSI Initiators in Windows 2008

Since it's been a while since I've written up a Windows related post, I
thought I'd add one on setting up iSCSI initiators from the command line
(cli).  (It also gave me a reason to toy around in PowerShell (PS).)
Microsoft makes iSCSI initiator software available for Windows 2000,

24 July 2011

Process Memory Usage

Since resources on a host are finite, it can be useful to know the
impact of a process or processes on those resources.  In this instance,
we'll take a look at a process' use of memory.  Our details for this are:

13 July 2011

Notes on Packages in Solaris 11

While working out details for a separate write up, I started stumbling
through Solaris' new handling of packages, IPS.  Unlike previous versions
of Solaris which used the traditional "pkgXYZ" commands, directory
structures, etc, IPS (image packaging system) uses a completely new

06 July 2011

VLAN Tagging and Vanity Naming in Solaris 11

While awaiting Solaris 11 to be released, I've recently been poking
around in Solaris 11 Express for a preview of what to expect.  In setting
up a test box, I needed to set up VLAN tagging (802.1q trunking) on
an interface.  Due to some of the new Solaris 11 networking features,

18 June 2011

Configuring iSCSI Initiators in Linux

In part 1, we worked through how to set up iSCSI targets in Linux
(the server side).  Here, in part 2, are my notes on how to set up the
initiators in Linux (the client side).  Our host details for this are
the same as part 1:

15 June 2011

Configuring iSCSI Targets in Linux

Since I've already been looking into iSCSI on Solaris, I thought I'd look
to see what Linux has to offer.  While in comparison to Solaris I think
the Linux side could still mature a little, it still has potential and
a functional offering.  The following is part 1 of my notes detailing

13 June 2011

Configuring iSCSI Initiators in Solaris

In part 1, we worked through how to set up iSCSI targets in Solaris
(the server side).  Now, for part 2, I present my notes on how to set
up the initiators in Solaris on the client side.  Our host details for
this are the same as part 1:

08 June 2011

Configuring iSCSI Targets in Solaris

While reviewing potential ideas for several environments, I started
looking into the use iSCSI as a means of providing remote storage.
With that in mind, this is part 1 of my iSCSI notes, detailing the
configuration of a test Solaris iSCSI target node which would provide

26 May 2011

Replicating a ZFS FS Between Hosts

Occasionally, it can be useful to fully replicate a volume of data from
one host to another.  Perhaps you need to mirror a production filesystem
(FS) for use in development, need a sane backup, etc.  The following
describes one way of doing this using ZFS.  Additionally, we're going

19 May 2011

Replacing a Failed SVM Disk

At some point, everyone deal's with a disk failure, as I had to do
recently.  In this case, it was a root disk.  Thankfully, however,
it was mirrored with SVM (Solaris Volume Manager).  Unfortunately, disk
failures aren't the type of thing that should happen too frequently so

17 May 2011

Sending Messages to Users

Recently while working on a problem with someone else, I needed to have
them run a series of commands with specific options.  Since we were
both working remotely, it wasn't as simple as telling them to look
over my shoulder.  Though I tried telling them the commands over the

16 April 2011

Enabling Local FS Quotas in Linux

Quotas allow you to limit the amount of space a user or group can use
and / or the number of files a user or group can create on a filesystem
(FS).  The following shows how to set up these quotas and the expected
user experience.  Our host details for this are:

07 April 2011

Granting Elevated Privileges in Solaris

root, root, root, everybody always wants root.  Developers, application
administrators, users, they all seem to find a reason to "need" root
access.  Since normally these needs are for access to particular files
or to perform very specific tasks, only a subset of root's access is

27 March 2011

Finding Open Files in Linux

Finding open files in Linux is quite similar to finding them in FreeBSD
and Solaris.  Here, we'll specifically identify open files on a particular
filesystem (FS) within a Linux environment.  Our host details this
time are:

25 March 2011

Finding Open Files in FreeBSD

Following up the same in Solaris, here's how to identify open files on
a particular filesystem (FS) in a FreeBSD environment.  Our host details
for this are:

23 March 2011

Finding Open Files in Solaris

During a recent discussion, another sysadmin asked that I write him a
tool to identify any open files on a particular file system (FS) in a
Solaris environment.  Rather than reinvent the wheel, I provided him
with the steps outlined here.  Our host details are:

17 March 2011

updated utility, getldp.pl

An updated version of 'getldp.pl', v0.1.5, is now available on the
Tools page.  This version now appropriately handles VLAN tagged (802.1q)
CDP packets and includes output for duplex, 802.1q priority, and VLAN ID
(assuming the fields are present in the CDP packets):

15 March 2011

Converting inet_aton and inet_ntoa

At some point or another, you've probably stumbled upon the 'inet_aton'
and 'inet_ntoa' functions.  Perhaps you have used them in programming,
or maybe for a MySQL statement, etc.  Briefly, for those not familiar
with either function, 'inet_aton' takes an IP address (10.234.18.76) and

03 March 2011

Configuring NFS in FreeBSD

Having written up Solaris and Linux, it's time to take a look at
configuring NFS in FreeBSD.  Briefly, NFS (network file system) provides
access to remote filesystems which appear similar to local resources
on client hosts.  The following focuses on simple NFS server and client

28 February 2011

Configuring NFS in Linux

As a follow up to 'Configuring NFS in Solaris', we turn to the same
in Linux.  Briefly, NFS (network file system) provides access to remote
filesystems which appear similar to local resources on client hosts.
The following focuses on simple NFS server and client configuration in

24 February 2011

File Integrity Checks via Package DB

After a system has been installed, files tend to change over time.
These changes may be deliberate, part of normal host operation, the
result of an errant 'chmod', etc.  Tools like Samhain, AIDE, and Tripwire
(note 0) have been devised specifically to identify such changes which

20 February 2011

Configuring NFS in Solaris

Networked environments allow for the sharing of many resources, including
filesystems (FS).  As a long time industry standard in UNIX, NFS (network
file system) provides access to remote filesystems which appear similar
to local resources on client hosts.  Since Sun Microsystems originally

17 February 2011

Network Ports and Processes (Windows)

Previously, I wrote up how to match open network ports to running
processes
for FreeBSD, Solaris, and Linux.  If UNIX hosts can correlate
ports to processes, shouldn't Windows Server be able to as well?
Beginning with Windows 2000, it can.  Our host details for this are:

13 February 2011

new utility, basecon.pl

I've posted a new utility, basecon.pl, to the Tools page.  basecon.pl is a simple utility that converts base inputs to selected base output.  Currently, basecon.pl can accept input and output types of ascii, binary, decimal, hexadecimal, and octal.  The following is sample output from basecon.pl:
user@host [0] basecon.pl -h

03 February 2011

Static Routes in Linux

Nearly every UNIX sysadmin at some point will need to know how to manage
a host's routing table.  With that in mind, here's how to manage static
routes on a Red Hat Linux clone.  Our details for this are:

31 January 2011

Static Routes in FreeBSD

A friend of mine recently told me that while he appreciated the detail
and content of my writings, a good deal of the subject matter was a
little beyond him.  In support of the fresh-faced sysadmins and those
that might be new to FreeBSD (we were all there once), this write up is

29 January 2011

Breaking and Syncing an MD Root Mirror

Here's one of those times where I thought, "I wonder", as in I wonder if
I can break an MD root mirror and sanely recreate it.  You can do so with
other software RAID solutions so why not here?  Well, you can.  There is
nothing short about this procedure, taking 80+ commands to accomplish.

23 January 2011

Creating an MD Root Mirror in Linux

For whatever reason, you originally set up your Linux host without a root
disk mirror and now you want it mirrored.  One could say "just re-install,"
but surely there is another way, and there is.  The solution isn't quick
or simple, though it isn't impossible.  Our host details are:

20 January 2011

Missing Linux inittab

Since I'm somewhat on a "break the boot process" kick, I've deliberately
removed '/etc/inittab' on a Linux host.  As the following illustrates,
a missing 'inittab' really isn't as bad as it seems.  Our details for
this setup are:

17 January 2011

Missing GRUB Config in Linux

Having recently written up how to restore GRUB to a missing / corrupted
master boot record (MBR)
, it seemed appropriate to follow up with
resolving a missing GRUB config file.  Our host details for this
situation are:

15 January 2011

Recreate a Linux EXT3 FS

We've looked at Solaris and FreeBSD, now it's time to look at recreating
a Linux EXT3 filesystem.  Similar to the previous two, if you customized
the options to 'mke2fs / mkfs', 'mke2fs -n' is not the answer since it
will only produce data about generic FS creation.  Our host details this

13 January 2011

Recreate a FreeBSD UFS FS

As a follow up to recreating a Solaris UFS FS, the following details
FreeBSD.  Just as with Solaris, when trying to determine how a filesystem
was created, 'newfs -N /dev/da2s1a' is not the answer, as it only produces
information relevant to a default FS creation.  Our host details for this

11 January 2011

Recreate a Solaris UFS FS

Have you ever wondered what options were used to create a UFS filesystem
(FS) on a Solaris host?  Normally when you ask that question, it
seems someone will refer you to passing '-N' to 'newfs'.  Unfortunately,
this response will only provide you with default parameters to build a

10 January 2011

Disk Cloning in Linux

A while back, I wrote up how to clone a disk in Solaris and in FreeBSD,
yet somehow managed to overlook writing up how to do so in Linux.
This write up is to rectify just that, how to clone a disk, in this case,
the root disk, in Linux.  The following are our setup details:

08 January 2011

GRUB, a Corrupted MBR, and Linux

Recently, after cloning a root disk in Linux, I ran into an issue because
I failed to setup the master boot record (MBR) on the alternate disk.
Everything else was configured, including the boot image files and grub
configuration under /boot/grub, but the MBR wasn't setup.  The following

07 January 2011

Adding Swap Space in Linux

We've discussed FreeBSD and Solaris, now it's time to have a look at
adding swap space in Linux.  As previously handled, the setting up
of swap on a free disk partition or else a swap file is discussed.
The following details our example host:

06 January 2011

Adding Swap Space in Solaris

Following up on "Adding Swap Space in FreeBSD", we take a look at the same
with Solaris.  As in the FreeBSD writeup, the usage of a free disk slice
or else a swap file is discussed.  The following details our host info:

05 January 2011

Adding Swap Space in FreeBSD

While it shouldn't occur too frequently, it is likely at some point as a
sysadmin, you will need to add additional swap space to a box.  At that
time, your options will be to use a free disk partition with suitable
space or to create a swapfile on an existing filesystem.  The following

01 January 2011

Mounting ISO Images

So you've created a fresh ISO image and now you want to use it, verify
its contents, etc.  Whatever your purpose, it is fairly trivial to
mount the image file and access it.  The following are our host details: