Fixing an Overly Eager chmod in Linux

A while ago, someone asked me how to recover from a mistyped recursive
'chmod' they performed.  Similar to the write-up on an "overeager chown",
they mistyped the path and it executed against the root FS (/).  Ideally,
one would have a backup to recover from, however that wasn't an option

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

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

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

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

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

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

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

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

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:

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

Mounting an SVM Root Disk from CDROM

The following illustrates how to mount a root disk under Solaris Volume
Manager (SVM) control when booted from a CDROM.  Our host details:

        HOST:                   snorkle

Fix a Broken chmod, or How to chmod chmod

So here's the setup.  You've logged into one of your servers to update
permissions on a file only to see this:

        server [0] /bin/chmod +x /opt/somefile

Reassociating a Failed Disk in Veritas

Recently we had a situation wherein Vertias Volume Manager (VxVM)
marked a disk as 'failed' while additionally presenting the disk
available for use though unconfigured.  The weird part was that VxVM
continued to allow use of the volume until the volume was stopped.