Writing a master thesis means protecting years of work. You need to handle three core concerns: preventing data loss from hardware failure or malware, ensuring 24/7 access to your work, and keeping it private until publication. The solution is version control with remote backup. Git provides local history and recovery, while a private remote repository…
When you try to create a filesystem on a disk with mkfs, you may see this error: # mkfs -t ext4 /dev/sdd1 mke2fs 1.42.8 (20-Jun-2013) /dev/sdd1 is apparently in use by the system; will not make a filesystem here! Even though the device isn’t mounted, mkfs refuses to proceed. This safety mechanism prevents accidental data…
When you connect an external hard drive with LVM volumes to a RHEL, CentOS, or Rocky Linux system, the logical volumes don’t automatically appear in /dev. Unlike some distributions that handle this automatically, you need to manually activate them using vgchange. Activating LVM Volumes First, plug in your external drive. Then activate all logical volumes…
When you need to completely wipe a USB drive on Windows, you have several reliable options. Choose based on your security requirements: Disk Management for quick reformatting, DiskPart for automation, or secure erasure tools if the drive contained sensitive data. Using Windows Disk Management The simplest built-in approach: Connect the USB drive Open Disk Management…
You have an LVM physical volume (PV) you need to remove from a volume group (VG), but the data needs to be preserved and moved to other available PVs. This is a straightforward but important operation that requires careful execution. Prerequisites Before starting, verify: The VG has sufficient free space on remaining PVs to accommodate…
When a program appends data to a file, you need to know how much space remains on the partition containing that file. This determines whether the file can grow or if you’re about to hit a capacity limit. Quick answer To find available space for a file, use df: df -B1 /mnt/logs/app-log.log | tail -1…
When a disk fails on a server with multiple drives, you need to identify which physical SATA port it’s connected to. Linux device names (sda, sdb, etc.) don’t necessarily map to SATA port order, especially after disk failures or in systems with mixed storage. Using lsblk with Device Paths The lsblk command provides a quick…
GPT (GUID Partition Table) is required for disks larger than 2TB. The older MBR format maxes out at 2.2TB due to 32-bit sector addressing. Tools like fdisk will refuse to work properly with large drives and recommend switching to GPT. While parted has a steeper learning curve than some alternatives, it’s the standard for GPT…
RAID0 (striping) on enterprise RAID controllers like Broadcom MegaRAID is used to expose multiple disks as a single logical volume with no redundancy. This configuration is appropriate only for performance-critical workloads where data loss from a single disk failure is acceptable, or for temporary/cache storage. This guide covers the full setup process on servers with…
A failed BIOS flash can leave your HP Compaq laptop completely unresponsive — white screen, no boot, just LED blinking. Before declaring it dead, try HP’s built-in crisis recovery mechanism. This procedure has recovered many laptops that appeared permanently bricked. The process works even when CMOS corruption prevents normal startup. You’ll need a USB flash…
Use fdisk or parted to create a new partition. parted is generally preferred for modern systems as it handles larger disks better: # parted /dev/sdd (parted) mklabel gpt (parted) mkpart primary 0% 100% (parted) quit Or with fdisk for MBR-based systems: # fdisk /dev/sdd Then: Press n to create a new partition Press p for…
This post describes Xen DomU setup procedures from the early 2010s. While Xen remains critical infrastructure for cloud providers like AWS EC2 and Citrix Hypervisor, it’s rarely deployed for new on-premises virtualization projects. For modern Linux virtualization, consider: KVM/QEMU: The default hypervisor in most Linux distributions, better community support, and tighter kernel integration Proxmox VE…
LVM (Logical Volume Manager) lets you combine multiple physical disks into flexible storage pools. This guide covers creating a volume group from multiple disk partitions—a common setup for servers that need flexible storage allocation across Xen guests, databases, or other demanding workloads. Prerequisites This assumes you have two or more unformatted disk devices available. In…
LVM snapshots provide a fast, efficient way to duplicate virtual machines across servers. This technique applies to any LVM-backed hypervisor including Xen, KVM, and Proxmox. The process uses LVM snapshots on the source server, then transfers the snapshot image to the destination using standard Unix tools. Scenario Source server: 10.0.0.10 with VM stored in /dev/vg_xen/vm-10.0.0.123…
This post covers Xen virtualization benchmarks from 2013. While Xen remains in production use (AWS EC2, Citrix Hypervisor), KVM has become the default hypervisor for most Linux distributions. For current production environments, evaluate KVM with libvirt, direct container solutions (Docker, Kubernetes), or cloud-native platforms. This post is preserved for historical reference and understanding legacy Xen…
A Fedora Live USB lets you boot directly into a Fedora environment without modifying your hard drive. You can use it to test Fedora, troubleshoot your system, or perform a fresh installation. This guide covers modern tools and workflows for creating bootable USB media. Back up any data on your USB stick first — the…
rsync is a reliable choice for backing up your Linux home directory, especially when dealing with large files and incremental changes. Unlike git (which struggles with files >5GB), rsync efficiently handles large files and only transfers what’s changed on subsequent runs. Basic Backup Command The fundamental syntax is straightforward: rsync -avxP \ /path/to/directory/to/backup \ /path/to/directory/for/storing/backup…
Xen remains in production use (AWS EC2, Citrix Hypervisor), though KVM has become the standard Linux hypervisor. This guide covers automating backups for file-backed Xen virtual machines. The approach adapts to other hypervisors like KVM with minimal modification. Architecture and Prerequisites The backup system assumes: Virtual machines stored in /lhome/xen/ with individual directories per VM…