≡ Menu

Disk Storage & RAID Management Tutorials

Questions and answers about SSD (solid state drive), RAID, hard disks’ performance, issues, tips, and software on Linux, RHEL, Fedora, Ubuntu, FreeBSD, AIX, HP-UX, FreeBSD, OpenBSD, OS X and Unix like operating systems ( rss feed ).

How To Create Disk Image on Mac OS X With dd Command

How do I create or write to images to disk on Apple Mac OS X Unix operating system with dd command?
[click to continue…]

Linux WARNING: Duplicate VG name server1 LVM2 Error and Solution

I recently added SSD to my home server and reloaded the operating system. However, when I try to access my dm-crypt based old disk, I am getting the following error:

Reading all physical volumes. This may take a while...
WARNING: Duplicate VG name server01: Existing bc7YA8-eEXt-1aA1-OHTr-zJkA-ucd0-DsbRTc (created here) takes precedence over RIKiar-w3MG-Gzh5-VFWq-bkRT-9IFc-ia8k87
WARNING: Duplicate VG name server01: Existing bc7YA8-eEXt-1aA1-OHTr-zJkA-ucd0-DsbRTc (created here) takes precedence over RIKiar-w3MG-Gzh5-VFWq-bkRT-9IFc-ia8k87
Found volume group "server01" using metadata type lvm2
Found volume group "server01" using metadata type lvm2

The problem is my volume group. I set to to server01 on both old and new hard disk. How can I rename old LVM2? How do I access my old hard disk?
[click to continue…]

Linux / UNIX: Smartctl Check Hard Disk Behind 3Ware RAID Card

I've CentOS Linux and FreeBSD based server running using 3Ware (9650SE-2LP) RAID card. I know how to check hard disk behind Adaptec raid controllers, but how do I look at ATA / SATA disks behind 3ware SCSI RAID controllers using smartctl command?
[click to continue…]

Maximum Number of Disks In RAID 5

Is there a limit to how many drives you can have in one RAID-5? What is the maximum number of physical drives recommended in a RAID-5 set?
[click to continue…]

Linux: Use smartctl To Check Disk Behind Adaptec RAID Controllers

I can use the "smartctl -d ata -a /dev/sdb" command to read hard disk health status directly connected to my system. But, how do I read smartctl command to check SAS or SCSI disk behind Adaptec RAID controller from the shell prompt on Linux operating system?
[click to continue…]

CentOS / Redhat: Create Software RAID 1 Array

Recently, I've added another 73GB SAS disk to my Linux server after the installation. I've 30GB empty partition on old hard disk. How do I convert old /dev/sda3 and new /dev/sdb1 (both 30GB) into RAID 1 to improve NFS server speed and reliability?
[click to continue…]

Linux Create A Bootable USB Pen

How do I create a bootable USB pen drive to start my CentOS / Fedora Linux? How do I create a bootable USB flash pen for installation of Linux, and for creation of rescue and other special-purpose boot disks using command line options?
[click to continue…]

Linux Create Software RAID 1 (Mirror) Array

How do I create Software RAID 1 arrays on Linux systems without using GUI tools or installer options? How do I setup RAID 1 array under Linux systems?
[click to continue…]

Redhat / CentOS Install Memcached Caching System

How do I install memcached a high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load under CentOS / RHEL / Fedora / Redhat Linux?
[click to continue…]

Samba Restrict File Sharing To Particular Users or Network Addresses

All my local Linux user accounts will be able to log in to my Samba server and access share. How do I restrict access to particular users or network subnet such as 192.168.2.1/24?
[click to continue…]