Abusive IP ranges blacklist

Make sure this makes sense for you but I've started to block a lot of commercial Cloud services and easily accessible providers as they are a very high source of abusive traffic. The cost savings for a lot of organizations are huge, as you now have less bandwidth usage and less resource usage from garbage/bot/malicious traffic. This mainly works for when you can be reasonably sure that your audience has no business visiting your service(s) from freely accessible commercial IP ........

efibootmgr: option requires an argument -- 'd' efibootmgr version 15 grub-install.real: error: efibootmgr failed to register the boot entry: Operation not permitted.

This sometimes happens when trying to install the EFIversion of grub to a device when you are booted into Legacy/MBR mode. It doesn't seem to occur on all machines, but some and seems somewhat BIOS dependent. grub-install --target=x86_64-efi /dev/sda Installing for x86_64-efi platform. grub-install.real: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. grub-install.real: warning: Couldn't find physica........

How To Stop DNSMasq from listening on all IPs/Interfaces and allow only localhost

Some people find it less than intuitive to do on DNSMasq and by default DNSMasq is available on 0.0.0.0 which could even be your LAN or Public IP. Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp ........

Docker Swarm vs Kubernetes Comparison Guide

A lot of companies are unsure which solution to choose and many may not be aware of Docker Swarm as an alternative to Kubernetes. One thing that many Sysadmins find is that Docker Swarm is simply easier, quicker to setup and maintain by far than Kubernetes.........

request_module: runaway loop modprobe binfmt-464c Kernel panic - not syncing: No init found Pid: 1, comm: swapper/0 Not tainted solution

request_module: runaway loop modprobe binfmt-464c Kernel panic - not syncing: No init found Pid: 1, comm: swapper/0 Not tainted This is usually caused by a mismatch in architecture and happens frequently in development environments. Here is a example of what caused this issue: Your binaries are based on one architecture Your kernel was compiled with another architecture. Why does this happe........

Debian Ubuntu apt install stop daemon questions/accept the default action without prompting

This can be a real pain when automating things and you do an apt install and some packages ask a lot of questions. Make sure you set this variable when running: DEBIAN_FRONTEND=noninteractive Remember as well that if chrooting you will want to run like this: DEBIAN_FRONTEND=noninteractive apt install -y yourpackagename ........

Cisco UC CME How To Enable Licensed Features

Router#show license Index 1 Feature: ipbasek9 Period left: Life time License Type: Permanent License State: Active, In Use License Count: Non-Counted Lic........

md mdadm array inactive how to start and activate the RAID array

cat /proc/mdstat Personalities : [raid1] [raid10] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] md124 : inactive sdj1[0](S) 1048512 blocks Solution, we "run" the array sudo mdadm --manage /dev/md124 --run mdadm: started array /dev/md/0_0........

Loaded: masked (Reason: Unit hostapd.service is masked.) Solution in Linux Debian Mint Ubuntu

If you are getting this error from systemctl "Loaded: masked (Reason: Unit hostapd.service is masked.)" we need to unmask the service. Solution systemctl unmask hostapd Removed /etc/systemd/system/hostapd.service. It's fixed root@routerOS:/var/log# systemctl start hostapd root@routerOS:/var/log# systemctl status hostapd ● hostapd.service - Access point and authentication server for Wi-Fi and Ethern........

How To Do Linux Network Bonding Teaming in Mint Debian Ubuntu

Bonding is an excellent way to get both increased redundancy and throughput. It is similar to the "Network Teaming" feature in Windows. There are a few different modes but we will use mode 6, I think it's the best of both worlds, as it is not just a failover, but it provides round robin, so you will get redundancy and load balancing. So if you have a 1G single port, you will have a combined throughput of 4G at this point. Just bear in mind that the true thr........

Docker Tutorial HowTo Install Docker, Use and Create Docker Container Images Clustering Swarm Mode Monitoring Service Hosting Provider

The Best Docker Tutorial for Beginners We quickly explain the basic Docker concepts and show you how to do the most common tasks from starting your first container, to making custom images, a Docker Swarm Cluster Tutorial, docker compose and Docker buildfiles.........

HongKong VPS Server, Cloud, Dedicated Server, Co-Location, Datacenter The Best Guide on Hong Kong, China Internet IT/Computing

In our 2024 VPS Server/Cloud Buyer's Guide, we place the location of your VPS/hosting/server as one of the priorities that is often overlooked. 2024 Update - Datacent........

Juniper JunOS Command Overview and Howtos Switch, Router, Firewall Tutorial Guide

Enable "cli" mode equivalent in JunOS cli Configure Mode configure So rather than going to the console on a Cisco switch and typing "enable" and then "conf t", the equivalent in JunOS is "cli" and "configure". How Do You Apply Changes You've Made? You can make all kinds of changes to the switch, but remember they are not........

Scanner not working in Linux Ubuntu Fedora Mint Debian over the network? Use sane-airscan!

I have a Canon MF642c and the scanner wouldn't work. I tried to use saned but it didn't work with the BJNPlike it did for some other Canon models. Introducing sane-airscan with packages for the most common distributions: https://software.opensuse.org/download.html?project=home%3Apzz&package=sane-airscan http........

mdadm how to stop a check

Is a mdadm check on your trusty software RAID array happening at the worst time and slowing down your server or NAS? cat /proc/mdstat Personalities : [raid1] [raid10] md127 : active raid10 sdb4[0] sda4[1] 897500672 blocks super 1.2 2 near-copies [2/2] [UU] [==========>..........] check = 50.4% (452485504/897500672) finish=15500.3min speed=478K/sec ........

How To Get Started on Ubuntu with gpt-2 OpenAI Text Prediction

apt install software-properties-common add-apt-repository ppa:deadsnakes/ppa apt update apt install python3-pip apt install python3.7 curl gnupg python3.7-dev git ln -s /usr/bin/python3.7 /usr/bin/python3 pip3 install numpy keras_preprocessing curl https://bazel.build/bazel-release.pub.gpg | sudo apt-key add - echo "deb [arch=amd64] http://storage.googleapis.com/bazel-apt stable jdk1.8" | sudo tee /etc/apt/sources.list.d/bazel........

ssh Received disconnect from port 22:2: Too many authentication failures

If you are getting this error it is usually caused by having more than 5 keys in your ".ssh" directory. It is a bit of a bug and this is how it manifests itself. You will find at this point that you are not given any chance to enter a password, or if you are using key based auth that the same thing happens. You'll also find that this is happening with ALLservers you try connecting to. The solution is to move away key pairs from .ssh so that there ar........

OpenVZ vs LXC DIR mode poor security in LXC

It is unfortunate that LXC's dir mode is completely insecure and allows way too much information from the host to be seen. I wonder if there will eventually be a way to break into the host filesystem or other container's storage? OpenVZ better security: [root@ev ~]# cat /proc/mdstat cat: /proc/mdstat: No such file or directory /dev/simfs 843G 740G 61G........

how to use ifplugd in Linux to execute a command or script when a NIC cable is unplugged or plugged in

It is fairly simple to use once you know how to use it. However, the tricky thing is that by default it doesn't seem to be active or listen on any interface on manually specified. How To Install ifplugd First we install ifplugd sudo apt install ifplugd Let's enable it on our desired device(s) vi /etc/default/ifplugd set this line as so:........

Centos 7 Stopped and Disabled Firewalld and ports still blocked

This is a gotcha but be aware sometimes iptables may be active and loaded by default. Also make sure you don't just disable firewalld but also stop it otherwise it will still block stuff: systemctl stop firewalld If the above is not the issue then it is possible iptables is running and blocking stuff too, so you'll need to stop iptables. So in addition to opening firewalld or disabling it, you would need to disable iptables........

Cisco Unified Communications Manager Express Cheatsheet CUCME CME Tutorial Guide

Video Links: How To Setup 2 Phones on a Single CME Router and get the GUI going. How to use Dialpeers with CME with two routers How to implement call restrictions using COR / Class of Restriction Set your clock: HH:MM:SS clock set 22:00:00 24 September 2024........

Linux Ubuntu Debian Missing privilege separation directory: /var/run/sshd

service sshd status ● ssh.service - OpenBSD Secure Shell server Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled) Active: failed (Result: start-limit-hit) since Wed 2019-10-02 11:07:54 EDT; 36s ago Process: 476 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=255) Oct 02 11:07:54 box systemd[1]: Failed to start OpenBSD Secure Shell server. Oct 02 11:07:54 box sys........

Virtualbox vbox not starting

If you've just installed VBox and it is not starting or working, the most common problem is usually that you don't have your kernel source installed, which means there is no kernel driver for vbox so it can't work. You may get an error that says "Kernel driver not installed" in your Virtualbox. So the first thing you should do is install your kernel source by running this: sudo apt-get install linux-headers-`uname -r`........

Cisco Unified Communications Manager / CUCM IP 8.6,10,12 Install Error Solution

Install Errors on Version 12: This error happened on QEMU emulator version 2.11.1 pve-qemu-kvm_2.11.1-5 on Proxmox/Debian but installing on QEMU.12 on Centos 6 did not produce the error. *Update it is not related to the OS or QEMU version. This happened in Centos 6 too after a second install. What really causes this even though you successfully install........

Ubuntu Debian Mint Linux SSHD OpenSSH Server Not Starting After Reboot Solution

If you get error messages like this it is usually because /var/run/sshd does not exist. root@userbox:/# service sshd status ● ssh.service - OpenBSD Secure Shell server Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enab Active: failed (Result: start-limit-hit) since Wed 2019-04-10 02:24:44 EDT; 1 Process: 511 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=255)........

Cisco Unified Communications Manager 12 Install Errors on Proxmox/KVM

The strange thing is that usually the first install or two will work on any new machine but then it suddenly won't. I had this experience on QEMU 2.13 on a different machine. There is something finicky or buggy about the CUCM installer even when choosing the same virtual hardware specs. qemu-kvm command: /usr/libexec/qemu-kvm -version QEMU PC emulator version 0.12.1 (qemu-kvm-0.12.1.2-2.506.el6_10.1), Copyright (c) 2003-2008 Fabrice Bellard ........

Linux How To Disable SATA NCQ For Better Performance

This is the closest way to disabling it without using the "libata.force=noncq" kernel boot option is to set the queue to a depth of 1 which doesn't actually disable it. Change the sdc below to match the device you want to disable NCQ for. [root@officebox ~]# echo "1" > /sys/block/sdc/device/queue_depth Errors that indicate you are having a performance issue are these in messages or dmesg relating to N........

the sign-in method you're trying to use isn't allowed. For more info, contact your network administrator - solution for active directory

This is usually because the Group Policy forbids that user or group from logging in. run "gpmc" (not "gpedit.msc" as that is for local computer settings when you are not using Active Directory) or go to Administrative Tools and Group Policy Management. Edit the default domain policy like below........

How To Use Letsencrypt SSL/TLS Encryption to Create Certificates without installing on the target machine

For some reason, perhaps you don't want to run a daemon or let Letsencrypt have access to your production server. There is a way to use it like a normal CSR/CA setup in manual mode. ./letsencrypt-auto certonly --manual -d realtechtalk.com - www.realtechtalk.com Eventually you will get prompted to create a certain path and file with certain data: Create a file containing just this data: Casdfasfadsfsad........

Cisco Switch Setup Guide Command List

Enter configuration console: enable configure terminal This is important because if your console doesn't look like below none of the commands will work! Switch(config)# Save and Apply Settings wr Show Switch Configuration: show run Show Port List/Sta........

Centos 7 Reallocate logical volume space to another

Do you hate how Centos 7 defaults to allocating most of your valuable space to /home even though it is a production server? Here is a quick guide on how to take back that space live, while online (of course make sure you have backups just in case something goes wrong!): First we will reduce our home dir by 100G: lvreduce -L -100G /dev/mapper/centos-home WARNING: Reducing active and open logical volume to ........

mdadm force resync when resync=PENDING solution

cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] md127 : active (auto-read-only) raid10 sdc1[0] sdb1[2] 1953382400 blocks super 1.2 512K chunks 2 far-copies [2/1] [U_] resync=PENDING bitmap: 15/15 pages [60KB], 65536KB chunk Solution force repai........

Linux wlan0 check all wireless clients

iw dev wlan0 station dump This is very useful because it is helpful if you are running something like hostapd and need to see the signal strength and negotiated connection speed. Station ff:ff:ff:ff:ff:ff (on wlan0) inactive time: 16309 ms rx bytes: 25451 rx packets: 325 tx bytes: 44381 tx packets: 159 tx retries: 0 tx failed: 0 signal: -72 [-72] dBm signal avg: -72 [-72] dBm........

How Does Cisco CUCM (Cisco Unified Communication Manager) Work?

Cisco's CUCM (Cisco Unified Communication Manager) is a system that combines voice, video, data and mobile products into a single unified management suite. At its core, the CUCMis like a "Super PBX" that controls the flow of all communications through an organization even single or multiple site deployments. Cisco's CUCMmakes communication more effective and simple through centralized management and unification of communications resources.........

What DNS Options Does Active Directory Offer in Windows Server 2008,2012,2016 ?

What Is Active Directory? Active Directory is essentially an enhanced, centralized database with a set of objects that make user management, authorization, and data management simpler. Active Directory is synonymous with "Domain Controllers" where a single "domain" often consists of multiple sites and members of the domain. Multiple domains can also be joined to belong to a tree ( a collection of domains). And the highest layer is the forest whi........

systemd management using systemctl and journalctl to check systemd logs

systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system. The key commands or arguments you will use with systemctl are the following: Unit Commands: list-units [PATTERN...] List loaded units &nbs........

Linux Mint 18 Screen Goes Dark or Black After Screensaver or even when using the Desktop Solution

You can search for this bug and it seems like it may be related to ecryptfs and is many years old. The symptoms are that you return to the computer and the screensaver was active or the screen was asleep/black and it doesn't seem to come back. But you check by SSH the computer is running fine and are frustrated you'll lose your running programs and have to reboot. There is a simple solution: Ctrl + Alt + F1 Ctrl +Alt + F8 Ba........

Maximum number of connections from user+IP exceeded (mail_max_userip_connections=10) Dovecot Solution

This happens because Dovecot limits the maximum IMAPconnections per IPto just 10. This may be fine for a single client side IPbut if an entire office or multiple users are behind one IPor a single heavy user is active then you will get bizarre errors in your e-mail clients such as "Password Incorrect" or similar in Thunderbird. It won't be obvious on the client side as to what the problem is and they will probably just think the server is misconfi........

mdadm how to mount inactive array

myguy@devbox:~$ sudo mdadm -As myguy@devbox:~$ cat /proc/mdstat |grep sdf md125 : inactive sdf3[2](S) sudo mdadm --manage /dev/md125 --run mdadm: started /dev/md125 ........

linux cp and mv will not overwrite due to alias!

This through me for a loop when I would do a cp -rf or mv -f nothing would get overwritten even if piping y or yes to the command. Type alias and you'll see why: alias cp='cp -i' alias l.='ls -d .* --color=auto' alias ll='ls -l --color=auto' alias ls='ls --color=auto' alias mv='mv -i' alias rm='rm -i' The -i is a safeguard against messing things up but however does mess things up worse when you know what........

ecryptfs how to mount or recover from a backup

The easiest way to recover or mount an off-line ecryptfs directory is the built-in command from ecryptfs sudo ecryptfs-recover-private It will find your wrapped passphrase and ask for your password and mount it in tmp. Much easier especially when your current active OS is using ecryptfs too. This a fantastic tool when going through old backups.........

cudaminer freezes Linux Mint taints kernel

When running cudaminer once it tries to initialize the card the entire screen freezes. The computer itself is still running but the Xorg is done for, you cannot even switch to another console window and must reboot (even an mdm or Xorg restart does not help). At first cudaminer will give you these errors: stratrum_recv_line failed ...retry after 15 seconds GPU #0: Geforce 210 with compute ca........

What happens when you unplug 1 or more devices from an mdadm RAID array to simulate a failure in Linux Ubuntu/Centos/Debian?

In short the two drives in the array were /dev/sdd and /dev/sde. The kernel sees they were unplugged and have gone down as you can see below. mdadm caught the first one being unplugged /dev/sde and disabled the missing drive. However when the final drive that was part of the array is unplugged it didn't notice at all. Instead it complains about an IO error later for drives that the kernel knows do not exist anymore. [45817.162728] ata4: exception........

mdadm and lvm how to completely disable and remove vg/pv/lv

In short the solution is just to use vgremove for the actual /dev/mapper device: vgremove /dev/mapper/backups-backuplv box mnt # mdadm --manage /dev/md8 --stop mdadm: Cannot get exclusive access to /dev/md8:Perhaps a running process, mounted filesystem or active volume group? box mnt # lv lvchange lvconvert lvcreate l........

mdadm frozen and doesn't realize array is dead/missing failed due to unplugged drives

This was a surprising bug but I unplugged all drives for an array md127. At first it was just 1 drive and mdadm seemed to notice this. I unplugged the second drive taking the array offline but mdadm did not realize it was offline and still showed a non-existent disk as being part of it. This created problems trying to unmount it or even to stop this array with mdadm freezing. As for how to fix it I can only think of making sure you are not in a mounted path of........

Unable to mount location Failed to retrieve share list from server: No such file or directory solution

Cannot even "Browse Network" when clicking on "Windows Network" Unable to mount location Failed to retrieve share list from server: No such file or directory logs: [2017/02/14 00:16:44.271314, 0] ../source3/nmbd/nmbd.c:58(terminate) Got SIGTERM: going down... [2017/02/13 17:35:41.797944, 0] ../lib/util/become_daemon.c:124(daemon_ready) &........

mdadm how to make inactive array active

This happens when you assemble array it doesn't mean it will be active for many reasons: md20 : inactive sdf1[2](S) 732442488 blocks super 1.2 Solution: sudo mdadm --manage /dev/md20 --run........

DRBD Split-brain solution

Uh oh [17925926.174277] block drbd0: Handshake successful: Agreed network protocol version 96 [17925926.174325] block drbd0: conn( WFConnection -> WFReportParams ) [17925926.174342] block drbd0: Starting asender thread (from drbd0_receiver [1682]) [17925926.174432] block drbd0: data-integrity-alg: [17925926.174581] block drbd0: drbd_sync_handshake: [17925926.174586] block drbd0: self 2AAE66AF9252D6DB:2815BF........

mysql_real_escape_string returns an empty string solution

This is a common mistake but many people do not realize this function comes from mysql itself, so therefore you need an active mysql connection open. Usually the string will be empty and null when you call it from outside of the database connection portion of your code. eg. an example of the wrong way and creating a null/empty string $var = mysql_real_escape_string($myself) mysql_connect(); // returns n........

Cannot Read License File cPanel Solution

This can happen because port 80 is not open, or your license has expired and/or your IP is out of date and also if the license server itself from cPanel is having issues. In most cases as long as you have a valid license the following command will solve it: /usr/local/cpanel/cpkeyclt Updating cPanel license...Done. Update succeeded. Building global cache for cpanel...Done Cannot........

Centos installing grub problems suspect gpt problem

grub> root (hd0,0) root (hd0,0) Filesystem type is ext2fs, partition type 0xfd grub> setup (hd0) setup (hd0) But if you do: root (hd1,0) setup (hd1) it does work, I think hd0/sda had a GPT partition that was not removed properly (what I did was just dd bs=512 count=1 the partition table from another drive since the partition table should be identical). Checking if "/boot/grub/........

Centos 6 how to guide convert LVM non-RAID into mdadm 1/10 RAID array live without reinstalling

Here is the scenario you or a client have a remote machine that was installed as a standard/default minimal Centos 6.x machine on a single disk with LVM for whatever reason. Often many people do not know how to install it to a RAID array so it is common to have this problem and why reinstall if you don't need to? In some cases on a remote system you can't easily reinstall without physical or KVM access. So in this case you add a second physical or disk or already ha........

status: { DRDY ERR } error: { ICRC ABRT } failed command: WRITE FPDMA QUEUED MCP55 Linux Errors

[ 2868.041375] ata1: EH in SWNCQ mode,QC:qc_active 0x40 sactive 0x40 [ 2868.041554] ata1: SWNCQ:qc_active 0x40 defer_bits 0x0 last_issue_tag 0x6 [ 2868.041556] dhfis 0x40 dmafis 0x40 sdbfis 0x20 [ 2868.041874] ata1: ATA_REG 0x41 ERR_REG 0x84 [ 2868.042013] ata1: tag : dhfis dmafis sdbfis sactive [ 2868.042163] ata1: tag 0x6: 1 1 0 1 [ 2868.042301] ata1.00: exception Emask 0x1 SAct 0x40 SErr 0x400000 action 0x6 frozen [........

HP Procurve Switch 2824 CLI Telnet Experience , Guide and Tutorial

------------------------------------- ProCurve J4903A Switch 2824 Software revision I.10.77 Copyright (C) 1991-2009 Hewlett-Packard Co. All Rights Reserved. RESTRICTED RIGHTS LEGEND Use, duplication, or disclosure by the Government is subject to restrictions........

/usr/libexec/mysqld: The table 'session' is full solution

First of all if you're getting this error it is a result of extreme database activity. If you aren't expecting it or it doesn't make sense to you 99% of the time this is a database driven script being exploited (some common examples I see often are things like phpBB being hit by dozens, hundreds or thousands of bots making constant DB write requests). The easiest way to identify this is to restart MySQL and then run the third party tool "mtop" and you'll see all........

CPanel Link to all of the command line options

CPanel says you can access 98% of the functions through CLI which experienced Unix/Linux admins prefer for simplicity and for scripting. I've never found CPanel easy to use from the admin panel, it seems everything is hard to find and a simple task becomes a series of hunts. So for people like me here's the list: http://cpanel.net/system-administrators/command-line-scrip........

Asterisk VOIP Sipura/Linksys PAP2T Calls Not Being Received Solution

This problem seemed to happen recently but was likely causing issues before where the phone(s) do not ring. Now there are a few reasons why this can happen especially if your adapter has DND mode enabled (disable it). However that wasn't my issue and Ionly figured it out the other day when by fluke if you're on the phone (making a call) then calls will come in. That's when Ifigured out the solution: This likely app........

What a hdd hard drive and mdadm RAID array failure looks like in Linux

[3805108.257042] sd 0:0:0:0: [sda] 1953525168 512-byte hardware sectors: (1.00 TB/931 GiB) [3805108.257052] sd 0:0:0:0: [sda] Write Protect is off [3805108.257054] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00 [3805108.257066] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [3805108.257083] sd 0:0:0:0: [sda] 1953525168 512-byte hardware sectors: (1.00 TB/931 GiB) [3805108.257090] sd 0:0:0:0: [sda] Write Protect is off........

DD-WRT Set Static DHCP IP Address For Lease

Services -> Services "Static Leases" Fill out an empty line: MAC Address Host Name IP Address Those first 3 fields are mandatory, if you miss it then the changes will be lost even if you try to save. Make sure you've d........

mdadm how to add additional RAID 1 drives

This is a great way to upgrade your RAID array or move it/copy it to a new set of hard drives. Eg. you have a current RAID 1 array on older/slower drives. Just add at least 1 of the new drives to the array, update grub/install it and then boot into it. Then you have a transparent data migration that is fully synchronized. mdadm --grow /dev/md126 --raid-devices 3 md127 : active raid1 sdc1........

Dell Perc 6/i SATA benchmarks without battery

The results are not bad, the Hitachi performs the same as it does in a SATA2 motherboard. However, the 2TB is much different, on a similar 2TB Toshiba I get about 198MB/s on a different motherboard vs the 2TB Hitachi which should produce similar results. This Dell Perc 6/i is on a PCI x8 riser card and is connected to a 12-port backplane. Adapter #0 Enclosure Device ID: 32 Slot Number: 0 Enclosure position: N/A De........

LSI MegaRAID Adventures, Guide and HowTo

LSi Megaraid At first it was configured as a RAID 0, then I deleted the Virtual Disk Group. I thought both drives would be shown and detected in Linux as sda and sdb but it actually shows nothing. To make them work you have to hit Ctrl+R before the system boots (when prompted) and create a Virtual Disk Group. In my case I created each one as RAID 0 (with a single drive only) as I just wanted JBOD but there is no such option or default in these Dell Pe........

mdadm enable bitmap to speed up rebuilds

Have you ever unplugged the wrong drive and then had to rebuild the entire array? It may not be a big deal in some ways but it does make your system vulnerable until the rebuild is done. Many distros often enable the "bitmap" feature and this basically keeps track of what parts need to be resynced in the case of a temporary removal of a drive from the array, this way it only needs to sync what has changed. To enable bitmap to speed up rebuilds and sync........

mdadm create RAID 1 array example

mdadm --create /dev/md2 --level=1 --raid-devices=2 /dev/sda3 /dev/sdb3 cat /proc/mdstat Personalities : [raid1] md2 : active raid1 sdb3[1] sda3[0] 1363020736 blocks super 1.2 [2/2] [UU] [=>...................] resync = 8.3% (113597440/1363020736) finish=276.2min speed=75366K/sec ........

SSH Can't Login/Hang

Client Log OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug1: Connecting to 192.168.1.253 [192.168.1.253] port 22. debug1: Connection established. debug1: permanently_set_uid: 0/0 debug1: identity file /root/.ssh/identity type -1 debug1: identity file /root/.ssh/id_rsa type 1 debug1: identity file /root/.ssh/id_d........

LVM How-To Activate and Access Volumes/Data

vgchange -ay 3 logical volume(s) in volume group "vg_12" now active lvscan inactive '/dev/vg_12/lv_root' [144.04 GB] inherit inactive '/dev/vg_12/lv_home' [1.00 GB] inherit inactive '/dev/vg_12/lv_swap' [7.85 GB] inherit........

mdadm recover from dead drive

mdadm --manage /dev/md3 --add /dev/sda1 cat /proc/mdstat Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] md0 : inactive sdd2[1] sdd1[2](S) 31270272 blocks md3 : active raid1 sda1[2] sdb1[1] sdc1[3](F) 943730240 blocks [2/1] [_U] [>....................]........

Bad Hard Drive Slows Down Computer

Here's a proven example of what a bad hard drive can do, it was technically functioning OKin a RAID array but the system became extremely low and the load become high and IOWAIT was even higher and I always thought it was a bad application. The truth is that this failing 1TBHitachi has slowly gotten worse and caused huge slowdowns, (eg. 100% load on Thunderbird waiting for e-mails to load etc..). After swapping it out, tabs change instantly, emails are not lagged, and........

Nearly 100% CPU Usage from processes called dma0chan0 dma0chan1 dma0chan2 dma0chan3

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I separated the 2 drives in the RAID 1 array. 1 is the old one /dev/sda and is out of date, while the separated other one /dev/sdc was in another drive and mounted and used with more data (updated). I wonder how mdadm will handle this: usb-storage: device scan complete md: md127 stopped. md: bind md: md127: raid array is not clean -- starting background reconstruction raid1: raid set md127 active with 1 out of 2 m........

mdadm Linux Software RAID QuickStart Guide

Create New RAID 1 Array: First setup your partitions (make sure they are exactly the same size) In my example I have sda3 and sdb3 which are 500GB in size. mdadm --create /dev/md2 --level=1 --raid-devices=2 /dev/sda3 /dev/sdb3 mdadm: array /dev/md2 started. Check Status Of The Array *Note I already have other arrays md0 and md1. You can see below that md2 is syn........

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For a standalone system the solution is simple, just use the same version of Windows a copy a good version of: C:windowsSecurityDatabasesecedit.sdb from another computer. Then you should be able to login again without getting the nasty message "Local policy does not permit you to log on interactively." Of course you will probably need a way of accessing the filesystem off-line in order to get to it such as a Linux boot disc. Some........

md: kicking non-fresh sda1 from array! - fix/solution

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mdadm when a RAID 1 member dies

[27969.398749] sd 5:0:0:0: [sdb] 3907029168 512-byte hardware sectors (2000399 MB) [27969.398749] sd 5:0:0:0: [sdb] Write Protect is off [27969.398749] sd 5:0:0:0: [sdb] Mode Sense: 00 3a 00 00 [27969.398749] sd 5:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [27972.117543] ata6.00: exception Emask 0x0 SAct 0x1 SErr 0x0 action 0x0 [27972.117543] ata6.00: irq_stat 0x48000000 [27972.117543] ata6.00: cmd 60/08:00:ff:7........

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FUSE/Curlftpfs mount ftp account as drive partition in Linux

This is a great way to use your ftp server space, for example on your web hosting account (althoughI believe many hosts don't allow storage like this), but if you have a VPS/Dedicated Server etc.., this would be perfect. Imagine how easy it is to work with an ftp account that you can just mount as a normal partition or directory in Linux, it would be great for backups etc.. Name curlftpfs - mount a ftp host as a local directory Synopsis........

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mdadm can you downgrade the superblock?

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Which one does the OS care about? blkid says the UUID is "787f1fa4-b010-4d77-a010-795b42884f56" while md insists its UUID is "4d96dd3b:deb5d555:7adb93cb:ce9182d9" When in doubt, do we assume the OS takes the one from blkid? /dev/md0: UUID="787f1fa4-b010-4d77-a010-795b42884f56" TYPE="ext3" [root@localhost ~]# mdadm -D /dev/md0 /dev/md0: Version : 0.90 &........

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I successfully created a single RAID 1 partition which includes /boot inside it and my root directory through the Debian installer. It said GRUB installed successfully but when I try booting the OS it seems GRUB can't read anything. When trying to boot from GRUB GRUB Loading stage 1.5. GRUB loading, please wait... Error 2 I get "Error 2" when trying to boot Debian. I also notice from a LiveCD that........

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I installed 5.5 with a 300GB RAID 1 partition (boot is also on this partition). It booted up fine the first few times until after I used a Live CD and accessed the array, and it became named /dev/md127 for some reason. Now whenI boot into CentOS I get a kernel panic and different errors, once I got "invalid superblock", even though the array is fine (it didn't happen again, probably because I was sure to dismount and stop the mdadm array properly). Here's what........

mdadm Linux Software RAID auto-detect and assemble RAID Array

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rsync halted froze Out of memory: kill process 7559 (rsync) score 635 or a child Killed process 7559 (rsync)

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Convert HDD/Hard Drive Partition(s) into non-RAID into RAID 1 using existing data without data loss and without reformatting.

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