apt update apt upgrade is what users do… having no idea of the “heart attack” momentum that is awaiting them X-D after a reboot… and 1min 30sec timeout, the dreaded Control+D give root password prompt appears. “Houston we have a […]
git is not only good for crowds of developers having to organize and sync “status quo” of the project over various devices, users also use it for version control of documents and various other files (anything where organized cooperation between […]
recompressing mobile phone videos can save significant amount of (precious ssd) disk space. it is very cpu intense – so either bring massive amounts of cpu power or massive amounts of runtime 🙂 on 4x threads Core(TM) i5-4200U CPU the […]
all infos about one’s harddisk: # tested on: hostnamectl Static hostname: centos.localdomain Operating System: CentOS Linux 7 (Core) CPE OS Name: cpe:/o:centos:centos:7 Kernel: Linux 4.15.9 Architecture: x86-64 # software needed: install smart monitoring tools yum install smartmontools.x86_64 # nice overview: […]
mdadm -E /dev/sd[a-z] # -E, –examine # Print contents of the metadata stored on the named device(s). # Note the contrast between –examine and –detail. # –examine applies to devices which are components of an array, while # –detail applies […]
spoiler alert: this is work in progress… was told by Adaptec support to upgrade firmware. did not do that yet – because firmware upgrades on production systems are sometimes very risky endeavors. one of the most important features of a […]
… because maybe one wants to read their smart status. # tested on: hostnamectl Operating System: CentOS Linux 7 (Core) CPE OS Name: cpe:/o:centos:centos:7 Kernel: Linux 5.X Architecture: x86-64 # and also: hostnamectl Static hostname: storagepc Operating System: Debian GNU/Linux […]
monitoring the integrity of a RAID is critical for fast replacement of failed harddisks (ideally one has at least one spare drive already in the machine) if not – it would be great if hard- and software-raid would send a […]
problem: manually changing uuids is tidious and might not yield the result you want. unfortunately have not succeeded yet with integrating an old harddisk.vdi (same uuids) back into the template vm (same uuids) – so the recommendation is: reinstall os […]
# where is what? lsblk -o “NAME,MAJ:MIN,RM,SIZE,RO,FSTYPE,MOUNTPOINT,UUID” NAME MAJ:MIN RM SIZE RO FSTYPE MOUNTPOINT UUID sda 8:0 0 838.3G 0 ├─sda2 8:2 0 837.3G 0 crypto_LUKS 23c92dca-43f2-4a55-80cf-acfecb0ca482 │ └─luks-23c92dca-43f2-4a55-80cf-acfecb0ca482 253:0 0 837.3G 0 LVM2_member aXsFmd-a5wn-tP5p-AM2k-Jmx3-Sdhn-0vT911 │ ├─centos-root 253:1 0 50G […]
tested on: CentOS Linux 7 with Kernel: 3.10.0-957 with cifs-utils.x86_64 version: 6.2-10.el7 when you ping the host (in this case a QNAP NAS) you – as the administrator – quickly realize – the host is up. but samba client (cifs […]
it is super slow, but for copying small files it works. if /mnt/cifs/here is owned by non-root user, also non-root users are allowed to mount. (which is rather tricky with mount cifs) # setup software apt install sshfs yum install […]
in comparison to Y2K: “The issue became when it became 2000 because that would be stored as 00 in the program. This caused many to believe that say, bank software wouldn’t be able to get your money out because it […]
this is a very very basic sequential harddisk write test performed on host and guest. there are multiple ways, how you could improve the performance: Use fixed size disks Allocate RAM and CPUs wisely Install the Guest Additions enable host […]
Amazing machine! – Streaming Netflix BigBang with 20Watts… odroid_h2_overview_datasheed_hardware.pdf streams 1080p from youtube “effortless” cpu hits it’s limits with 4k youtube (firefox) as fast as a i5 while using very little energy 10 W idle / 20 Watts during “average” […]
kernel 3.10, software raid1 works fine… kernel 4.18, software raid1 seems to work fine… kernel 4.19, software raid1 miserably fails… it starts to sync raid1 discs becomes slower and slower and finally “120 seconds….” then comes to a halt. i […]
update: 2019-02: everything was fine… until you decided to update because of the EthernalBlue exploit THAT ALSO AFFECTS OPEN SOURCE IMPLEMENTATIONS OF SMB 1.0! (WTF!? WHY?), samba now miss behaves on Debian and CentOS. (scroll down for details) EternalBlue, sometimes […]
You might want to checkout very basic sequential write/read benchmark with dd. You might also want to checkout: cross os harddisk benchmark iozone and java. ============ OS and Kernel Linux server4.localdomain 4.15.7 #1 SMP Sun Mar 4 16:43:40 CET 2018 […]
REM delete all mapped network drives net use * /DELETE /Y REM map two drives net use W: “\\192.168.0.233\SharedFolderA” /persistent:yes /user:usernameA PaSsWorDA net use T: “\\192.168.0.231\SharedFolderB” /persistent:yes /user:usernameB PaSsWorDB what you need to know: windows CAN NOT establish two connects […]
what? a simple file wise rsync based backup of your system (currently without boot partition or boot manager) that: does exclude mountpoints on debian and centos – thus really only backups your internal root partition /dev/sda (probably) automatically creates subdirectory […]
While the Supermicro X8DT3 CPU: 2x Xeons with 2x Intel Xeon(R) CPU E5504 @ 2.00GHz and RAM: 64GB RAM EEC Dual-Powersupply is a great mainboard with java remote web IPMI console that allows you to access the bios and remote […]
You might want to checkout very basic sequential write/read benchmark with dd. You might want to checkout iozone in c harddisk benchmark. this benchmark is especially useful if you need to measure how java is performing on your harddisk/filesystem/os (linux […]
yes ext3 is old – but it works and you can undelete files – which can come in handy – because nobody is perfect – except god – and nobody should assume he/she is god. it supports filesystems up to […]
ext3+gnu_linux+samba = fast and reliable fileserver. WARNING! Security problems Versions from Version 3.5.0 to 4.6.4 (recent in May 2017 ) are affected and need to be patched! patches are available from: https://www.samba.org/samba/patches/ Unfortunately EVEN Debian9 (!!!! GUYS FIX THAT FAST […]
checkout the tutorial: http://jperrin.org/centos/monitoring/grafana/keeping-an-eye-on-centos-performance-with-grafana/ maybe cacti and co is too complicated and looks a little outdated… collectd might be just what you are looking for 🙂 “The main objective of this is to develop an easy to use and customizable […]
The Enterprise Volume Management System (EVMS) Project has the goal of providing unparalleled flexibility and extensibility in managing storage. It represents a new approach to logical volume management for Linux. The architecture introduces a plug-in model that allows for easy […]
you should setup harddisk encryption during setup. to add an encrypted /home partition afterwards might be possible but a lot more effort. scroll very down if you want to know how to encrypt an usb sticks … needless to say […]
might be also interesting: https://dwaves.de/2019/09/08/linux-bash-script-iterate-over-all-harddisks-in-the-system-and-check-their-smart-status/ and: https://dwaves.de/2019/09/06/linux-server-monitor-software-raid-mail-notification-on-failure/ harddisks… are blackboxes of data – if something fails… you do not repair – you replace. 65% of all harddisk failurs can be announced with smart. wohoo! so don’t rely on it 😀 […]
btrfs is used by SUSE12 for the /root partition – where it is doing daily snapshots of the installed OS. It has more functionality built-in than just storing files. This article wants to take btrfs for a test-drive. Video Tutorials: […]
update: extundelete works well on ext3 but kind of failed me on ext4. tools to try: http://trinityhome.org/Home/index.php?wpid=61&front_id=12 get an overview: what harddisk/partition is what? lsblk; # more detailed lsblk -o “NAME,MAJ:MIN,RM,SIZE,RO,FSTYPE,MOUNTPOINT,UUID” alias harddisk=’lsblk -o “NAME,MAJ:MIN,RM,SIZE,RO,FSTYPE,MOUNTPOINT,UUID”‘ harddisk NAME MAJ:MIN RM SIZE […]