Category: storage / NAS / QNAP

for even better overview, it is possible to label harddisks & partitions like this: # this can be done on mounted ext4 / ext3 / ext2 partitions # swap partitions can not be labeled tune2fs -L “LABEL” /dev/sdaX # with […]

for some reason… did ext3 on RAID1 with two disks (seagate + wd) of different sized (2TB but they (of course) are not not exactly 2TB) not sure where the problem here was 1) kernel 2) ext3 3) the disks… […]

Byte The term byte was coined by Werner Buchholz in June 1956,[4][13][14][b] during the early design phase for the IBM Stretch[15][16][1][13][14][17][18] computer, http://archive.computerhistory.org/resources/text/IBM/Stretch/pdfs/Buchholz_102636426.pdf backup mirror: PLANNING A COMPUTER SYSTEM BROJECT STRETCH Buchholz Campbell_102636426.pdf which had addressing to the bit and […]

if hfs+ is greyed out in gparted there is hfs+ compatibility software missing hint: sudo should be up and running, or gparted won’t be able to open a display (as root) and won’t be able to create partitions (as non […]

to recover the data: how to mount luks2 encrypted volume possibility: remove harddisk, attach to sata2usb adapter, then mount on different machine like this: # unlock encrypted harddisk udisksctl unlock -b /dev/sdb5 udisksctl mount -b /dev/mapper/ubuntu–vg-root Mounted /dev/dm-1 at /media/dpm/e8cf82c0-f0a3-41b3-ab28-1f9d23fcfa72 […]

btw: love kvm (used by very large companies) just as virtualbox (oracle) the task: over the years a windows vm is using up massive amounts of precious server harddisk space (snapshots before everyupdate) all the snapshots now add up to […]

update: while this benchmark is still valid, very simple, very cross platform, with a focus on the team cpu (why is there no multi core md5? (putting many many core arm servers at disadvantage) + harddisk (two very important components) […]

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 was initially written by Linus Torvalds on the idea: how to create source code management system that does not suck. source code management is very useful when the developer team is larger than > 1 developer. it allows fast […]

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 […]

especially in times of EU-GDPR–DSGVO but also for the user’s privacy effectively shredding data is important. if the admin-user wants to wipe-shred-secure-delete entire harddisks look at this article. GNU Linux Debian 10 can do that 🙂 # install software # […]

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) requirements: server: have OpenSSH installed allow root login […]

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 […]

update: safety first! when it comes to important files: safety comes first thus recommend to the user that wants to go pro the following backup system: have two complete backups at two different places: backupA: at the company, USB 3.0 […]

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 […]