.pQd

kvm: disabled by bios

by .pQd
does your kvm VM feel sluggish? mine did feel pretty slow.. as it turned out virt-install quietly overrode ‘hvm’ preferences and created a fully emulated qemu vm when it failed to make use of hardware-assisted virtualization.

bios upgrade on Dell PowerEdge T20 via AMT

by .pQd
prepare the floppy image file that later can be mounted via AMT, include in it just the bios update file – in my case it was PET20A18.exe from here. once the file is ready use the Manageability Commander Tool > Remote Control > Take control mount such img file as a virtual, oversize floppy. Using ... Read More

bridging lan segments across untrusted links

by .pQd
we’ve run out of the office space in one of the locations. in short term it was not possible to find a suitable and large enough place to rent so we had to split and relocate some of the staff to another building few kilometers away. it’s possible that we’ll shuffle people and servers between ... Read More

multi-master mysql replication with servers on 3 different continents

by .pQd
at work i’m using mysql replication quite extensively. first it was a straightforward one-way replication that has been rock-solid for us since 2009. in 2012, for another type of data, we’ve started using master-master setup. initially the servers were in different European countries, eventually the secondary site was moved to North America while primary one ... Read More

idrac upgrade failures

by .pQd
idrac gives you “RED006: Unable to download Update Package” and plenty of headaches during updates? it happened to me while jumping over few updates and going straight from 2.41.40.40 to 2.52.52.52. no amount of racadm racreset would help. upgrading first to 2.50.50.50 and only then to 2.52.52.52 did the trick for me.

MySQL on BTRFS?

by .pQd
i’ve been running a set of production MySQL databases on BTRFS since April 2016. BTRFS is not exactly known for its stellar performance when hosting databases or images of virtual machines due to its COW nature. why would i do it then? to have data snapshots and be able to ‘go back in time’ quickly ... Read More

A wall of text on bad and good choices

by .pQd
In this line of work, you don’t just get to play with shiny toys having plenty of blinking lights. There’s plenty of choices to be done nearly every day. Choices or rather bets: some of the technologies, software stacks, products or services provided internally will eventually be a flop. Decisions made over the years are ... Read More

E5-2643 in r620 stuck at a very low cpu frequency

by .pQd
few weeks ago i’ve done a general firmware upgrade of 2 identical Dell Poweredge r620 servers. a while later i’ve noticed that one of them had really sluggish performances. i’ve noticed that /proc/cpuinfo has shown CPU frequencies of hundreds of MHz rather than thousands. cat /proc/cpuinfo |grep MHz gave me 16 rows of values between ... Read More

lxc broken after upgrade from linux-image-4.12.0-0.bpo.1-amd64 to linux-image-4.13.0-0.bpo.1-amd64

by .pQd
lxc containers no longer start after i’ve upgraded debian stretch server from 4.12 kernel from stretch-backports repository to 4.13 also from backports. symptoms in /var/log/syslog: that was resolved by creating /etc/systemd/network/99-default.link with: via this comment. then there was nothing interesting in syslog but the lxc guest still would not start – lxc-start -F -n serverName ... Read More

btrfs and nfs dont play nicely together

by .pQd
i use ghettoVCB to take backups of vmware esxi 6.5 vms. data is copied to a nfs share hosted on Debian Linux. for over a year i used btrfs partition as an underlying datastore for the nfs share. and i just could not get it to work for backups which size larger than available RAM ... Read More

ucarp and vmware esxi

by .pQd
i’ve moved a linux router from 9yo physical box to a vm running under esxi 6.5. it’s a designated master in pair of master / slave managed by ucarp. it took me a while to figure out why it was not working – why didn’t the slave ‘see’ the master machine? as it turned out ... Read More

opendkim failing to start after recent routine debian update

by .pQd
on 2017-10-12 i’ve done a routine apt-get update; apt-get upgrade on a debian stretch vm that, among other services, runs opendkim service that adds a digital signature in the headers of the outgoing mails. during the update i was asked weather to keep or replace the /etc/opendkim.conf; as usual in such cases i’ve answered no ... Read More

bridge on vlans on active-backup bonding under debian stretch

by .pQd
i use this setup for few lxc servers. bonding provides me layer2 failover based on arp probes [ so it’ll work even if switch link stays up yet forwarding fails the mechanism will kick in ]. this is continuation of an earlier post, this time under debian stretch

“out of range” on drac console when booting debian stretch

by .pQd
i’ve installed debian stretch on an old dell poweredge 2950. after booting it i saw grub, few lines from kernel and then green screen with “out of range”: reboot, on the grub menu select “*Debian GNU/Linux”, press e, hilight a line with linux /boot/vmlinuz-4.9.0-3-amd64 root=/dev/sda1 ro quiet, add there vga=normal fb=false nomodeset and press ctrl+x ... Read More

sphinxsearch reborn as manticoresearch?

by .pQd
for the past year number of commits in my favorite open source text-search server – the sphinxsearch project – has dropped to nearly 0. looks like in the meanwhile some of the old contributors moved to another project – manticoresearch. the website of the new project features two prominent supporters – craigslist and boardreader. fingers ... Read More

unwanted wordpress trackback spam

by .pQd
today i’ve learned that disabling trackback in wordpress’s settings > discussion [ ] Allow link notifications from other blogs (pingbacks and trackbacks) on new articles is not enough. your old posts, created before the date when this check-box was un-ticked, will still allow trackback which might be spammy. solution? adjust the trackback setting on per-post ... Read More

varying svn checkout times under virtualized windows server 2016

by .pQd
we’ve set up a new build server using Windows Server 2016 running under ESXi 6.5. few days later devs came back with a complain: full svn checkout time varies a lot – it takes between 1 and 8 minutes. steps taken that hopefully resolved the issue: disable the icon cache of tortoise svn, then eventually ... Read More

bridging two physical interfaces of esxi server

by .pQd
my colleagues got into an unpleasant situation where one of two dedicated servers, running vmware esxi 6.0, rented from a datacenter lost its network connectivity. the datacenter/internet-facing interface is down, hours later, during regular working day, the hosting provider did not react and resolve the problem. maybe the network card died, maybe switch port misbehaves ... Read More