Dell PowerEdge T20

i’ve bought 2x Dell PowerEdge t20 – they’ll serve as HA pair of routers/vpn endpoints/file servers for a new office. it was the first time i played with intel amt. it’s not bad but neither perfect.

sphinx text search – sorting the results by relevancy

a while ago i helped a colleague with moving away from mysql-based text search based on MATCH .. AGAINST to sphinxsearch to improve the performance. without much surprise this helped a lot to improve the response time. recently i was asked to take a look at the setup again and see if we can do ... Read More

openvpn throttled from ovh’s bhs datacenter?

for work we rent a dedicated server from OVH. it’s been 5 months now and i’m pretty satisfied with the service provided. at the initial stage we’ve bumped into a problem that was never really solved; i cannot be even 100% sure if it’s OVH’s fault. UDP-based OpenVPN connection established from OVH’s BHS datacenter to ... Read More

clipboard service, rdp

did the clipboard suddenly stopped passing text between your local computer and the remote desktop session? the first thing i do in such case is: start the task manager on the remote host go to processes, find rdpclip.exe and kill it start again rdpclip.exe on the remote host and try copy and paste again

squeezing water out of jepgs, pngs

jpegoptim can reduce size of JPG files. if used without -m option it’s lossless. apt-get install jpegoptim find . -type f -exec jpegoptim -m80 {} ‘;’ for pngs there are few tools out of which i found pngcrush to give best results. unfortunately it does not work ‘in-place’ and temporary file needs to be created ... Read More

pigz –rsyncable, rdiff

i’m backing up in total ~90GB of mysqldumps each night. the more data, the bigger pain it is.

hibernation for windows 2012 server

run cmd as admin and there: after that control panel>hardware>power options>change advanced power settings and hibernate is available that did a trick for windows 2012 server on an old poweredge 1950 server. unfortunately wake on lan refused to work despite of: in the control panel > network and internet > network connections for the lan ... Read More

vmware esxi 5.1 keeping mac address after moving to a new hardware

i had to move hard disks containing installed esxi 5.1 from one server to another. after i booted up a new server there was an unexpected surprise for me… vmware ‘kept’ the mac address assigned to the management interface from the old machine. so for a while i had duplicate mac address: legitimately on the ... Read More

chrooted bind9 with geodns under debian wheezy

at work we’ll soon make use of dns-based geo load balancing to have users in americas / asia ‘talk’ with north am site and rest of the world – with the european site. we preferred to avoid modifying the client application so the dns based solution seemed reasonable. below – quick overview of the setup ... Read More

cloning GPT disk to a smaller drive

while rescuing data from server having problems with either disk or raid controller i had to clone data from 2x 1TB RAID1 to 4x 500GB RAID10. as it turned out the space available on the destination server was 1GB less than on the source machine. shrinking the source drive with gparted-live and dd’ing over the ... Read More

installation of debian wheezy on mdadm raid1 + gpt

in branch offices i tend to install two identical pcs running linux and working in active – hot-spare setup. things evolved over time – one location has both routers running under vmware esxi on two different hosts, another – hardware raid, other – desktop-class pcs with single hard drives. hardware raids are good as long ... Read More

adventure with green drives

wd [and other vendors] sell green drives; they are reasonably cheap but have annoying tendency to spin down very very quickly. i bought recently 2x WD20NPVT-00Z2TT0 with intention of using them [in very unprofessional fashion] in PERC6 RAID1 array.

raspberry pi

few days ago, after 19 weeks of waiting, i have finally received my raspberry pi.

agentless monitoring of linux servers from ossec

we’ve been poking around ossec for a while. it’s nice and all but… i never liked the idea of opening additional ports on the production server or letting it ‘call home’ with alerts to the central monitoring machine. i prefer ‘polling’ model where central server communicates with monitoring nodes. ideally all should be done via ... Read More

poor man’s vm clonning under vsphere 5 without downtime

how to clone a virtual machine under vmware vsphere 5: using the vsphere client create a new vm with similar parameters [at least the same number and size of hard drives] using the vsphere client create a snapshot of the original vm log in via ssh as root [ to enable the ssh access check ... Read More

higher TCP ICW – real world tests

this post inspired me to check how much performance can we gain by just upgrading to more recent kernel on the internet-facing proxy servers at work.

extracting single database from a [large] mysqldump

extracting the whole database: sed -n '/^-- Current Database: `databaseName`/,/^-- Current Database: `/p' /path/to/the/fill/dump.sql > output.sql single table: sed -n '/^CREATE TABLE `tableName`/,/^\-\- Table structure for table /p' /path/to/the/fill/dump.sql > output.sql [via this blog]