.pQd's log – Page 3 – Just another WordPress weblog

UNION instead of OR in MySQL

i have MySQL that is run on arrays of increasing size: i remembered that the query optimizer will not be able to use existing indices for lastModified columns but.. the query execution time was acceptable, so i did not bother. recently much more data was added and query above, repeated quite often, caused a lot ... Read More

balkans

travelLeave a Comment

i’ve sepnt two August/September weeks traveling with my parents from Dubrovnik via Sarajevo and Zagreb to Budapest. short brain-dump with hiking maps follows.

OVH, failover IPs, IPv6, VMs

techipv6, linux networking, ovhLeave a Comment

at work we rent a dedicated server from OVH; except unexplained openvpn throttling all is working pretty well for the price we pay. besides primary IPv4 address OVH can provide few additional ‘failover’ IPv4 addresses and /64 IPv6 subnet. in our setup some of IPv4s and IPv6s are routed to a KVM VM. below – ... Read More

Dell PowerEdge T20

tech4 Comments

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.

around Gran Canaria

travelLeave a Comment

i’ve spent 2 weeks at the beginning of March at Gran Canaria. below – list of the more interesting walking trails we’ve taken.

sphinx text search – sorting the results by relevancy

techsphinx searchLeave a Comment

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

hk, mc, sg, my

non-tech, travelhong kongLeave a Comment

some walking trails i’ve taken during my last trip to Hong Kong, Macau, Singapore, Malaysia.

pigz –rsyncable, rdiff

techbackups, linux, mysql, rsyncLeave a Comment

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

hu/sk/at/cz

travelLeave a Comment

a brain-dump from my recent trip to Hungary, Slovakia, Austria and Czech Republic.

chrooted bind9 with geodns under debian wheezy

tech1 Comment

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

tech1 Comment

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

[somewhat] byzantine backup setup

tech3 Comments

below – a description of somewhat convoluted backup system that so far have been serving me pretty well.

installation of debian wheezy on mdadm raid1 + gpt

tech22 Comments

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

tech1 Comment

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.

hk/mc/sg/vn

travelhong kongLeave a Comment

i got another chance to visit Asia. instead of suffering cold, dark and cold January in Sweden i’ve spent 3 weeks in mild Hong Kong & Macau, tropically hot Singapore and pleasantly warm Vietnam.

raspberry pi

techlinux networkingLeave a Comment

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

ansible – centralized configuration management…

techansible, ccm, puppetLeave a Comment

… that did not drive me crazy so far.

3+ weeks in Portugal

travel3 Comments

i’ve been thinking about working remotely for a few weeks from some warm[er] country for quite some time. finally i’ve tried – i’ve spent 3+weeks in Portugal while taking just 2 days of holidays. all went surprisingly well.

balkans – again

travelLeave a Comment

so i’ve hit the road again – packed my trusted 8-10yo travel bag, took laptop, camera + 3 lenses, kindle with 400+documents waiting to be read or deleted, mp3 player, gps, two mobile phones, earplugs, some old clothes and nothing more. i’ve even left intentionally at home travel guides borrowed from the local library – ... Read More

agentless monitoring of linux servers from ossec

techossec6 Comments

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