2,313 reputation
79
bio website marksverbiage.blogspot.com
location Reading, United Kingdom
age 39
visits member for 5 years, 7 months
seen Nov 28 '12 at 17:32
Experienced developer; I use stuff like MySQL, perl, work on pretty large systems.

Nov
28
comment 10 second SSH delay prior to successful login
It appears (on my system) that the problem is client-side and related to IPv6. It does a number of futile IPv6 lookups before trying IPv4.
Nov
28
comment 10 second SSH delay prior to successful login
@mjk: How would it KNOW that it's a 192.168 connection before it's used DNS?
Nov
28
comment 10 second SSH delay prior to successful login
I have the same problem and I'm SURE it's not caused by DNS. I have a working DNS infrastructure, and disabling all DNS options makes no difference.
Oct
24
comment Too many httpd processes running and CentOS server freeze
Can you access the Apache server-status page to see what all those httpds are doing? Is anything showing up in your error log?
Feb
27
comment enable mysql 5.5 for php
Good, you are using Oracle's official mysql binaries. This is the way to get a well-tested mysql server package.
Feb
21
comment mysql server, open 'dead' connections
Each thread needs a stack, which allocates some address space, typically 256k or 1M. Each thread stack needs to be contiguous and not crash into another thread's stack. This consumes and fragments address space, until the server cannot function any more and starts failing. Do not use 32-bit systems for production servers. No hardware which is still in warrantee exists which does NOT run a 64-bit OS.
Jan
17
comment Why are there so many processes running?
This is not definitely the case; "ps" generally doesn't show threads by default if you use a recent (i.e. not ancient) libc / threads package and 2.6. kernel, which the OP seems to be using.
Nov
29
comment Duplicate primary keys in MySQL table due to DoS attack
Consider switching to innodb, in careful consulation with the application developers, as part of a properly managed change which is fully tested. Be careful. It is a good idea though, in the broader sense.
Nov
29
comment Looking for the fastest web server
If it is an intranet, it is highly unlikely that you will get 10,000 connections; intranets have the advantage that you can find the size of your audience easily, and it cannot grow beyond the staff of the company (excepting things like company mergers). However, most intranet sites run web applications not static web sites, so you'll want to optimise the application, not the web sevrer (which really doesn't matter in that case)
Nov
28
comment Looking for the fastest web server
Also, if you're really serving high volumes of static content, you will find it more cost effective (again, bandwidth cost, not servers!) to use a CDN (content-delivery network) and let them worry about it.
Nov
28
comment Looking for the fastest web server
If you have 10,000 connections, the bandwidth will cost you a lot of money; therefore you'll be able to afford a newer server. Additionally, servers are not a major component of the cost of hosting commercial web sites; datacentre space/power, and bandwidth are far more significant. Any web server can fill up a 1Gbit pipe on a modest machine on most workloads.
Sep
8
comment Querying a Large Dataset Fast: MySQL MEMORY (HEAP) engine, MyISAM, or something else (e.g. MemCached)
InnoDB and MyISAM will also keep the data in memory when it is so small; the memory engine doesn't support BTREE indexes so it falls down if you need to do range scans. InnoDB is a better general purpose engine with MVCC and other features.
Sep
6
comment Why does wget get redirected to localhost when fetching an unresolvable page?
Spot on. It was using my host's official host name as a search path, and THEIR DNS had a dodgy wildcard entry. Thanks for your help.
Sep
6
comment Why does wget get redirected to localhost when fetching an unresolvable page?
Thanks for your reply, but Google Public DNS always returns an NXDOMAIN, as my transcript showed.
May
30
comment MySQL Locking Up
An InnoDB query cannot hold up MyISAM ones, are you sure that your application isn't doing something like LOCK TABLES? Additionally, how is your RAM tuned? It may be that you have failed to tune it adequately for the hardware. Mixed MyISAM / InnoDB servers are always a compromise, doing neither efficiently.
May
30
comment MySQL Locking Up
Can you reproduce the problem on a development system? Can you post a) the table schema, from SHOW CREATE TABLE, b) The output from SHOW FULL PROCESSLIST at the time of the problem (you may need to santitise this if it contains production data)
Mar
23
comment “TCP Sweep” - What is it? How am I causing it?
Sounds like the box needs to be pulled out immediately. Restore your backups carefully.
Mar
7
comment How to grow from single server setup
If you have enough free RAM, and mysql is being slow to answer read queries, you don't have mysql tuned right. use the ram for the database instead. MySQL's caching will be entirely transparent to the application, not introduce bugs and never return stale data.
Feb
22
comment Are .pid files reliable for determining whether a process is running?
The existence of the pid file, COMBINED with the existence of the process however, should be sufficient. If the process quit, you can check that. PIDs do get reused, but not very often.
Feb
11
comment Low Overhead Linux Server Install for MySQL
They have stopped shipping us the PE1950, it is obsolete. This machine is fairly old?