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Serty Oan's questions

Martin Hope
Serty Oan
Asked: 2010-10-06 01:10:22 +0800 CST
  • 0

Here is the configuration :
Bugzilla (3.4.2) application running on a Ubuntu server 8.04 with Perl 5.8.8.

Here is the problem :
Sometimes (randomly), pages take very long to load. It can be any of the login page or query.cgi page or buglist.cgi... etc...
Using top on the server, I tried to see what was wrong, and saw that sometimes a bugzilla script would use 30% memory and last pretty long (1 to 5 seconds) and sometimes not even show in the list because it responded too quickly or just use 2%. The mysqld process does not seems to be the problem.

perl bugzilla cpu-usage
Martin Hope
Serty Oan
Asked: 2010-06-19 01:15:17 +0800 CST
  • 0

This is the opposite question of this one. My purpose is that there is no need when you write only PHP5 code to have PHP4 compatibility. It is not helpful at all and due to differences between object models in those two version, it must be penalizing on interpreter performances (or am I wrong ?).

So my questions are :

  • is it possible to recompile PHP5 without retrocompatibility with PHP4 or to disable it in any other way to gain performances ?
  • if it is not possible, is there a project somewhere which aim that goal ?
performance php
Martin Hope
Serty Oan
Asked: 2010-06-17 00:01:41 +0800 CST
  • 3

I was wondering if, and how much, using tmpfs could improve MySQL performance and how it should be done ? My guess would be to do mount -t tmpfs -o size=256M /path/to/mysql/data/DatabaseName, and to use the database normally but maybe I'm wrong (I'm using MyISAM tables only).

Will a hourly rsync between the tmpfs /path/to/mysql/data/DatabaseName and /path/to/mysql/data/DatabaseName_backup penalize performances ? If so, how should I make the backup of the tmpfs database ?

So, is it a good way to do things, is there a better way or am I losing my time ?

performance linux mysql tmpfs
Martin Hope
Serty Oan
Asked: 2010-05-29 03:08:24 +0800 CST
  • 10
  • Client : OpenSSH_5.1p1 Debian-5ubuntu1 (Ubuntu 9.04)
  • Server : OpenSSH_5.1p1 Debian-5 (Proxmox 2.6.24-7-pve)

I use SSH to execute commands remotely on the server (module check_by_ssh of Nagios). But SSH hangs from time to time when trying to execute commands. I can log to the server via SSH but not executing a simple 'ls'. And it seems to block from all clients from the same IP address. Authentication is not the problem, may it be made by SSH keys or password.

ssh -l root -p 2222 server.domain.tld 'ls'

Here the client debug info

debug1: Entering interactive session.
debug2: callback start
debug2: client_session2_setup: id 0
debug1: Sending environment.
debug3: Ignored env ORBIT_SOCKETDIR
*** skipping approx 40 env var ignored
debug1: Sending command: ls
debug2: channel 0: request exec confirm 1

It hangs there. Then after a random time, it works again (without doing anything). Killing all sshd process on the server seems to work too. It works from a Putty. I saw that some people had trouble like this due to ISP reverse DNS problem, but it does not seem to be the case here.

It can work for hours and then not work for half an hour or so.

What could explain this behaviour ?

EDIT : Seems that with -t or -T option, ssh does not hang, but I can't pass one of these options in the check_by_ssh of nagios

ssh