24 de fev de 2010

Zimbra 6.0 e Centos 5.4

1. Instalar Centos
2. Editar /etc/hosts
127.0.0.1 localhost.localdomain localhost
xx.xx.xx.x webmail.domain.xx webmail
3. yum update -y
4. yum install compat-db gmp compat-libstdc++-296 compat-libstdc++-33 libtool-ltdl sysstat
5. yum remove sendmail
6. yum install fetchmail
6. Desactivar os serviços, exim, cups e bluetooth
7. chkconfig --level 0123456 exim off
8. Editar o ficheiro /etc/sudoers e comente a linha “defaults requiretty”
9. Editar o ficheiro /etc/sysconfig/i18n e deletar a linha LANG=”en_US.UTF-8”.
10. Executar
tar xvfz zcs-6.0.1_GA_1816.RHEL5.20090911181524.tgz
cd zcs-6.0.1_GA_1816.RHEL5.20090911181524
11. ./install.sh --platform-override
12 Quase no final da instalação, se tudo correu bem, o zimbra apresentará uma mensagem de erro, a informar que localhost.localdomain é um endereço inválido.
Setting defaults…No results returned for A lookup of localhost.localdomain
Checked nameservers:
XXX.XX.XXX.X
XX.XXX.XX.XXX
Ajuste as configurações de hostname e domain name.
DNS ERROR resolving localhost.localdomain
It is suggested that the hostname be resolveable via DNS
Change hostname [Yes] Please enter the logical hostname for this host [localhost.localdomain] zimbra.dominio.com
DNS ERROR resolving MX for zimbra.dominio.com
It is suggested that the domain name have an MX record configured in DNS
Change domain name? [Yes]
Create Domain: [zimbra.dominio.com] dominio.com
MX: zimbra.dominio.com(XXX.XX.XXX.XX)
Interface: XXX.XX.XXX.XX
Interface: 127.0.0.1
done.

12. Após ajustar o hostname e o domain, será apresentado um menu com várias configurações do zimbra. É necessário fazer algumas configurações
No menu 3) Zimbra Store Recomendo alterar:
4) Admin Password
12) Web server mode – De http para redirect, assim todo o acesso http é automagicamente redirecionado para https, adicionando um pouco mais de segurança para o usuário final.
No menu 1) Common configuration, ajustar o 6) TimeZone
Recomendo passar nos outros menus para verificar se as outras configurações a fim de refletirem o seu ambiente. Observar também se os endereços mostrados correspondem ao seu hostname e domínio.
Após o término da configuração, use a opção “a” para salvar e aplicar as novas configurações. O instalador passará por mais alguns pontos e com sorte, o processo estará finalizado em alguns minutos.

13. E já está

SNMP Ubuntu

Como instalar SNMP no Ubuntu

1. sudo apt-get install snmpd

2. mv /etc/snmp/snmpd.conf /etc/snmp/snmpd.conf.org

3. Criar /etc/snmp/snmpd.conf file:

rocommunity public
syslocation "xxxxxxxxxxxxxx"
syscontact email@localhost

4. Edit /etc/default/snmpd alterar

# snmpd options (use syslog, close stdin/out/err).
SNMPDOPTS='-Lsd -Lf /dev/null -u snmp -I -smux -p /var/run/snmpd.pid 127.0.0.1'

para

# snmpd options (use syslog, close stdin/out/err).
#SNMPDOPTS='-Lsd -Lf /dev/null -u snmp -I -smux -p /var/run/snmpd.pid 127.0.0.1'
SNMPDOPTS='-Lsd -Lf /dev/null -u snmp -I -smux -p /var/run/snmpd.pid -c /etc/snmp/snmpd.conf'

5. /etc/init.d/snmpd restart

Event ID 13042

Event Type: Error
Event Source: Windows Server Update Services
Event Category: Clients
Event ID: 13042
Date: 6/25/2009
Time: 6:58:56 AM
User: N/A
Computer: localhost
Description:
Self-update is not working.

Andava já à algumas semanas com este erro no meu servidor WSUS e não percebia muito bem o porque de ele não estar a actualizar como deve de ser. Já tinha testado varias coisas mas nada tinha funcionado, até que hoje de manha depois de mais alguma pesquisa resolvi o problema.

O que é que se passava? Aqui a uns tempos instalei no mesmo servidor do WSUS a consola de administração do Symantec Endpoint Protection. Durante a instalação ele reconfigurou o DefaultWebsite do IIS, apagando uma virtual directory essencial para o correcto funcionamento das actualização do servidor WSUS. A correcção é simples.


1. Abrir IIS Manager apartir Administrative Tools

2. No website a correr na porta 80,criar uma virtual directory chamda 'Selfupdate'.

3. Apontar para 'C:\Program Files\Update Services\Selfupdate'.

4. Confirmar que a o acesso anonymous está activado.

5. Activar o 'Directory Browsing' na directo

E assim o problema desapareceu.

Link


23 de fev de 2010

Entender os contadores de performance (Performance Counters)

Segue uma descrição dos principais contadores que muitas vezes recorremos para medir a performance de um sistema

Understanding Performance Counters data while troubleshooting Performance issues
To troubleshoot overall Database system performance issue, analyzing performance counters is the best way to start. By collecting performance counters during busy period for few days consistently and analyzing those data would give a better idea about overall system problems regarding Memory, CPU, and/or Disk I/O. Please note, for troubleshooting a particular SQL problem such as a stored procedure or a piece of T-SQL, it is better to look at the query execution plan and SQL Trace data and identify the need of redesigning a query or table indexes.

Some key performance counters to use while assessing a performance issues on SQL Server.
Memory:
Memory and Disk I/O complements each other. Memory issues on the system could affect disk I/O and vice versa. It is very critical to carefully observe the trend of performance counters data over a long period of time to identify the real problem.

· Memory\Available Mbytes

Threshold: A consistent value of less than 20 to 25 percent of installed RAM is an indication of insufficient memory.
Significance: This indicates the amount of physical memory available to processes running on the computer. Note that this counter displays the last observed value only. It is not an average.

· Memory\Page Reads/sec

Threshold: Sustained values of more than five indicate a large number of page faults for read requests.
Significance: This counter indicates that the working set of your process is too large for the physical memory and that it is paging to disk. It shows the number of read operations, without regard to the number of pages retrieved in each operation. Higher values indicate a memory bottleneck.

If a low rate of page-read operations coincides with high values for Physical Disk\% Disk Time and Physical Disk\Avg. Disk Queue Length, there could be a disk bottleneck. If an increase in queue length is not accompanied by a decrease in the pages-read rate, a memory shortage exists.

· Memory\Page Input/Sec:

Threshold: The value should not exceed 15. Higher the value poor the performance.

Significance: Pages Input/sec is the rate at which pages are read from disk to resolve hard page faults. Hard page faults occur when a process refers to a page in virtual memory that is not in its working set or elsewhere in physical memory, and must be retrieved from disk.

· Memory\Pages/sec

Threshold: Sustained values higher than five indicate a bottleneck.
Significance: This counter indicates the rate at which pages are read from or written to disk to resolve hard page faults. To determine the impact of excessive paging on disk activity, multiply the values of the Physical Disk\ Avg. Disk sec/Transfer and Memory\ Pages/sec counters. If the product of these counters exceeds 0.1, paging is taking more than 10 percent of disk access time, which indicates that you need more RAM. If this occurs over a long period, you probably need more memory.

A high value of Pages/sec indicates that your application does not have sufficient memory. The average of Pages Input/sec divided by average of Page Reads/sec gives the number of pages per disk read. This value should not generally exceed five pages per second. A value greater than five pages per second indicates that the system is spending too much time paging and requires more memory (assuming that the application has been optimized).

Processor
To measure processor utilization and context switching, you can use the following counters:

· Processor\% Processor Time

Threshold: The general figure for the threshold limit for processors is 65 percent.
Significance: This counter is the primary indicator of processor activity. High values many not necessarily be bad. However, if the other processor-related counters are increasing linearly such as % Privileged Time or Processor Queue Length, high CPU utilization may be worth investigating.

· Processor\% Privileged Time

Threshold: A figure that is consistently over 75 percent indicates a bottleneck.
Significance: This counter indicates the percentage of time a thread runs in privileged mode. When your application calls operating system functions (for example to perform file or network I/O or to allocate memory), these operating system functions are executed in privileged mode.


· System\Context Switches/sec

Threshold: As a general rule, context switching rates of less than 5,000 per second per processor are not worth worrying about. If context switching rates exceed 15,000 per second per processor, then there is a constraint.
Significance: Context switching happens when a higher priority thread preempts a lower priority thread that is currently running or when a high priority thread blocks. High levels of context switching can occur when many threads share the same priority level. This often indicates that there are too many threads competing for the processors on the system. If you do not see much processor utilization and you see very low levels of context switching, it could indicate that threads are blocked.

Disk I/O
To measure disk I/O activity, you can use the following counters:

· PhysicalDisk\Avg. Disk Queue Length

Threshold: Should not be higher than the number of spindles plus two.
Significance: This counter indicates the average number of both read and writes requests that were queued for the selected disk during the sample interval.

· PhysicalDisk\Avg. Disk Read Queue Length

Threshold: Should be less than two.
Significance: This counter indicates the average number of read requests that were queued for the selected disk during the sample interval.

· PhysicalDisk\Avg. Disk Write Queue Length

Threshold: Should be less than two.
Significance: This counter indicates the average number of write requests that were queued for the selected disk during the sample interval.

· PhysicalDisk\Avg. Disk sec/Read

Threshold: No specific value.

Less than 10 ms – very good

Between 10-20 ms – okay

Between 20-50 ms – slow, needs attention

Greater than 50 ms – Serious I/O bottleneck


Significance: This counter indicates the average time, in seconds, of a read of data from the disk.

· PhysicalDisk\Avg. Disk sec/Transfer

Threshold: Should not be more than 18 milliseconds.
Significance: This counter indicates the time, in seconds, of the average disk transfer. This may indicate a large amount of disk fragmentation, slow disks, or disk failures. Multiply the values of the Physical Disk\Avg. Disk sec/Transfer and Memory\Pages/sec counters. If the product of these counters exceeds 0.1, paging is taking more than 10 percent of disk access time, so you need more RAM.

· PhysicalDisk\Disk Writes/sec

Threshold: Depends on manufacturer's specification.
Significance: This counter indicates the rate of write operations on the disk.

· Physical Disk: %Disk Time

Threshold: Greater than 50 percent, it represents an I/O bottleneck

Significance: Represents the percentage of elapsed time that the selected disk drive was busy servicing read or write requests.

· Physical Disk\Avg. Disk Reads/Sec and Physical Disk\Avg. Disk Writes/Sec

Threshold: It should be less than 85% of the disk capacity

Significance: It represents the rate of read operations on the disk.

When using above counters, you may need to adjust the values for RAID configurations using the following formulas.

Raid 0 -- I/Os per disk = (reads + writes) / number of disks

Raid 1 -- I/Os per disk = [reads + (2 * writes)] / 2

Raid 5 -- I/Os per disk = [reads + (4 * writes)] / number of disks

Raid 10 -- I/Os per disk = [reads + (2 * writes)] / number of disks

For example, you have a RAID-1 system with two physical disks with the following values of the counters.

Disk Reads/sec 80

Disk Writes/sec 70

Avg. Disk Queue Length 5

In that case, you are encountering (80 + (2 * 70))/2 = 110 I/Os per disk and your disk queue length = 5/2 = 2.5 which indicates a border line I/O bottleneck.

Disk I/O issues can be minimized by having larger and sequential I/O activities. To achieve than you should consider partitioning. Partitioning can be done in many ways – Database partitioning, Tempdb partitioning, Table partitioning, index partitioning. At a minimum, it is highly recommended to partition your database in such a way that clustered index, non-clustered index, and transaction logs are each on a separate physical drive and spread across multiple logical filegroups/files within that drive.

Hello world

Hello world