CentOS Mail Server setup: Postfix, Dovecot, Virtual users, MySQL, SASL, Postfixadmin, TLS

I've compiled a cleaner guide for CentOS + Postfix + Virtual users + SASL + PostfixAdmin. At this moment it's not complete yet, it's missing SSL/TLS configuration for Dovecot and Postfix, i'll add it soon. Check the guide here.

Apache .htaccess: how to get rid of 'RewriteEngine not allowed here'

Apache error: RewriteEngine not allowed here

A friend of mine has changed his web hosting server, and since that moment one of it's web pages stopped showing. The page displayed instead was a generic page from the Apache web server, telling that there was an internal error and to check the logs.
Here's a line from the log:

[Tue Aug 25 17:07:39 2009] [alert] [client xx.xx.xx.xx] /usr/local/www/htdocs/.htaccess: RewriteEngine not allowed here

I tried to find the answer on the net, and after a short google search and after reading a little bit of apache docs, I found the answer.


How this appeared?

My friend's web site includes a file called .htaccess, which usually is populated with directives for the apache web server. In a default apache setup, this file is read on web page access, but only if the main configuration directives (from httpd.conf or vhost configuration file) allow this. This is specified by the 'AllowOverride AuthConfig' directive. Since I've seen the error, AllowOverride AuthConfig was 'On', so the .htaccess file was processed, but some of it's content is not permitted in this context.


How to allow RewriteEngine on directive in .htaccess

All I needed to do is to modify the apache configuration file referring to htdocs directory. In my case it was the virtual host definition file, but it may be the main apache config file, httpd.conf. I've changed the <directory> section from

<Directory /path/to/htdocs/>
Options +FollowSymLinks
AllowOverride AuthConfig
Order allow,deny
Allow from all
<Directory>

to

<Directory /path/to/htdocs/>
Options +FollowSymLinks
AllowOverride AuthConfig FileInfo
Order allow,deny
Allow from all
<Directory>

And it fixed the problem.

SAS RAID controllers for VMWare ESXi

Entry level SAS/SATA RAID controllers for a small server or a fast workstation
This list contains the entry-level/value SAS/SATA RAID controllers with internal ports, as listed by VMWare I/O compatibility tool on 2009-08-13. If you use or intend to use a controller with external ports, or a controller from other vendors (HP, DELL, fujitsu, IBM etc) do a check on VMWare web site, I haven't listed here all the SAS/SATA RAID controllers. I need to have this nicely formatted, so I can find easy where to choose from if i need a SAS/SATA controller for a small server, or a workstation, since most controllers are compatible with Windows too. For Windows the list could be much longer, since not all SAS RAID controllers are tested by VMWare, I only put here the ones that may be useful for a VMWare ESXi server running on a DIY platform. There may be many other SAS/RAID controllers usable with VMWare, but these listed below are definitely usable for VMFS volumes.
Adaptec Entry level / value SAS/SATA RAID Controllers compatible with VMWare ESX

• Adaptec RAID 2405: Entry level SAS/RAID controller, 4 internal ports, low profile form factor, 800 MHz processor, PCI Express x8. Supports RAID levels 0, 1, 10, 128 MB DDR2 cache memory, up to 128 SAS or SATA drives using SAS expanders. Supports ESX / ESXi 4.0. Price: ~ $270 (US)
• Adaptec RAID 3405: Value line SAS/RAID controller, 4 internal ports, Low profile form factor, Intel 80333 500 MHz processor, PCI Express x4 bus interface. Supports RAID levels 0, 1, 1E, 5, 5EE, 6, 10, 50, 60, JBOD, using 128 MB cache memory. Supports up to 128 SATA or SAS drives using SAS expanders, optional battery backup. Supports ESX/ESXi 4. Price: ~ $400 (US)
• Adaptec RAID 3805: Value line SAS/RAID controller, 8 internal ports, Low profile form factor, Intel 80333 500 MHz processor, PCI Express x4 bus interface. Supports RAID levels 0, 1, 1E, 5, 5EE, 6, 10, 50, 60, JBOD, using 128 or 256 MB cache memory. Supports up to 128 SATA or SAS drives using SAS expanders, optional battery backup. Supports ESX/ESXi 4. Price: ~ $575 (US)
• Adaptec RAID 31205: Value line SAS/RAID controller, 12 internal ports, half-length/full-height form factor, Intel 80333 800 MHz processor, PCI Express x8 bus interface. Supports RAID levels 0, 1, 1E, 5, 5EE, 6, 10, 50, 60, JBOD, 256MB ECC cache, up to 128 SATA or SAS devices using SAS expanders, optional battery backup. Price: ~ $795 (US)
• Adaptec RAID 31605: Value line SAS/RAID controller, 16 internal ports, half-length/full-height form factor, Intel 80333 800 MHz processor, PCI Express x8 bus interface. Supports RAID levels 0, 1, 1E, 5, 5EE, 6, 10, 50, 60, JBOD, 256MB ECC cache, up to 128 SATA or SAS devices using SAS expanders, optional battery backup. Price: ~ $995 (US)

Intel Entry level / value SAS/SATA RAID Controllers compatible with VMWare ESX

• Intel® RAID Controller SRCSAS144E: Mid-range (Mainstream) PCI-E SAS controller, PCI Express x4 bus interface, 4 internal ports, 4 external ports, Low profile PCI: 7.71" x 2.535" form factor, Intel IOP 80333 processor at 500 MHz, LSI 1068 3.0 GB/s SAS/SATA IO controller, supports up to 32 devices via expanders, 128 MB embedded memory, audible alarm. Price: $549 at NewEgg, without cables.
• Intel® RAID Controller SRCSASRB: Mid-range (Mainstream) PCI-E SAS controller, Low profile, extended half-length (7.75" x 2.525") form factor, PCI Express x4 bus intreface, 256 MB ECC DDR2 cache memory, LSI1078 SAS ROC (RAID on Chip) at 500 MHz and dual-independent DMA controllers. Supports RAID Levels 0, 1, 5 and 6, 10, 60, 60, online capacity expansion, enclosure management, SMART. Supports up to 32 devices, through two SFF8087 mini-SAS 4i internal connectors. It uses Intel® Smart Battery AXXRSBBU4. Price: ~ $375.
• Intel® RAID Controller SASWT4I is a PCI-E SAS Controller, with 4 internal ports. It is built around LSI1064E chip, a well-known chip used by many server boards. It is able to use RAID levels 0,1,1E,10E. According to Intel's documentation, this controller is verified to work with ESX3 and ESXi3.

LSI Entry level / value SAS/SATA RAID Controllers compatible with VMWare ESX

• LSI MegaRAID SAS 8344 ELP SAS RAID Adapter: Mid-range (Mainstream) PCI-E SAS controller, PCI Express x4 bus interface, low profile form factor, 4 internal ports, 4 external ports, supports up to 32 devices via expanders, RAID levels 0, 1, 5, 10, 50, max. 32 drives (4 per port using expanders), 128 MB embedded cache memory, audible alarm. Price: unknown. This controller looks identically to Intel RAID Controller SRCSAS144E.
• LSI MegaRAID SAS 8708ELP: Value line eight-port PCI Express SAS Controller, low profile form factor, PCI Express x4, LSI SAS 1078 RAID on Chip (ROC) (500 MHz power-pc processor, hardware RAID 5 & 6 parity engines), 129 MB DDRII cache, optional battery backup unit, RAID levels 0, 1, 5, 6, 10, 50, 60, auto-resume (rebuild, reconstruction), online capacity expansion, online RAID level migration, single controller multipath, I/O load balancing, two Mini-SAS SFF-8078 x4 connectors.

HP SAS/SATA RAID controllers compatible with VMWare ESX

• HP SmartArray E200. This is a 8-port SAS/SATA RAID controller with PCI Express x4 bus interface. Form factor: SmartArray E200/64MB: full height PCI Express long card. RAID levels supported: 0,1,0+1. RAID 5 is available with 128MB Battery-Backed Write Cache (BBWC) upgrade option. It seems that HP prefers to put reliability first with this controller, because the controller disables a SATA hard disk drive's write cache, making it unable to write faster than 11 MB/sec at default settings. Fortunately, drive's write cache can be re-enabled by HP Array management tools. Yes... these tools may require a running operating system with HP smart Array tools installed (ESXi may not be suited for this task), but there is a solution. A second note regarding this card: it is a VERY long card (more than 30 cm), and it may require hard disk drive relocation or a new case, if not used in a system with E-ATX motherboard/case. I can confirm that it fits into Antec Sonata III 500, if used with a dual PCI-Express x16 motherboard, like Gigabyte EP45-UD3P, mounted on the second PCI-Express x16 slot.

IBM SAS/RAID controllers compatible with VMWare ESX

• IBM ServeRAID-BR10il SAS/SATA Controller v2 is a small form factor (MD2) controller built around LSI 1064E, PCI Express x4 bus interface and 2MB flash memory. RAID levels supported: 0,1, 1E. Stripe size is fixed, 64KB. The drives can be attached through an SFF 8087 mini-SAS connector, only internal drives, up to 14 disks.This controller does not support more than 2 logical volumes or SAS / SATA drive mixing.

You can check my Amazon Associates Store for availability and pricing.

There are some losses when using ESXi and some RAID controllers: it's possible to loose the advantages of using RAID configuration and monitoring tools like 'Adaptec Storage Manager', so you must check your arrays by other means.