[devel] комментарии по gurulabs RH9 review

[Michael Shigorin]

	Здравствуйте.
Добравшись до gurulabs'овского обзора RH9 [1], заметил несколько
интересных прикладных моментов, об которые ранее не спотыкался и
которые, как мне кажется, пересекаются со многими имеющими
хождение в @altlinux.ru темами.

Не очень сжатый пересказ:

(kernel-2.4.20/glibc-2.3.2)
---
Addition of Native POSIX Thread Library (NPTL) for standards
based threading support with impressive performance. This is
definitely a nice addition [...] Certain applications using the
old LinuxThreads API in a certain manner may no longer work [...]
* The WIN32 API translation software, WINE, suffers from this
  problem. Proper fixes are in the works, however, workarounds
  exist.
* Installing and running Oracle 9i R2 has major issues since it
  includes two different older embedded Java JVMs that don't work
  with NPTL. The solution is to stick with RHL8.0 or the
  officially supported Red Hat Linux AS edition.
---

Об это надо бы попробовать не споткнуться с размаху. :)

Кстати, тоже интересный момент:

---
Just a quick observation. The way text editors save files
normally, is to create a new file with a temporary random name,
and then move/rename the new file to name of the original. Using
this technique, if the file being edited has ACLs, the ACLs will
be lost. The Vim editor uses libacl to obtain the original ACLs,
and then add them back after the save.  It is important that
other applications that save files in the same fashion are
updated to use libacl.
---

(xf86-4.3)
---
A long overdue feature for XFree86 is the ability to change root
window screen resolution on the fly. This is now possible with
XFree86 version 4.3 thanks to work by Keith Packard and others
via the Xrandr (X Resize, Rotate and Reflection) extension. A new
command utility, xrandr, is available to perform actions from the
command line. For the point-n-click crowds, GUI utilities for KDE
and GNOME utility are under way as well.
---

Бишь "переключение разрешения на лету".  Возможно, killer feature
для J2.3, если он выходит с XF86 4.3.

(vsftpd)
---
In RHL8.0 vsftpd was run from Xinetd, now in RHL9 it runs
standalone and has it's own SysV init script. The Washington
University FTP Daemon (wu-ftpd) is no longer included with RHL9.
---

Интересно, почему standalone.

(initscripts)
---
A little known fact is that newer versions of RHL support
multiple network profiles. This is useful for machines that
commonly plug into different networks (think laptops). The easy
way to create network profiles is to use the
redhat-config-network command. The question then becomes, what
happens when you type "ifup eth0"? The behavior wasn't defined in
previous versions, however, now in RHL 9 the following behavior
is defined;

search path for:
# ifup $DEV
is:
/etc/sysconfig/networking/profiles/$CURRENT_PROFILE/ifcfg-$DEV
/etc/sysconfig/networking/profiles/default/ifcfg-$DEV
/etc/sysconfig/network-scripts/ifcfg-$DEV

A cool trick is to boot your RHL box directly into a profile from
the GRUB boot screen. To do this, create a separate
/etc/boot/grub.conf entry for each network profile, and in each
entry add the kernel argument netprofile=profilename.
---

Полезная вещь, кстати.

---
All the text processing utilities, grep, awk, sort, etc all work
significantly slower when using the Unicode UTF locale. To speed
the bootup, in the /etc/rc.sysinit and other SysV scripts,
because the configuration is using 7bit ASCII these utilities are
now invoked with  LC_ALL=C utility to force the C locale.
---

Очередные грабли с юникодом...

---
For a given Sys V init script, you can now easily control the
nice value.
---

Не то что easily, но, видимо, инит-скрипты по пакетам все же
подверглись унификации.  Мне, кстати, чем дальше, тем больше
симпатична схема в PLD -- с "макровыносом" функций.

---
The devlabel system produced by engineers at Dell and now
integrated into RHL9 solves this problem at a lower level that
can be argued is more convenient and elegant. It operates by the
system administrator defining a name by which a partition is to
be known by. This "name" is actually a symbolic link that
devlabel maintains and updates at boot time (devlabel is launched
early on in the /etc/rc.sysinit file) or by a system
administrator after boot.

Moreover it is integrated into the hot-plug system so that
hot-plug storage such as USB, Firewire, or PCMCIA storage devices
get persistent references. Imagine trying to access files stored
on a USB keychain storage device when you already have your
portable MP3/OGG player already attached. With devlabel, you can
define your MP3/OGG player to always be /dev/mp3oggplayer no
matter how many or in what order you attached other USB storage
devices.

There are also very nice benefits to devlabel in a SAN
environment where a given disk drive is /dev/sdb on one host, but
/dev/sdd on another. By using devlabel in such a setting, all the
hosts can have a persistent and common view of the device files.

Hopefully other Linux distributions will be adopting devlabel as
well.
---

Остается только присоединиться к последнему предложению.  "То, о
чем так долго говорили большевики".  Использование лейблов
действительно заметно повышает выживаемость RH против ALM.

(про вопрос initrd и raid root скромно молчу, там оно давно
работает)

(php-4.2.2)
---
The popular PHP server side scripting language has not changed
versions (4.2.2) from RHL8.0 to RHL9, however, changes in
configuration file layout has occured. The main PHP configuration
file is the /etc/php.ini as it has always been, now starting in
RHL9, there is now a /etc/php.d/ directory.
---

Еще одна SysV'изация.

(gdm)
---
One behavioral change in RHL9, is that previously in RHL8.0 GDM
was configured not to restart even if the X server was killed
with CTL-ALT-BKSP. This caused issues with PAM and the X server.
One fix was to cycle to run level 3 and back to run level 5.
[...] Now however, thanks to the AlwaysRestartServer=true entry
in the /etc/X11/gdm/gdm.conf file, this is no longer needed.

On the first boot after installing RHL8.0, because of the
firstboot app, the X server could end up on VT 8. Now the GDM
conf has been modified to force VT 7.
---

Здесь сразу бы хотелось отметить, что все эти force on VT7 и
(наши) патчики к XF86, чтобы не вылазил на VT2 -- костыли.

Ожидаемое (и логичное) поведение -- вылазенье на первой свободной
*после* запуска консоли, будь *getty в количестве 6, 10 или 2 шт.

(cups)
---
Red Hat has been shipping CUPS as an alternative to LPRng since
RHL7.3, now in RHL9 it is the default.
---

Видимо, CUPS подровняется.  Что не может не радовать.

(mozilla-1.2.1)
---
If you decided to upgrade to Mozilla 1.3 be aware that there have
been reports of Java plugin compatibility issues when using the
Sun JRE/SDK though the Blackdown JRE/SDK is reported to work
fine.
---

:-)


Также упоминается о включении subversion, mailman 2.1, kde 3.1
(которые, оказывается, умеет desktop sharing over VNC -- тоже
visible/marketable feature, кстати), etc.

[1] http://www.gurulabs.com/RedHatLinux9-review.html

-- 
 ---- WBR, Michael Shigorin <mike на altlinux.ru>
  ------ Linux.Kiev http://www.linux.kiev.ua/
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