Tag Archives: server configuration

How can I tell if I'm using hardware or software RAID?

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I recently acquired an HP Proliant DL380 2U rackmount server. One can reasonably expect a rackmount server boasting 6 hot-swappable hard drive bays also to sport hardware RAID. But how can you be sure? What about that tower you inherited from a hobbyist sysadmin who claims that it "has hardware RAID", but can't tell you what the RAID controller card is.

This might not work for everyone, but it's a good start. Comments are welcome; I'm happy to add more info to the original article.

This question on ServerFault is currently a prominent search result for "how can I tell if I'm using hardware or software RAID". I thought I'd contribute my personal experience and add that, in Linux, cat /proc/mdstat will show your software RAID configuration (assuming the md kernel module, which is probably a fairly safe bet).

If you're using software RAID, you'll see something like

Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sda1[0] sdd1[2] sdb1[1]
     1465151808 blocks level 5, 64k chunk, algorithm 2 [4/3] [UUU_]
    unused devices: <none>

(Snippet source and further reading.)

If not, you'll see

Personalities :
unused devices: <none>

You can also check the output of dmraid --sets, whose output is fairly clear (no RAID and you'll get no block devices found back).

Hardware RAID implementations vary. Some provide logical devices in /dev/sdX, some (like the Compaq Computer Corporation Smart Array 64xx (rev 01) in my HP Proliant) use /dev/cciss/c0d0.

Further reading:

 

(This post originally took the format of an answer on ServerFault, which unfortunately incurred the wrath of someone who hadn't yet had their morning coffee; I've converted it to this blog post in the spirit of learning and sharing.)

Compiling xslcache 0.7.1 for PHP 5.4

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We make heavy use of xslt at work (parsing xml data generated by php controllers), so the xslcache pecl module is pretty fundamental to our infrastructure. Of course, if you are using PHP 5.4 or above, like many pecl modules, it breaks. Here's how to get it to work.

Currently, trying sudo pecl install xslcache-beta with PHP >= 5.4 throws the following error at make:

/tmp/pear/temp/xslcache/php_xsl.c: In function 'xslcache_objects_new':
/tmp/pear/temp/xslcache/php_xsl.c:211:52: error: 'zend_class_entry' has no member named 'default_properties'
make: *** [php_xsl.lo] Error 1
ERROR: `make' failed

Download xslcache

Download the original source from the pecl svn repository, the 5.4 patch, and patch it manually:

svn checkout http://svn.php.net/repository/pecl/xslcache/trunk xslcache
cd xslcache
wget -O php_xsl.c.patch 'https://bugs.php.net/patch-display.php?bug_id=62856&patch=xslcache-php5.4-compat&revision=1362641549&download=1'
patch < php_xsl.c.patch

Make and install

This is a pretty straightforward make process for most linux software (you may need to adjust the location of xslcache.ini):

phpize
./configure
make
make test
sudo make install
sudo nano /etc/php5/cgi/conf.d/xslcache.ini
#add "extension=xslcache.so"

Note that if you make test the tenth may fail with the following:

=====================================================================
FAILED TEST SUMMARY
---------------------------------------------------------------------
Test 10: EXSLT Support [tests/xslt010.phpt]
=====================================================================

If you're using XSLT 2.0, you probably don't need to worry about it.

Verify that xslcache is installed and enabled

Since we're already in the command line, let's check there:

php -i | grep XSLCACHE

Hopefully, you will see the following line:
XSLCACHE => enabled
Furthermore, you should be able to actually know it's doing its job because your benchmarks should improve.

Compiling xhprof for PHP 5.4

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We use xhprof to profile our web application framework. The pecl installer was failing with `[xhprof.lo] Error 1` in the make phase with PHP 5.4. Here's how to fix that.

Currently, trying
sudo pecl install xhprof-beta
throws the following errors in the `make` phase for PHP >= 5.4:

In file included from /usr/include/php5/main/php.h:33:0,
from /tmp/pear/temp/xhprof/extension/xhprof.c:27:
/usr/include/php5/main/php_config.h:2396:0: warning: "_GNU_SOURCE" redefined [enabled by default]
/tmp/pear/temp/xhprof/extension/xhprof.c:24:0: note: this is the location of the previous definition
/tmp/pear/temp/xhprof/extension/xhprof.c:236:1: warning: 'visibility' attribute ignored [-Wattributes]
/tmp/pear/temp/xhprof/extension/xhprof.c:240:28: warning: 'visibility' attribute ignored [-Wattributes]
/tmp/pear/temp/xhprof/extension/xhprof.c: In function 'hp_get_function_name':
/tmp/pear/temp/xhprof/extension/xhprof.c:898:10: warning: assignment discards 'const' qualifier from pointer target type [enabled by default]
/tmp/pear/temp/xhprof/extension/xhprof.c:909:13: warning: assignment discards 'const' qualifier from pointer target type [enabled by default]
/tmp/pear/temp/xhprof/extension/xhprof.c:911:13: warning: assignment discards 'const' qualifier from pointer target type [enabled by default]
/tmp/pear/temp/xhprof/extension/xhprof.c:930:34: error: 'znode_op' has no member named 'u'
/tmp/pear/temp/xhprof/extension/xhprof.c:963:9: warning: passing argument 1 of 'hp_get_base_filename' discards 'const' qualifier from pointer target type [enabled by default]
/tmp/pear/temp/xhprof/extension/xhprof.c:856:14: note: expected 'char *' but argument is of type 'const char *'
/tmp/pear/temp/xhprof/extension/xhprof.c: In function 'hp_execute_internal':
/tmp/pear/temp/xhprof/extension/xhprof.c:1650:24: error: 'znode_op' has no member named 'u'
/tmp/pear/temp/xhprof/extension/xhprof.c:1651:59: error: 'struct <anonymous>' has no member named 'return_reference'
/tmp/pear/temp/xhprof/extension/xhprof.c:1652:25: error: 'znode_op' has no member named 'u'
/tmp/pear/temp/xhprof/extension/xhprof.c: In function 'hp_compile_file':
/tmp/pear/temp/xhprof/extension/xhprof.c:1683:3: warning: passing argument 1 of 'hp_get_base_filename' discards 'const' qualifier from pointer target type [enabled by default]
/tmp/pear/temp/xhprof/extension/xhprof.c:856:14: note: expected 'char *' but argument is of type 'const char *'
make: *** [xhprof.lo] Error 1
ERROR: `make' failed

According to a PHP bug report, this issue was fixed by Facebook but not made available on pecl, so you will need to install from the xhprof github repo, like so:

wget https://github.com/facebook/xhprof/archive/master.zip
unzip master.zip
cd xhprof-master/extension/
phpize
./configure
make
sudo make install

And enable the module in your php.ini, where `xhprof.output_dir` is the directory into which profiles will be generated.

[xhprof]
extension=xhprof.so
xhprof.output_dir="/var/tmp/xhprof"

And restart apache, with either of the following two:
sudo service apache2 restart or sudo apachectl graceful

Existing users who have upgraded to PHP 5.4 may opt for this xhprof-0.9.2 patch.