New version of OptimumCache (0.2-31) for CloudLinux 6 and CloudLinux 7 is available from our production repository.
fixup ploop is not listed via 'df -h' issue;
show de-duplication coefficient in 'optimumcache stat'.
Interpreting OptimumCache online statistics
To check cache use online statistics run:
# optimumcache stat
csums – is number of marked files (control sums) in OptimumCache, 95.4% – their percentage from total files count in Linux kernel cache;
fetched – total files count in Linux kernel cache;
uncached – number of files not in OptimumCache;
cached – number of files in OptimumCache (with percentage);
de-duplication coefficient – percentage of de-duplicated file (share the same csum) in optimum cache.
Higher value of de-duplication coefficient means bigger number of similar files and better performance.
CageFS has a mechanism to make any additional location with users content available from inside. This is a quite useful way to share needed backup directories for users if you are giving ftp/ssh access to them. Also you can use this feature to provide access to /homeabc/username when /home/username is a symlink to it.
To enable this feature the following line should be added to /etc/cagefs/cagefs.mp file:
Then cagefsctl --remount-all should be launched.
After that a user can see both his /home/username and /homeabc/username from CageFS inside. Other directories in /homeabc as well as in /home will be still hidden for him.
The way how OptimumCache does its job can be explained with an example of how WordPress single static file index.php pops up in ‘optimumcache dump’ output.
After ‘occtl --mark-dir...’ is over, try to locate WP’s index.php via ‘optimumcache dump --resolve-filenames’. The command will list that file just a few times. But you are sure that the file is spread over shared server as /home/*/public_html/index.php at least 500 times... What is happening?
Let us take in-depth look at what OptimumCache does with ‘marked’ files:
OptimumCache periodically requests the kernel for inode list being hold in FS cache at the moment.
For those inodes have csum pre-set (affected once by 'occtl --mark-dir...') OptimumCache looks a matching file in /var/cache/optimumcache/.
Whether cached file copy is not found, it is created with file csum as the key, like /var/cache/optimumcache/68/f14b3bab817862e46cb7ff4bdfa85068004e79.
The inode cache pages are (re)mapped to file /var/cache/optimumcache/68/f14b3bab817862e46cb7ff4bdfa85068004e79, instead of original file content.
This way, multiple inode instances of the same file FS cache pages get remapped to a single instance of that file in /var/cache/optimumcache68/f14b3bab817862e46cb7ff4bdfa85068004e79.
Try this command then:
# tar cf - /home/*/public_html/index.php | pv > /dev/null
and list FS cache again:
# optimumcache dump --resolve-filenames | grep 68f14b3bab817862e46cb7ff4bdfa85068004e79
68f14b3bab817862e46cb7ff4bdfa85068004e79 index.php will appear in FS cache multiple times due to side effect from being accessed by ‘tar...’ command above.
Some time after, FS cache inode list less recently used inodes may get evicted. The count of index.php will drop relatively. That is how 'optimumcache dump' cached items list has to be interpreted.
New version of mod_lsapi (0.3-6) with improved configurable experimental mode is available from our updates-testing repository.
Since version 0.3 mod_lsapi has a new option - lsapi_with_connection_pool, which can be configured in configuration file. By default this option is disabled. This is a new experimental mode of mod_lsapi, which increases performance for frequently requested php scripts (light weight or fast executed scripts).
If lsapi_with_connection_pool is On - then mod_lsapi tries to use pool of persistent connections to lsphp processes. Persistent connections significantly increase module performance to backends. mod_lsapi can keep up to 50 persistent connections for every socket name. In case if the number of connections used at the same time exceeds maximum, the module processes the next request in conventional, non-persistent mode.
lsapi_check_document_root is Off by default;
added correct patch for cPanel ssl_vhost template;
fixed status on fail (404 error fix);
use_suexec option implemented;
lsapi_check_document_root option implemented;
fixed path of php source detection on cPanel;
fixed php.ini for correct php work on cPanel;
fix for compilation flags for sulsphp in CMakeLists;
lscapi_set_backend_coredump and lscapi_terminate_backends added for backward compatibility;
lscapi_set_userdir added for backward compatibility.
New improved versions of CloudLinux 5 kernel 2.6.18-502.el5.lve0.8.85, CloudLinux 6 and Hybrid kernel 2.6.32-531.29.2.lve188.8.131.52, and CloudLinux 7 kernel 3.10.0-223.1.2.lve1.3.33.el7 are available from our production repository.
fix for CVE-2015-1805.
security fixes for CVE-2014-9322 and CVE-2015-1805.
Alt-Ruby 22-2.2.2-3 was released for CloudLinux 6. Python-cllib was updated to version 1.1-16, alt-mod-passenger was updated to version 4.0.58-18. All the packages are available from our updates-testing repository.
OptimumCache for CloudLinux - Beta Release Testing and Results
Our mission at CloudLinux is to deliver the most stable and profitable servers. When we release new features, we depend on customers like you to assist us in development of the most dependable and high-performing servers, and for that we are grateful!
We spent a couple of months running OptimumCache on several customer systems, diligently recording various server performance parameters and findings, and they didn’t disappoint.
Summary of our findings:
Average system CPU usage dropped by 30%
Average IO Wait dropped by 52%
Average total CPU usage dropped by 25%
Average disk utilization dropped by 50%
Up to 20% latency improvements for popular URLs
These are very significant improvements that should help hosting companies increase their density by an additional ~30%.
To learn more, join us for our live Webinar on June 25th at 1pm EDT/10am PDT. During this webinar we will cover important features, share our testing findings, and answer your questions.
To install OptimumCache on all your CloudLinux servers please run the following command: