Performance Improved in cPanel 11.25 DNS Clustering
cPanel DNS clustering utility, DNSAdmin, now sends updates in batches with a single call, reducing the server’s memory consumption during DNS synchronization.
cPanel have also added a feature that will automatically disable unresponsive cluster members, preventing outdated information from being sent to up-to-date servers when the unresponsive server come back online. Plus, cPanel simplified reconfiguring and restarting BIND into a single call, speeding up the process.
Tags: 11.25, clustering, cpanel, DNS, Performance
sar - Collect, report, or save system activity information.
To have sar read a particular data file, use the -f /var/log/sa/saDD option. You can select multiple files by using multiple -f options. Since many of sar’s reports are lengthy, you may want to pipe the output to a file.
To create a basic report showing CPU usage and I/O wait time percentage, use sar with no flags. It produces a report similar to this:
01:10:00 PM CPU %user %nice %system %iowait %idle
01:20:00 PM all 7.78 0.00 3.34 20.94 67.94
01:30:00 PM all 0.75 0.00 0.46 1.71 97.08
01:40:00 PM all 0.65 0.00 0.48 1.63 97.23
01:50:00 PM all 0.96 0.00 0.74 2.10 96.19
02:00:00 PM all 0.58 0.00 0.54 1.87 97.01
02:10:00 PM all 0.80 0.00 0.60 1.27 97.33
02:20:01 PM all 0.52 0.00 0.37 1.17 97.94
02:30:00 PM all 0.49 0.00 0.27 1.18 98.06
Average: all 1.85 0.00 0.44 2.56 95.14
“The %user and %system columns simply specify the amount of time the CPU spends in user and system mode. The %iowait and %idle columns are of interest to us when doing performance analysis. The %iowait column specifies the amount of time the CPU spends waiting for I/O requests to complete. The %idle column tells us how much useful work the CPU is doing. A %idle time near zero indicates a CPU bottleneck, while a high %iowait value indicates unsatisfactory disk performance.”
Tags: activity, Collect, Information, report, SAR, System
VirtFS and Jailshell
When terminating an account, the VirtFS mounts for the account are removed.
The VirtFS mounts for an account are cleared when changing the shell of the account. This only happens automatically when using the Manage Shell Access interface in WHM.
Session Disruption
If a user has an active jailshell session when the Administrator changes the user’s shell, the user’s connection is terminated. This is necessary to allow successful removal of the bind mounts used in the jailshell environment.
Tags: Jailshell, VirtFS
HTTP Error 502 Bad Gateway, 503 Service Unavailable
This error is usually due to improperly configured proxy servers. However, the problem may also arise when there is poor IP communication amongst back-end computers, when the client’s ISP is overloaded, or when a firewall is functioning improperly.
The first step in resolving the issue is to clear the client’s cache. This action should result in the a different proxy being used to resolve the web server’s content.
503 Service Unavailable
This error occurs when the server is unable to handle requests due to a temporary overload or due to the server being temporarily closed for maintenance. The error signifies that the server will only temporarily be down. It is possible to receive other errors in place of 503.
Tags: 502, 503, Bad, error, Gateway, HTTP, service, unavailable
cPanel & WHM Version Number
The version number:
The first and second segments still represent the parent and major values. (These are unchanged.)
The third segment no longer consists of an auto-incremented build ID number. It now represents a milestone—a group of changes to cPanel & WHM that will include new features and bug fixes.
The fourth segment is the auto-incrementing build ID. This value is relative to the milestone. When the milestone is achieved, the third segment will be incremented and the build ID will reset to 0.
For example, in version 11.29.1.4:
“11” is the parent number.
“29” is the major version number.
“1” is the cPanel & WHM milestone.
“4” is the build ID leading up to the completion of the milestone.
This version number would be reported in the cPanel & WHM user interfaces as “11.29.1 (build 4).”
Tags: cpanel, Number, Version, WHM
