When you first encounter LiteSpeed Web Server (LSWS), choosing the right license or even the right LSWS edition can be difficult. This wiki will explain the differences between different editions and licenses (focusing more on licenses) and then go over some ways to help decide which license is right for you.
There are three different editions of LiteSpeed Web Server. (See the feature comparison on the main site for an in-depth comparison.)
LiteSpeed Web Server Enterprise Edition has 6 different licenses to choose from. These licenses reflect how much power LiteSpeed Web Server will be given. Generally, the licenses are divided by how many cores LSWS will have access to, though there are two special, more affordable licenses only for VPSs.
Notes: VPS and Ultra VPS licenses will not install on a dedicated server or a VPS over their respective RAM limits. If the concurrent connection limit is surpassed, extra connections will be queued until there is room in the connection limit. Currently supported VPS platforms are KVM, HyperV, Virtuozzo, OpenVZ VPS, XEN, VMWare and UserModeLinux VPS.
You do NOT need to buy a license to match the number of CPUs or cores on your physical server. The number of CPUs in the license title simply denotes the number of cores the LSWS process will be able to utilize. LSWS is fast and lightweight enough to run very, very well on only a fraction of the server's cores. In almost all cases, you are better off buying a license for a fraction of your server's cores and leaving the other cores for heavier processes like PHP and MySQL.
Note: Hyper-threads do NOT count towards your core total.
We offer free 15 day trial licenses. These licenses are 2-CPU licenses. Using a trial license may be a good way to figure out if LSWS is right for you and what license you want.
Often, finding exactly the right license for your usage is a matter of trial and error. Different sites put pressure on different parts of the server. The best approach may be to purchase a license, then try upgrading or downgrading to see if it affects your service noticeably. You can upgrade or downgrade at any time and you will only be charged (or credited) the difference in the license fee for the remainder of the billing period.
For example, if you have a 4-core server and run LSWS, PHP, and MySQL on the same server, you can buy 1 or 2-CPU license, as your other CPU power will be fully utilized by PHP and MySQL processes. Usually for a 4-core server, you will not need anything higher than a 2-CPU license if you have other external applications like PHP or RoR.
This requires more CPU power for encryption.
These are served by LSWS directly, so more CPU will help. If your server is mainly PHP/MySQL powered, a 4-CPU license may not help much as LiteSpeed will not be the bottleneck.
Like all other lightweight web servers, blocking disk I/O will block LiteSpeed's process. Therefore, if your server has high I/O wait, you should consider a higher CPU license in order to compensate. Since version 4.1, LiteSpeed has supported AIO (asynchronous IO).
There is limit for max concurrent connections for different licenses. The free version has a limit of 150, the VPS license, 500, Ultra VPS, 600, and the Enterprise edition is unlimited. You can check the number of concurrent connections used from the real-time report under web admin console, or use the command
netstat -an | grep 80 | grep ESTA | wc -l
Remember, though, only “established” connections from netstat output are considered to be concurrent. For example, a forum with 3,000 users online might only use 300 concurrent connections, as those 3,000 users do not all execute actions at the exact same split second.