Bluehost hosting is the one that looks not bad at fist. I used it for a year or two, but the only one trouble was that it had a really poor performance.
Actually this was the time when I developed my methodology for hosting comparison, in fact it appeared due to poor Bluehost performance.
The time-to-first-byte (the green line) in this picture confirms that average latency at box867.bluehost.com is about 1.5 sec.
All right, it’s quite slow. We can even sense 1.5 sec. delay without measuring. Let’s see why is it so long. First of all let’s take a look at CPU usage:
In this picture we could see that CPU spend significant amount of time waiting for an Input/Output operation completion (IOWait). Usually it means that the server is trying to read to and write from disk too often. Normally UIWait should be invisible in this graph. Let’s see if it really tries to read. For this reason I use RAM graph.
In this graph we could see that server allocates less than a half of physical memory which is a good value. Also about 3Gb is used by so called “Buffers”. This is cache for filesystem directories. It is extremely important to have enough memory for caching directories, so here everything is OK. “Cached” means cached contents of files. It is less important, but still can improve performance. In this particular server it seems that amount of memory is not sufficient for caching all the warm data and we could see a ceiling at 30Gb. Anyway 15Gb of cached files is better than nothing.
And whats about writing to disk? Unfortunately in shared hosting we could not estimate amount of read and write I/O separately because we don’t have privileged access. At least let’s see what load average is.
Load average means number of I/O operations in queue in average. In this particular server your script will have to wait for 10 others to read or write before it will get access to disk. That explains why IOwait was so high in the second graph above.
Thus I found that Bluehost’s shred server is overcrowded and it runs much more sites than it is able to do. For this reason performance is so poor and I decided to move to another hosting. Have a nice day, Bluehost!