I have WowzaStreamingEngine 4.0.4, no incoming or outgoing streams at the moment, and Wowza Streaming Engine Manager usage graph says that 15.49GB of 16GB (nearly 99%) is being used. This is constant without fluctuation.
I sincerely hope that the graph is very wrong. Otherwise, something is very wrong with my server. Has anyone else seen this? Any insight into why I do?
Hi there, can you please provide some more information about your setup and usage?
For example, are you using any custom modules?
Thanks.
salvadore
Hi,
You have actually used 14849(used) - 13544(cached) = 1305GBytes
The cached amount is how much the OS is caching data, more than likely files, and it frees this when needed by applications.
Andrew.
Hi,
Yes, you are right, it should read 1305MB and it should also have the buffers amount added; so another 148MB is available.
This is just how Linux reports the memory usage. The cached memory is usually what is used by the OS to cache file writes & reads to and from the hard drives. If you turn this off, you will most likely have performance issues. Buffers are normally used by the network adaptors to buffer incoming and outgoing traffic.
High cache values indicate that there is a lot of disk io occurring. This would be the case if you are running VOD applications or have a lot of recording going on. If the cache is consuming all of the memory, it may be indicating that you need faster disks or more memory.
Wowza Streaming Engine can only see the total and used values and reports based on these. It cannot see the cached or buffered values so cannot take these into account.
Roger.
Hi,
The OS does keep stuff in the cache for a long time. I’m not even sure it clears it out until the memory is needed elsewhere.
I guess as long as you have some free memory listed then it shouldn’t be an issue.
You can run the following command as root which will clear the cache.
sync; echo 3 > /proc/sys/vm/drop_caches
Note: You shouldn’t use this command when the server is busy as it stops everything else while the command runs and can take a few seconds to complete if the cache is really full.
Roger.
Hi there, can you please provide some more information about your setup and usage?
For example, are you using any custom modules?
Thanks.
salvadore
No, I am not using any custom modules. My server specs are:
Dedicated Dual Intel Quad Core L5420 2.5 Ghz Server with 16GB RAM. OS is Ubuntu 13.10 64-bit.
I used the command line free -m, and it showed:
total-------used------free----shared----buffers-----cached
16048----15813-----234----0-----------148---------13544
When I stopped the Wowza Streaming Engine service:
total------used-------free----shared—buffers----cached
16048----14849-----1199—0---------148--------13544
Not a huge difference with WSE running or not running.
Hi,
You have actually used 14849(used) - 13544(cached) = 1305GBytes
The cached amount is how much the OS is caching data, more than likely files, and it frees this when needed by applications.
Andrew.
I believe that that should be 1305MB (about 1.3GB).
So, in essence, when Wowza needs more memory, it has the other 13+ Gigs to use? Is this common? What are the pros and cons of having this memory cached? If this is the only (or best) way, I hate that the Wowza dashboard looks like there is no memory left. I would like to know what really is being used.
Okay, this website offers a very clear explanation: http://www.linuxatemyram.com/
Looks like the cached memory actually helps applications run faster. Too bad that the Wowza dashboard did not reflect this (used - cached = memory used). Maybe that can be in the next upgrade?
Hi,
Yes, you are right, it should read 1305MB and it should also have the buffers amount added; so another 148MB is available.
This is just how Linux reports the memory usage. The cached memory is usually what is used by the OS to cache file writes & reads to and from the hard drives. If you turn this off, you will most likely have performance issues. Buffers are normally used by the network adaptors to buffer incoming and outgoing traffic.
High cache values indicate that there is a lot of disk io occurring. This would be the case if you are running VOD applications or have a lot of recording going on. If the cache is consuming all of the memory, it may be indicating that you need faster disks or more memory.
Wowza Streaming Engine can only see the total and used values and reports based on these. It cannot see the cached or buffered values so cannot take these into account.
Roger.
This server is used by a church who streams 2-3 times /per week. I am trying to build a system that will allow me to stream other churches smoothly. Wowza archives the video on the server, but there is no io activity at the moment, as I am the only one with access to the archives at this point. Does the statement about high cache values still apply in this case?