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"load" and "disk" in console
Posted: Fri Aug 05, 2016 9:49 pm
by alabamatoy
What do these mean? I tried to search for this, but these words are used so much it really didnt find what Im after.
DF shows less than 2% useage of the disk ZM is supposed to writing to, but the zm console shows 7%.
Code: Select all
Filesystem 1K-blocks Used Available Use% Mounted on
udev 1962848 0 1962848 0% /dev
tmpfs 396432 6264 390168 2% /run
/dev/sda1 134439176 5014884 122572044 4% /
tmpfs 1982148 405196 1576952 21% /dev/shm
tmpfs 5120 4 5116 1% /run/lock
tmpfs 1982148 0 1982148 0% /sys/fs/cgroup
/dev/sdb1 941881932 15232480 878781548 2% /zmdata
tmpfs 396432 28 396404 1% /run/user/108
tmpfs 396432 0 396432 0% /run/user/1000
I have seen load go as high as 5.something....at what point do I need to be concerned?
Re: "load" and "disk" in console
Posted: Sat Aug 06, 2016 10:38 am
by loxodograph
Briefly,
gives you information about free space in the filesystem – both real partitions and ramdisks. The optional '-h' gives results in human-readable (sic) units (e.g., GB, MB, etc) rather than blocks.
The significant line in your example is /dev/shm. If ZM fills this ramdisk, it will cause Bad Things to happen. Higher resolution images and higher framerates will increase the use of /dev/shm. 21% Used (your figure) is fine.
The Load given in the ZM console represents the current CPU load. A single-core processor, working a full nominal load, will show a figure of '1,00'. This is multiplied by the number of cores, so a quad-core at full load will report '4,00'.
Another useful terminal command is htop (you will have to install it – it isn't part of the standard Ubuntu/Debian installation). You can immediately see what is taking CPU cycles (and other parameters) and see the effect of reducing, for example, the image resolution and framerate. htop also displays the Load figures (Load average, towards the top right of the terminal display).
Easy overview of Load average:
http://www.howtogeek.com/194642/underst ... e-systems/
More about Load in ZM:
https://wiki.zoneminder.com/Managing_Load
Re: "load" and "disk" in console
Posted: Tue Aug 09, 2016 6:40 pm
by alabamatoy
loxodograph wrote:The significant line in your example is /dev/shm. If ZM fills this ramdisk, it will cause Bad Things to happen. Higher resolution images and higher framerates will increase the use of /dev/shm.
So if I add a second HDD, would it then be wise ALSO to move /dev/shm to that new separate single-purpose HDD, along with /var/cache/zoneminder/images and same/events ?
Also, thanks much for the insight and links. Very helpful.
Re: "load" and "disk" in console
Posted: Wed Aug 10, 2016 9:10 am
by loxodograph
alabamatoy wrote:... would it then be wise ALSO to move /dev/shm to that new separate single-purpose HDD, along with /var/cache/zoneminder/images and same/events ?
No, it doesn't work like that. /dev/shm isn't a physical partition, it's a ramdisk. This is a portion of RAM configured for use in the same way as a physical disk partition (over-simplification), but with one important advantage over physical disks, both rotating hard drives and SSDs – it is very fast. In ZM, it is the shared memory, to allow processes to pass data between themselves.
In theory, it could be a physical disk partition, but with dire consequences for disk I/O and system performance. Leave it where it is.