[Xymon] Raspberry Pi Xymon Server

[Adam Goryachev]

On 12/05/15 16:45, Becker Christian wrote:
> Hi,
>
>
> i know it's an old thread, but....:
>
> I also have a Raspberrypi Model B running Xymon; i compiled version 4.3.17 on it. I have a 2GB USB stick with ext4 mounted as /opt/xymon and Xymon is installed there.
> The Xymon installation itself is running like a charm, i'm monitoring about 25 devices with it.
>
> But every now and then the filesystem in /opt/xymon seems the get destroyed. This has happened three times now; sometimes a filesystem check does the trick, sometimes not.
>
> My questions (I know this is a Xymon mailing list and not related to the Raspberrypi, but...)
> -is this because of the Raspberrypi or because of the USB stick (the stick is a "normal" stick, not an especially fast one....)
> -is an USB stick a good choice for a Xymon setup? Or is a hard disk the better choice?
>

In my experience (over a dozen RPi's, mainly trying to use them as 
remote desktop thin clients), I've had a lot of issues with the SD card 
and writes failing to that, often corrupting the FS. My "solution" 
recently is to simply use a read only filesystem, which has drastically 
improved the reliability.

Another factor is in relation to your power supply, and ensuring there 
is adequate power for both the RPi as well as your USB 
devices/peripherals. Even a momentary drop in power could crash either 
the USB drive (crash as in gets "ejected") or the RPi (as in the whole 
board crashes and you need to reboot.

You could try to disable any sort of write cache for the USB, and enable 
the ext4 features so the data and metadata are both protected by the 
journal. Another option would be to use a pair of USB drives, and 
configure with RAID1, so that any failure from one USB won't cause the 
complete system to crash (USB drives are generally rather cheap 
depending on the size required).

When the USB is "destroyed" have you tried checking the kernel logs to 
see what happened/why? If the RPi crashes at the same time, you could 
try to enable the serial port and log the kernel messages there, but if 
this is happening, then I suspect the crash is power related or similar 
since the USB shouldn't crash the whole system.

Also, don't forget there might be a write limitation on most cheap USB 
flash drives, and hobbit does a lot of small writes.... If this is the 
issue, a USB HDD should solve it.

Other than the above suggestions, I don't have a lot more to add, 
hopefully someone else can offer more.

Let us know if you find any more information....

Regards,
Adam

-- 
Adam Goryachev Website Managers www.websitemanagers.com.au