RAM disc for web server data

[James Muirhead]

In case this is useful to anyone...

As the web server data is written to the SD every 5 minutes, I felt it would be appropriate to create a RAM disc for it. Should, in theory, improve lifespan of the SD card.

Anyhow, I just created an entry in /etc/fstab for the folder which is just the weather data, in my case it's the root of the web server /var/www/html but in your case (and default) may be /var/www/html/weather.

The entry is...

tmpfs /var/www/html tmpfs nodev,nosuid,size=20M 0 0

I gave it 20MB of RAM even though the web server is currently using ~700KB, but I have 1GB of RAM total to play with and will allow for potential expansion. Plus, it's the only thing I have on this particular Pi (Orange Pi PC running Armbian).

Just means, that on boot it can take up to 5 minutes for the web server to be populated with files and will likely return a 403 error when you try to look at it from a browser.

I also created a temporary splash page that just says "loading, please wait." which is loaded by a cron entry on @reboot.

cp /home/pi/temp-splash.html /var/www/html/index.html

Hope this is useful to someone. Has been quite fun to instigate.

-James Muirhead.

[vince]

On Wednesday, July 24, 2019 at 6:55:42 AM UTC-7, James Muirhead wrote

As the web server data is written to the SD every 5 minutes, I felt it would be appropriate to create a RAM disc for it. Should, in theory, improve lifespan of the SD card.

[...]

 

Just means, that on boot it can take up to 5 minutes for the web server to be populated with files and will likely return a 403 error when you try to look at it from a browser.

I also created a temporary splash page that just says "loading, please wait." which is loaded by a cron entry on @reboot.

cp /home/pi/temp-splash.html /var/www/html/index.html

Yes - I think several folks (including me) have posted something similar along the same lines.   I have one pi that I run basically 'everything' in ramdisk, although that of course loses you the syslogs if you need them for forensics after a crash or the like.

One thing you might think about is stashing your NOAA files to disk periodically (couple times a day) and restoring them, as they take a long time to regenerate as you get more and more data.  The other stuff will regenerate quickly on firstboot of course.

[James Muirhead]

Does it not regenerate all of the files on the webserver side every 5 minutes? Or does it only generate the ones it can't find? I got the impression it regenerated everything.

-James Muirhead

[vince]

On Wednesday, July 24, 2019 at 8:06:37 AM UTC-7, James Muirhead wrote:

Does it not regenerate all of the files on the webserver side every 5 minutes? Or does it only generate the ones it can't find? I got the impression it regenerated everything.

The historical NOAA files are a weewx bootup thing only (ie, my previous 12 years of summaries, in my case).

[Thomas Keffer]

Weewx generates any missing NOAA files on every reporting cycle.

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[vince]

On Wednesday, July 24, 2019 at 11:16:48 AM UTC-7, Thomas Keffer wrote:

Weewx generates any missing NOAA files on every reporting cycle.

I did a little test (admittedly a bit contrived) in which I deleted the NOAA file for a month from earlier this year and weewx did 'not' generate the missing intermediate month file. 

[R A Lichtensteiger]

("Long time listener, first time caller")

vince wrote:

> On Wednesday, July 24, 2019 at 6:55:42 AM UTC-7, James Muirhead wrote
>>
>> As the web server data is written to the SD every 5 minutes, I felt it
>> would be appropriate to create a RAM disc for it. Should, in theory,
>> improve lifespan of the SD card.
>> [...]
>

> One thing you might think about is stashing your NOAA files to disk
> periodically (couple times a day) and restoring them, as they take a long
> time to regenerate as you get more and more data. The other stuff will
> regenerate quickly on firstboot of course.

Like many, I stumbled onto the tmpfs ram drive solution a while ago.

Killing three birds with one stone ... I have an init script
(attached) that:

o Backs up the web directory on shutdown or when called with
"sync" or "reload"
o Restores the web directory on startup

Cron entry runs the "sync" nightly, the other two modes are self
explanatory.

R

People using systemd are on their own
--
R A Lichtensteiger

Power corrupts. Absolute power corrupts absolutely. But it rocks
absolutely, too.

[R A Lichtensteiger]

I wrote:

> Killing three birds with one stone ... I have an init script
> (attached) that:

OFFFS ... first post and I screw up by failing to attach the script
<blush>

R
--
R A Lichtensteiger

“Don’t make something unless it is both necessary and useful; but if it is
both necessary and useful, don’t hesitate to make it beautiful.”
—Shaker philosophy