[Dxspider-support] RPI 4 settings for reduced writes to SD card

[Michael Walker]

Just to be sure, I did a 'free -m' after I disabled Swap.

Assuming no memory leaks in anything, it will be  a long time before we
consume all MEM.

root at va3mw-cluster:~# free -m
              total        used        free      shared  buff/cache
available
Mem:           3906         181        3428          27         296
 3593
Swap:            99           0          99

I will likely move all the data files over to my ram drive.  I should have
no issue assigning 500M of ram to that drive on a  PI 4.

I did run iotop for about a day it the cluster does write a lot of data in
a 24 hour period.

Anyway, I will monitor it and see how it goes.  If it blows up, it is
pretty trivial to rebuild.

Mike va3mw


On Tue, Mar 31, 2020 at 2:06 PM Matthew Chambers via Dxspider-support <
dxspider-support at tobit.co.uk> wrote:

> Ideally you never want to use swap anyways. I have a full blown Dell
> PowerEdge server running CentOS that I use for my webserver that has swap
> but has yet to ever touch it. My desktop does end up all the using swap
> because of web browser memory leakage and I can tell because everything
> comes to a near halt. Swap usage is slow and inefficient and a sign there
> is something else wrong. I can't imagine DX Spider ever needing that much
> memory that it has to fall into swap usage.
>
> Matthew Chambers, CBT, NR0Q
> Owner/Engineer
> *M Chambers Communications Engineering LLC*
> PO BOX 855, Moberly, MO 65270
> Mobile (660)415-5620
> www.mchambersradio.com
>
>
>
> On Tue, Mar 31, 2020 at 8:03 AM Michael Walker via Dxspider-support <
> dxspider-support at tobit.co.uk> wrote:
>
>> Hi
>>
>> I have had class 10 cards fail in much less than a year on 2 weather
>> stations.  I can't tell you why, but the file system did go read only on
>> each of them.
>>
>> I also routinely turn off the Swap storage if I know that I will never
>> surpass the RAM storage available without issue.  Since my RPI's are built
>> for a single purpose they don't come close to over running maximum RAM.
>>
>> I really don't require the /data directory, so I will move that to a
>> ramdisk.  Should I ever need it, I can turn it back on to debug as
>> required.   I managed to go 5 years without looking at it at all.  :)  The
>> DXSpider code is pretty solid so it is rare it might be needed.
>>
>> I found log2ram some time ago https://github.com/azlux/log2ram and that
>> made it pretty easy to configure.
>>
>> Thanks for the input.  Mike va3mw
>>
>>
>> On Mon, Mar 30, 2020 at 6:55 PM JOSEPH REED <joe at n9jr.com> wrote:
>>
>>> A Class 10 SD card doesn’t fail in 6-9 months, but it will fail.  You
>>> have two USB 3 ports on the Pi 4.  The best and easiest way I know it to
>>> acquire an inexpensive USB SSD drive.  Attach it and clone the SD to the
>>> SSD but with different partition IDs.  Edit /boot/boot.txt and replace the
>>> partition ID of rootfs with the rootfs partition of the SSD.  You will boot
>>> from the SD, but after boot everything is on the SSD.
>>>
>>> And you do not want to turn off swap!
>>>
>>> Joe N9JR
>>>
>>>
>>>
>>> On Mar 30, 2020, at 7:36 AM, Michael Walker via Dxspider-support <
>>> dxspider-support at tobit.co.uk> wrote:
>>>
>>> Hi All
>>>
>>> A few weeks ago I moved my Cluster over to a RPI4 where it hums along
>>> nicely.
>>>
>>> I know from many weather stations that the SD card will go into a read
>>> only state in about 6-9 months as writes start to fail.  Running IOTOP
>>> tells me what we do significant writes to the card.
>>>
>>> Does anyone have a list of things they do to minimize the writes?
>>>
>>> On my list I have:
>>>
>>>
>>>    1. Turn off the swap space
>>>    2. Move /spider/data to a RAM disk
>>>
>>> Anything else?
>>>
>>>
>>> _______________________________________________
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>> Dxspider-support at tobit.co.uk
>> https://mailman.tobit.co.uk/mailman/listinfo/dxspider-support
>>
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