[BradS17601]

I use many static leases. All was fine when I was using about 59 of them. But when I added a 60th one, something went wrong enough that the router stopped handing out DHCP addresses altogether and no wired nor wireless client could use the internet. I'm starting to think there might be a limit that I'm bumping into. I'm thinking this because this is the 2nd different brand of router that I had some similar symptoms. I have more research to do, to determine if this is really the root cause of my problems, but I've not found any information indicating there's a limit. Wondering if anyone else has run into a problem like this.

[Alozaros]

hmmm, i do believe i faced the same problem in the past...
check your NVRAM if it's full you have to move DHCP leases in to a jffs2 (on a flash drive)
Services>DHCP Server>Use JFFS2 for client lease DB


next time not bad to mention first what router and what build you run......

[BradS17601]

OK... your clues certainly are helping... and other searches on the forum are helping too.
FYI: Router is Linksys WRT1900AC version 1

I found this command elsewhere on dd-wrt forums
nvram show >/dev/null
The results are:
size: 29489 bytes (36047 left)
I'm assuming people would call this a 64K router 64*1024=65536
since 29490+36046=65536
And it looks like
I've got plenty of space

So I tried this
nvram show | grep static_leases
static_leases=I get 3207 characters in response representing the 59 Static Leases I typed into the GUI
All looks well.
I can apply/save/reboot and the router hands out a DHCP address to my PC.
But when I add one more
after reboot, my PC gets an autoconfig address 169.xxx.xxx.xxx
If I change my PC to a static address using Windows Control Panel, I can go to the router home screen.
If I remove the 60th Static lease, reboot the router, change my PC to Automatic Addresses, all returns to normal with the Router handing out a DHCP address to my PC
So... I'm starting to think that the length of my static lease string is too long or has hit some limit.

Then... using Alozaros idea:
dd-wrt > Administration > Management > JFFS2 Support
Enable Internal Flash Storage
Enable Clean Internal Flash Storage
Apply > Save > Reboot Router
dd-wrt > Services > DHCP Server > Use JFFS2 for client lease DB
Enable Use JFFS2 for client lease DB
But... I'm out of my league and don't really have any evidence that this did anything yet.
When I run command:
ls -al /jffs
Returns
drwxrwxrwx 4 root root 0 Dec 31 19:00 .
drwxr-xr-x 15 root root 231 May 1 2017 ..
-rw-r--r-- 1 root root 158 Dec 31 19:12 dnsmasq.leases
drwxr-xr-x 3 root root 0 Dec 31 19:00 tmp
This certainly appears that the system didn't automatically move my static leases to dnsmasq.leases

Run Command (I found this somewhere but do not know how to decipher the results)
df -h
Returns:
Filesystem Size Used Available Use% Mounted on
rootfs 24.8M 24.8M 0 100% /
/dev/root 24.8M 24.8M 0 100% /
none 512.0K 0 512.0K 0% /dev
/dev/mtdblock/9 37.0M 1.1M 35.9M 3% /jffs

So I'm not sure where to go from here. I have not found all the steps I need to be successful (and I'm a total noob with Linux)