Where does flash become a part of the RouterOS? And why is it sucking the life out of a RB750G Hotspot?
Users on the hotspot?

oooo, i wonder if thats IO Wait ...

It's not Adobe Flash... It's flash storage. And yes, writing to it uses a lot of CPU.

How does it come you have so many flash NAND access?
I tried to reduce NAND write to a minimum level on my own 450G (though no hotspot).

He is probably using the transparent proxy feature of the Hotspot to get the web proxy involved. 750s have tiny amounts of storage so the cache is constantly being thrown out and replaced with new file objects.

Yes,
I'm using the transparent proxy. I understand it consumes memory, but what's the alternative?
No trans proxy and and the router is crippled isn't it?

Add: If you notice the errors from radius in log.

Radius accounting request not sent no response.
Does that error/log correlate with the excessive flash overhead?

FYI, I had a few unneeded firewall rules which i've deleted. And I was not using 127.0.0.1 in radius config or in hotspot server profile. Both were pointing to my public domain, and that config seemed to be ok. But, I can see now why that's unnecessary.

Since cleaning up firewall rules and radius config, no recurrence of the flash issue. But, I'm waiting to see if the radius accounting request issue pops up again.
Thanks

Don't proxy. A 750G makes a very, very poor proxy. You're not getting much out of it anyway - the storage available is so small hardly anything is being served from storage, but it keeps being rewritten with new objects. Turn it off, and you should be fine.

Great, I'll eliminate it.

hello,
i've got same problem on my rb133... but i've got everything disabled except minimum functionality...
what is going on ?

same problem, disable proxy

proxy is disabled, whoever i've got web-proxy in stores and i cant delete it..
shortly after reboot it is disabled and i can remove it but after few seconds entry is back and active

create a new store, set it as active, then remove the old (full) store.

ok 've deleted this unused store by creating new one that i also cant remove

why is this happening ?
this rb is working only as AP Bridge

do you use hotspot?

in first screen i've show enabled packages, Hot-Spot is disabled and unused on this device (also on GW if you ask)
routing, dhcp etc is disabled
i'm using only wireless and bridge

make a supout.rif file and send to support, we will check what is using the store.

ok, i'll wait until cpu reaches 100% and make supout.rif
or it isnt necessary ?

yes, please wait until cpu is high, then make file

its gonna be a litle bit troublesome...
RB is rebooting when i'm trying make supout.rif when cpu is idle...

i'm suspecting power adapter (12V/1A), it can overheat and shutdown for a while... whatever

when i'll have file i'll send it to support

since i've created new and delete old store for proxy and cpu utilization back to normall
uptime 6d and everything is ok

Looks like this problem persists in RouterOS 5.26 on my routerboard 751U-2HnD. Web-proxy disabled, wireless, ipv6, hotspot, mpls packages are disabled too. There is additional Ntp package working. Using dhcp-server, ntp-server, firewall (filter, NAT, mangle, address-lists), bridges, PPPoE clients, and PPTP server. The problem disappearing sometimes for a few days by itself, but then returned (maybe due to increasing connections count and, thereby, more RAM utilising). Often the CPU becomes so busy that router stops responding at all and needs rebooting. I've set up the watchdog and it helps to do it automatically (thank you for it). But nevertheless the work going bad and interrupted sometimes.
How to really disable the RouterOS web-proxy?
Maybe I have to try to upgrade to RouterOS v6.18?

P.S. Sorry for flood.. Removing the "web-proxy" storage by adding new one helps with sucking CPU by flash, just after rebooting. After rebooting I've removed all storages of web-proxy. Now it works yet... If the flash problem will back again I'll write more..
P.P.S. It has been back again... The problem returns when I give "/system backup> save name=<AName>" and "/>export file=<AName>" commands. I don't know yet which of them really provokes it. But after executing this two commands the "web-proxy" store appeared again, and again it is active... and the "flash" process category started to suck CPU again (sometimes looks like it hushes, and continuing using CPU in a few minutes). I've deleted the store by adding new one (like I had done it first time). I shall try to reproduce it again when it will be safe to reboot my router... or when it will reboot itself.

... I shall try to reproduce it again...

Successfully reproduced. New "web-proxy" store creating when I give command namely when I try to export all the settings to script file.
Hmm... may some contents of the file to provoke this proxy-store-flash problem during export?
P.S. Or... maybe it happens just when I open the proxy settings window in WinBox? I've just looked to it to make sure that the proxy is off... I'll try once again...

... I'll try once again...

Wow.. the "web-proxy" store created and activated in both cases: on all settings export and when I just open /ip/web-proxy settings in WinBox. I triend it on two routers, RB751U-2HnD and RB750GL with RouterOS 5.26. But "flash" uses CPU greatly just on first of them. And I don't know yet if it uses it so high after just opening that settings window... I will look more.. Maybe sometimes the router just having too few RAM (when proxy using it too) and so it uses a swap file? Has RouterOS any swap-files on routerboards?
Sorry for maybe too much waste text.. It seems to be an old issue, but I failed to google a good answer.

I still don't know why my router hangs, I just can say that it can hang with proxy turned off and even with no "stores" at all too. "Flash" process uses CPU highly, mostly under high client load, but the traffic can be little, so I think maybe connection count or DNS cache size is the bottleneck. Sometimes it eats all the CPU time suddenly. I believe the router hangs due to "flash" process, and maybe it affected by lack of free RAM..
by the way.. it has only 32Mb of RAM. And despite of about 10Mb are free most time (it can fall to 5 and ... perhaps it less when I can't see), maybe RouterOS tries to free some amount and flushes some virtual memory to flash?

Finnallllyy some clue here - I have same situation - disabled proxy - and my routerboard hangs after random time -
When it happens "Flash" is rasing and rasing ... is the only option migrating to 6... ?

... is the only option migrating to 6... ?

I don't believe it was really an option (unless Your router has a multikernel CPU: I've heard RouterOS 6 manages kernels more efficiently). I had just asked about it, but can't say definitely or test it in the place where it happened. That router seems to work fine on some smaller loads. Finally I've installed another router with more RAM (old was 32MB), as I have not seen this problem on any 64MB router. After couple weeks I can say the problem successfully solved this way...