QUOTE(ioi84 @ Jun 13 2013, 11:15 PM)
Hi sifus.
I'm a new user of this interesting router. (MR3420 v2 + E398)
So, I need help from sifus here.
Is it normal after I flashed to latest Huntsman, my router will only got 27% space left?
ROOter firmware packs everything in the 4MB flash memory so that users need no extra hard works in order to use high speed 3G/4G internet out-of-the-box. Or, you can flash the vanilla OpenWRT image, which left users with over 1MB+ space on the JFFS2 partition, but require some hard works on the users' side, in order to get it working. Your choice.
QUOTE(ioi84 @ Jun 14 2013, 03:16 PM)
Hi.
I'm using latest Huntsman and noticed that under Software, free space reduced from time to time without changing any setting.
What's the problem?
QUOTE(ioi84 @ Jun 14 2013, 04:07 PM)
FYI, I didn't touch any advance setting or modified anything yet (n00b user)
QUOTE(ioi84 @ Jun 14 2013, 09:36 PM)
After shutting down router for a while (after on for 2 days), looks like free space increase back to default.
Nice observation!
I think this could be due to how
wear leveling,
journaling and compression in actions on the
JFFS2 file system, where OpenWRT Linux writes its configuration data on (/etc/config).
The
Flash Memory used on the router is a kind of
Memory Technology Device (MTD), which is a totally different beasts than the traditional magnetic storage we're familiar with. It has limited write cycles (usually a few thousand to 10,000+ writes per block). It requires special file system support in order to use it efficiently, and also to extend it's working life-span.
When users "save" their "settings", configuration data is written to the JFFS2 partition, where "old" data is deleted, and "new" data is written to different blocks. The "deleted" blocks are not actually deleted but being marked as "invalid". That's why users will see a decrease in space over time, due to wear leveling and journaling. But after a reboot, the space is claimed back, where some "recycling" mechanism kicks in.
I'm no Linux guru though. This is just my hypothesis based on my understanding of information on the Internet. Correct me if I'm wrong.