newbie: premium with USB flash key, how much flash can I use to add programs etc

I've managed to install the Olegs firmware on Premium.

My goals are: I'd like to use my Premium as the 100% silent, low power, always-on "home access server AND wireless router", to give me the point to which I connect from anywhere and be able to "wake on lan" my other computers, when needed and access them over the vpn.

Questions:

1)

It looks to me that the Oleg's firmware for more or less all Asuses is of the same size, and that Premium has twice as much flash capacity? Does it mean that it would be possible to add a lot of programs to the flash on the device? Do I have to build my whole firmware package for that? What does "flashfs save" do? Does it save only some conf or is it a simple way to add the whole programs to the flash? How can I know how much space on the device I have remaining? I'm sory if there are any texts on this subject, I was not able to find, but I'd be happy to read everything relevant.

2)

I managed to use 2 GB USB flash key instead of the real hard disk. Formatted etc. Now since I've heard about the limited rewrite rates of flashses, can I survive without the swap file if I don't use torrent things, but use openvpn and wireless router functionality?

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All answers and suggestions are welcome. Thanks in advance to all wo respond, and thanks a lot to Oleg for all his work.

It looks to me that the Oleg's firmware for more or less all Asuses is of the same size, and that Premium has twice as much flash capacity? Does it mean that it would be possible to add a lot of programs to the flash on the device?

yes Premium has 4Mb+64kb available for user

Do I have to build my whole firmware package for that?

no

What does "flashfs save" do? Does it save only some conf or is it a simple way to add the whole programs to the flash?

in combination with flashfs commit it saves content of /usr/local and the files mentioned in /usr/local/.files in the internal router's flash

How can I know how much space on the device I have remaining?

When you execute flashfs save the tar.gz file is created and it's size is shown to you. This is how much space it will occupy in flash

2) my answer is possibly yes, try

However, remember, that if you put let say 4Mb in flashfs, then after startup they will be taken out of it, extracted from tar.gz and placed in ramfs. And it will occupy considerably more space in ram than 4Mb. So the more you save in flashfs, the less free ram you have. In conjunction with your desire to use it without flash the real probability of success gets lower.

Quote:

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Originally Posted by al37919

yes Premium has 4Mb+64kb available for user

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Are you sure ?
Mine is 8/32 Mb

Max

I meant that 4Mb-64kb is occupied by rootfs, boot-loader, nvram etc. The rest of 8Mb is flashfs which is available for user

al37919, thanks a lot! I think I see much more clearly now! So if I correctly understand:

- rootfs is the most of 4 MB, and is not copied to ram?
- flashfs is stored in flash as tar.gz and is expanded and copied to ramfs at bootup?

Can the rootfs content be bigger than 4 MB? Is then the best theoretical way to add functionality adding additional programs into that what goes to the rootfs? Is that worth the effort at all, considering new releases that can/will come?

Is then the second best and the most practical way of adding functionality installing the programs on the USB disk? Then no copying to the ramfs occurs?

Is the access to the USB disk already optimized for the flash disks (i.e. no writing of each access time of the file etc) or would I have to work on that? Is there anything else I have to know / take care of?

Thanks a lot!

- rootfs is the most of 4 MB, and is not copied to ram?

yes. It uses so called squashfs which provides access to its (btw compressed) content while uncompressing-on-the-fly

- flashfs is stored in flash as tar.gz and is expanded and copied to ramfs at bootup?

yes

Can the rootfs content be bigger than 4 MB?

hm... IMHO yes. IMHO it's Oleg's decision that he provides a single firmware for wide range of devices, while not utilizing doubled space available on some of them.

Is then the best theoretical way to add functionality adding additional programs into that what goes to the rootfs?

yes, build your own firmware and repartition flash memory in it. However, the last task requires more understanding than just ability to compile something.

Is that worth the effort at all, considering new releases that can/will come?

IMHO no (too complicated). However, the current situation seems to stay in future in Oleg's fws. May be someone else will contribute, but you know it is also a question of trust:)

Is then the second best and the most practical way of adding functionality installing the programs on the USB disk? Then no copying to the ramfs occurs?

Sure. Thinking about filling of the flashfs worthwhile only in the event you want to build a completely diskless system

Is the access to the USB disk already optimized for the flash disks (i.e. no writing of each access time of the file etc) or would I have to work on that? Is there anything else I have to know / take care of?

Who knows... may be Oleg ;)