jffs Dangerous??

Discussion in 'DD-WRT Firmware' started by bublik48, Oct 6, 2005.

  1. bublik48

    bublik48 Network Guru Member

    I have read that the usage of the jffs is dangerous. because of the limited ReadWrite cycles of the flash chip.

    is it true???
  2. sade

    sade Network Guru Member

    Probably YAFFS2 could be a better alternative for flash memory ...
  3. littlewhoo

    littlewhoo Network Guru Member

    It depends how often you are writing data to the jffs partition. Depending on the type of flash meomry and the quality it can endure 10.000 - 1.000.000 erase/write cycles (yeah I know, that's a big difference :) ).

    The WRT54G(S) devices use different types of flash chips (Intel, AMD, Motorola...), depending on the hardware revision. Sometimes there are even different flash chips in units with the same hardware revision.

    For example the AMD AM29LV320DB-90EI and the Intel TE28F320 C3 are used in WRT54G units with 4MB flash.

    In new WRT54GS units the Intel E28F640 is being used.

    Afaik all these chips are rated for a minimum of 100.000 erase/write cycles.

    So if you are only sometimes copying some stuff to the jffs partition, there won't be any problems. But if you are running applications, which are constantly writing/deleting data/logs to the jffs partition, the flash memory will probably begin to fail after a few months. In a default installation of DD-WRT (or any other firmware flavour) there is no application that's writing so much data to the jffs partition. But in the Openwrt package repository there are definitely a few applications which will do things, your WRT54G's flash chip certainly won't like, if you install them on the jffs partition. So always check, which kind of data an application is writing to the filesystem, before you install some custom stuff on the jffs partition.

    For example if an application is writing/deleting 10 log entries per minute to/from the jffs partition (certainly not an uncommon figure for apps like syslog), this are > 5.000.000 write/erase actions per year, which will certainly kill your flash memory.
  4. bigjohns

    bigjohns Network Guru Member

    use the samba mount instead...
  5. habskilla

    habskilla Network Guru Member


    I've enabled the samba mount.

    Where should I see it?

  6. bublik48

    bublik48 Network Guru Member

    Well i already know where to find the Samba Settings. I was playing with my wrt54g a lot. I wanted to run the
    WRTbwlog, it's a really nice script. :rockon:
    Then i've read on his Page that it is dangerous to run the script from the jffs because of the read/write Cycles limit. :cry:
    I don't wont to use samba because the my computer has to stay turned on all the day.
    Well it think i will try the SD-Mod :thumb: too bad that i will loose my warranty than.
  7. bigjohns

    bigjohns Network Guru Member

    Sambamount should allow you to share a slice of your computers drive for use as storeage.

    I've not used samba in a while, but I think you can use it to access winNT/Win2k/WinXP as well. These are the items that you configure in the dialog.

  8. imakoki

    imakoki Network Guru Member


    The openwrt package for ddns of no-ip, write more info, and continuously, in de jffs partition? . it can give problems to have installed it? The version of my wrt54g is 2.2. I am asking it reason why she has commented on limits of writings in the flash, and the use of the partition jffs.

    PS: Please, sorry if my english isn`t clear :(

    Thanks ;)
  9. bublik48

    bublik48 Network Guru Member

    Well guys i have tried the SD-MOD and it works!!!
    Now i have a router with 256MB Storage.

    Now i only want to find a way to expand the ram.
    Its a pity the Ram IC's in my router are IC42s16400->8Mb :cry:
    The models that have te IC's IC42S16800->16 they can upgrade to use the full 32Mb ram with some nvram changements.

    I'm thinking aubout to change the RAM IC's or to add another one.
    Ynybody know something about this?? :???:
  10. HarshReality

    HarshReality Network Guru Member

    Old thread I know... does anybody ahve a pinout for the SD Mod on a 2.2 router?
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