On Tue, Apr 12, 2011 at 11:34 AM, Ed Flecko <[email protected]> wrote:
> When reading posts about setting up a Soekris using a compact flash, I > see a lot of people saying that a compact flash cannot withstand a lot > of writing before failing. > > 1.) Is that true? How much is "a lot" of writing? (My 4501 is for my > tiny, home network) AFAIK on the order of 100 000 writes to a given block (maybe 4 kB, maybe 64 kB). A good controller does wear-leveling, so the amount of (small) writes a flash as a whole can sustain is actually several orders of magnitude higher. Mount your filesystems noatime, use a reputable flash vendor and a CF a bit larger than you actually need and if possible tune the filesystem not to write everything immediately so it has a chance to catch more changes to a single page (/proc/sys/vm/dirty_expire_centisecs for Linux - see e.g. http://www.cyrius.com/debian/nslu2/linux-on-flash.html - no idea what *BSD has to offer here). No need to use memory fs tricks - actually this is more interesting for harddisks and loads allowing them to stop and save power when there is nothing to do. For a tiny home network you can probably get away with no tweaking at all. A small write each second translates to ~30 millions of writes yearly. A 128 MB flash probably contains at least 2000 adressable blocks, so you are good for some 7 years. -- Stano _______________________________________________ Soekris-tech mailing list [email protected] http://lists.soekris.com/mailman/listinfo/soekris-tech
