On 06/01/15 11:32, Philip wrote: > The 4G CF card that I use to boot my MiniITX server died over Christmas. > I pulled out the card, repartitioned and formatted it and tested it with > F3write/F3read and most of the card appears to be unusable. > This server is (was) running Debian with the CF card in an IDE adapter. > > I am now worried that my Soekris could go the same way. That machine is > net5501 running FreeBSD. > > Is there any early warning that I can get of CF card failure? Are there > any long life cards that are suitable for a general purpose OS. > Should I just forget about CF cards and just boot a normal drive?
I am by no means a specialist but I do have some knowledge based on the following: - I have several Soekris devices that boot a regular OS (Ubuntu and Debian) from CompactFlash, using a regular filesystem (ext4); - the company I work for uses CompactFlash cards in embedded systems where CF is the only non-volatile storage. In neither case is CF wearout a problem. A few points to consider: - Flash memory does indeed suffer from a limitation in the number of block erase cycles it can withstand before becoming unreliable. The use of wear leveling spreads out the erase cycles across the cells in the device as evenly as possible, such that failure occurs catastrophically when it finally happens after the "erase budget" has been used up. - I am not aware of a standardised way of asking a CF device how close it is to wearout. - There are several strategies for avoiding writes to the CF device, including: -- Mount the filesystem with the noatime and nodiratime options. -- Don't log to the CF device but rather to a syslog server on your LAN. If you want to avoid even the minimal syslog reconfiguration that this requires you can use NFS to mount a remote directory to /var/log -- This is not a write-avoidance technique but it also helps to (significantly) overdimension your CF device, then to use only a small partition on it, leaving the rest of the device unused (i.e. unpartitioned/unformatted). This provides more space for the wear levelling algorithm to do its thing. HTH, Jan _______________________________________________ Soekris-tech mailing list [email protected] http://lists.soekris.com/mailman/listinfo/soekris-tech
