On 8/31/2011 5:06 PM, Michael Torrie wrote: > I'm trying to put together a mini server (almost an embedded system) and > I'm struggling to know what kind of file system to use. Most of the > boards I'm looking at (must be x86) have either compact flash or SD > slot. Given that the computer will run like an embedded system and > could be powered off at any time, I'd like to get a file system on it > that won't wear out the CF, and won't get corrupted with power outages. > For the most part, the server won't do too much disk I/O. There are no > databases, and logging isn't that important. So some of the file system > could be read-only. I need about 1-2 GB (this baby has to run CentOS 5 > or 6 and run data acquisition software written in labview) of storage. > > I've had experience on sheeva plugs running both JFFS2 and UBIFS with > standard debian installs (standard syslog, etc) and they run great, but > both file systems are designed for MTD devices, but both CF and SD are > block-level devices with internal wear-leveling, so neither file system > is appropriate here. Besides that fact, I created a virtual 4 GB (about > the size I need) CF disk and used the block2mtd driver to make it be a > MTD device, and though I can format it with ubiformat, I cannot attach > it. It gives me a kernel memory allocation error. Even 1 GB gives me > this error. I can get a 512 MB image to work, but that's not enough > space for what I need anyway. I know I can do a jffs2 emulation on > compact flash, but the mount time for a large volume is horrendous. > Even 512 MB takes a while to mount. > > So at the moment I'm considering doing read-only ext4 for most of the > partitions, with a small R/W ext4 partition for variable things. But if > anyone has any better ideas or experience in this area, I welcome > suggestions. We had a situation at work where we are working with an embedded linux device and have to use an SD card for the filesystem. After a bunch of benchmarking, we chose ext4 and now have a 32GB class 10 SD card working at about 7-9 MB/s writing (which was our only concern. Reading can go slower than 2MB/s for all we care, but I'm pretty sure its performance is equally good.)
The trick was we had to disable extents, and possibly play with the block size, but I don't recall on the latter. YMMV, but I think you'll like ext4's performance. -Tod Hansmann /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
