]
Quoted 8 lines · David Woodhouse
Quoted 2 lines · [email protected] said:
Is ext3 already available in beta form? Is it included in the latest
2.3.x kernels?yes, no.
ftp.uk.linux.org:/pub/linux/sct/fs/jfs/ext3-0.0.2c.tar.gz
Thanks for the link. I checked ext3 out. what I found...
1. It is still in pre form. Not too bad, but probably at least 6 months (or more) away from being production quality. Not too big a deal for projects about 1+yr out.
2. This is the big one: It needs 1024 blocks for the journal file. At 1k/block, this translates into 1 meg journal file. This could be a *significant* overhead for small file systems (<10M).
I'm going to download the pre and play with it for a while to get a first hand impression of it. But the 1 meg journal file overhead is too big for medium size embedded systems.
Unfortunately journalling still dosen't solve the problem (that I say first hand) of one entire (512byte) flash block "go bad". The only solution I found to recover this block resulted in the erasure of the ENTIRE block. Now this was at the lowest level (below the file system). I don't know how even a journaled file system would recover stuff (inodes etc.) disappearing from under its feet. Dosen't give me a warm and fuzzy about it.
Quoted 12 lines
Quoted 4 lines
What is the overhead of Journalling? (CPU AND flash space). Of course if that solves the problem, then that is the most important thing (for me at least).
I don't know - I haven't looked into it much yet.
Quoted 3 lines · [email protected] said:
One dosen't have to write to the flash every second, even if logs are being generated that fast. You can accumulate writes in RAM (even backud up RAM), and then archive them to FLASH every 5 minutes etc.
Quoted 5 lines
Quoted 2 lines · [email protected] said:
When I write a log, I want it written and saved. I guess one could do
sync()etc. every time but not very elegant.Err... which do you want? You can't have both.
LOL :) Actually what I meant was that in the write to RAM and then in batch mode save to FLASH situation, I meant that when I want to store the "batch" of logs accumulated in RAM to FLASH I want the thing "done!" rather than "hang around" in VFS buffers etc.
Quoted 3 lines
--
dwmw2
To unsubscribe, send "unsubscribe mtd" to [email protected]