Monday September 05, 2005 Weblog
Monday September 05, 2005 my experiments with reiserfs - part1
As I don't have a spare disk on my system, I decided to create reiserfs on a 64Mb USB memory stick.
As I have had prior exposure to solaris-ufs, I thought, having a journal or not is a mount time option. But it turned out that, whether I eventually mount it with log or nolog, mkreiserfs sets aside space for log. So with default journal size, I was left with less than 50% of the stick capacity for my use. I thought this is too much and then re-read the man page, and figured there is this '-s' option which sets journal size. So I recreated the FS with '-s 513' (as per the man page min is 513), but this time mount fails to mount the stick saying its not 'reiserfs' partition; which has come as a surprise
as mkreisefs didn't complain at the time of FS creation.
I would have loved to see an option to mkreiserfs to avoid journal. This could have been small disk friendly...
So I didn't have a choice but to settle with less than 50% of disk space for my files.
debugreiserfs(1) is a definite hackers love. Very nice command if you are curious about where (to the granularity of 'byte') exactly is data/metadata.
As the disk space left is very less, reiserfs didn't bother to use internal nodes to store the tree. root block itself is a leaf node, where the directory entries and stat data is available. Whereas I wanted to see the 'formatted internal nodes' in action as I populate the FS.
Looks like my only choice is to get a bigger stick!!! or are there any work arounds ??
( Sep 05 2005, 05:21:44 AM PDT ) Permalink Comments [2]
Trackback URL: http://blogs.sun.com/sprakki/entry/my_experiments_with_reiserfs_part1
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You should *never* use a journaling filesystem on flash media. The repeated writes to the journal will rapidly erode the flash. Reiserfs, like the other core filesystems in the kernel, was designed for "hard drives" which broadly means devices characterized by:
- Large capacities
- High latencies ("seek" times)
- High transfer rates
Your memory stick breaks literally every one of these assumptions. If you want to put a filesystem on flash, there are better choices available. FAT isn't great, but is commonly used and well optimized. JFFS2 is currently the fanciest choice for linux users.If you want to try out reiserfs, do it on a drive partition.
Posted by 66.93.174.199 on September 09, 2005 at 08:30 AM PDT #
Posted by fdasfdsa on October 11, 2006 at 06:43 PM PDT #