Messages in this thread | ![/](/images/icornerl.gif) | | Date | Tue, 9 Sep 2003 12:10:44 -0700 | From | Mike Fedyk <> | Subject | Re: First impressions of reiserfs4 |
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On Tue, Sep 09, 2003 at 11:04:21AM +0400, Oleg Drokin wrote: > Hello! > > On Mon, Sep 08, 2003 at 03:24:57PM -0700, Mike Fedyk wrote: > > > You only can have as many inodes as number of blocks on the fs (at least that's the limit imposed on you > > > by mke2fs). > > True, but not exactly. Each file will need one block to store even one byte > > on ext2/3. But your inode tables have about 1/4-1/2 the number of inode entries to > > blocks. This can be changed at mkfs time though. > > Yes, I know this.
I figured you did, as the explanation was mostly for people who don't.
> But my experiments quickly shown that if you ask mkfs to create inode tables with > free inodes that exceed blocks count for the device, then mkfs will only create as much free inodes > as there are free blocks on the device (I was needing that when I experimented with 60 millions files > on ext2/reiserfs/xfs and stuff and I only had 20G partition.) >
Hmm, didn't know this, but it makes sence for ext2/3 since they use 1 block per file/directory. It wouldn't do much good to waste more space for inode tables than you could even theoretically use.
> > Hmm, take ext3 with htree, reiser3 & reiser4 (choose the block size 1k, 2k or 4k) with > > reiser4 does not have support for blocksize different from page size for now (sigh, same old problems > we finally solved for reiser3 recently). >
Interesting, somewhere I think I saw that it was using 512 byte blocks, but don't ask me where I saw that or who said it.
> > tail merging off, 1k files per directory and all files the same size as > > block size with 40M files. How would the table look as far as space effency > > Hm. I will probably try this once. > For reiserfs: > I can tell you that 60M+ empty files (cannot remember exact number, but I still have the script to create those) > took ~5.5G of space.
With how many directories? Do you run into drive speed limitations with that much meta-data, or are there still bottlenecks in the journaling/hashing to deal with? How big are the reiser3/4 equivalents to inodes? In ext2/3 they're currently 128 bytes I believe plus some static bitmaps in the block groups. The only thing variable in ext2/3 are the directory sizes (and they don't shrink... :( )
> Then 60M * 4k is 240G, all these blocks are referenced by leafnodes, ~1000 pointers fits into one node, > so we will spend ~245M for block pointers (extra 5 because there are more layers of indirections). > > > look comparing them? For that matter, how do JFS & XFS compare? > > Unfortunatelly I never had the patience to wait until XFS creates 60M files. Have not tried jfs. >
Hmm, isn't XFS slower than ext2/3 in that regard? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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