10 messages in org.freebsd.freebsd-fsRe: FFS performance for large directo...| From | Sent On | Attachments |
|---|---|---|
| Steve Carlson | Jul 31, 2000 12:32 pm | |
| Zhihui Zhang | Jul 31, 2000 12:44 pm | |
| Alfred Perlstein | Jul 31, 2000 12:46 pm | |
| Terry Lambert | Jul 31, 2000 5:31 pm | |
| Kris Kennaway | Jul 31, 2000 5:45 pm | |
| Zhihui Zhang | Jul 31, 2000 5:46 pm | |
| Terry Lambert | Aug 2, 2000 1:49 pm | |
| Terry Lambert | Aug 2, 2000 1:53 pm | |
| Marius Bendiksen | Aug 2, 2000 2:05 pm | |
| Marius Bendiksen | Aug 2, 2000 2:11 pm |
| Subject: | Re: FFS performance for large directories? | |
|---|---|---|
| From: | Marius Bendiksen (mben...@eunet.no) | |
| Date: | Aug 2, 2000 2:11:15 pm | |
| List: | org.freebsd.freebsd-fs | |
you want. Other solutions exist, such as B*-Tree or Hash table. They will speed up directories look up time.
On a side note, as to B-trees or such, I think this could be done as a hack to UFS, but I'm not very intrigued by the prospect of looking into it, nor the idea of hacking it up even further.
Having said this, you can try to put all directory file into the memory. This is the idea of matt's VMIO directory. You can definitely find discussions on this in the mailing list archive.
This will improve efficiency for situations where you reuse names or at least access stuff in a somewhat non-random manner. You may not want to use this in cases where the expected lifetime of a cache entry is low.
It does not, of course, help the seek issue. Striping your raid array correctly to keep the disks from tending to be bound to eachother would probably alleviate some of the problem, but not much, I think.
A third thing is that FFS performs poor accessing /usr/ports. This has
Actually, it performs poorly on any complex directory hierarchy, especially when traversed depth-first.
something to do with how FFS layout directory inode (not file inode). The
It (IIRC) tries to spread the directory inodes evenly across the cylinder groups, while trying to keep the file inodes in the same cylinder group as the directory inode.
Marius
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