UFS Subdirectory limit.

[Poul-Henning Kamp]

In message <20050326213048.GA33703 at VARK.MIT.EDU>, David Schultz writes:
>On Fri, Mar 25, 2005, Scott Long wrote:
>> David Schultz wrote:
>> >On Sat, Mar 26, 2005, David Malone wrote:
>> >
>> >>There was a discussion on comp.unix.bsd.freebsd.misc about two weeks
>> >>ago, where someone had an application that used about 150K
>> >>subdirectories of a single directory. They wanted to move this
>> >>application to FreeBSD, but discovered that UFS is limited to 32K
>> >>subdirectories, because UFS's link count field is a signed 16 bit
>> >>quantity. Rewriting the application wasn't an option for them.

Has anybody here wondered how much searching a 150K directory would
suck performance wise ?

I realize that with dir-hashing and vfs-cache it is not as bad as it
used to be, but I still think it will be unpleasant performance wise.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.