All, here is my original post:
I know that in some flavors of Unix, when more than 1024 files or
subdirectories are created off of one point, the file system on the
machine slows down. For example: more than 1024 home directories in
/usr/users or many mail spool files in /usr/spool/mail.
Has anyone experienced this sort of condition on a DUX 3.2b machine with
the UFS file system?
And, along the same lines, is there a quick way to get Digital's
sendmail (5.65) to split up it's mail spool directory into several
directories (without putting the mail in the home directories)?
And, here is the responces I got. Thanks to everyone!!
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On Thu, 29 Aug 1996, Richard L Jackson Jr wrote:
acs>>
acs>Yes, this is a problem under UFS and Advfs. I have over 42,000 users.
acs>I had to sub-divide the home area into 5 areas to help reduce the impact.
acs>The problem is very noticeable when NFS used, also.
acs>
acs>--
acs>Regards,
acs>Richard Jackson George Mason University
acs>Computer Systems Senior Engineer UCIS / ISO
acs> Computer Systems Engineering
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On Thu, 29 Aug 1996 alan_at_nabeth.cxo.dec.com wrote:
acs>
acs> Directory lookup may suffer a performance loss on a Berkeley
acs> Fast File System implementation (UFS) when the directory needs
acs> to use indirect blocks to store the locations of the directory
acs> data. On Digital UNIX happens when the size of the directory
acs> file exceeds 96 KB. A directory isn't fixed size, so the number
acs> of files that can fit in 96 KB depends on the length of the
acs> file names. The minimum directory entry is probably 12 bytes
acs> allowing three for a file name, four if the NUL doesn't have
acs> to included.
acs>
acs> For larger names 16 is the minimum since the names are always
acs> padded to four byte boundaries. Assuming all 8 character file
acs> names that 6,144 entries before an indirect block is needed.
acs>
acs> And with a fair amount of data and namei caching, the performance
acs> loss may not be noticable even when a directory gets that large.
acs>
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On Mon, 2 Sep 1996, Lucien HERCAUD wrote:
acs>
acs>Date: Mon, 2 Sep 1996 16:22:53 +0100
acs>From: Lucien HERCAUD <Lucien_HERCAUD_at_paribas.com>
acs>To: "Andrew C. Saylor" <asaylor_at_alpha.comsource.net>
acs>Subject: Re: 1024 File/Directory Tree Limits?
acs>
acs> To make sendmail split:
acs>
acs> One easy solution is to create DIRECTORIES is /var/spool/mail/
acs> for the recipents by using the recipients names. Sendmail will then create
acs> files inside those directories and drop mail inside.
acs>
acs> eg. for user "lucien"
acs>
acs> --> /var/spool/mail/lucien/lucien
acs>
acs> will be the maildrop file.
Received on Wed Sep 04 1996 - 17:20:23 NZST