Re: Writing a GNOME mail client.

[Warren Young <tangent cyberport com>]

Nathan Clegg wrote:
> 
> By giving every message its own file and even splitting a single message
> into several files, don't we risk running out of inodes on a multi-user
> system??  I collect hundreds of messages every week from my 15+ mailing
> lists, compared to the thousands I throw away.  Aren't we also seeing a
> performance hit if we have to open multiple files everytime we scroll to a
> single message, or likewise if we have to read, say, 1000 files to open a
> single folder?

Inodes in Linux are 32 bits long.  If your machine had 1024 users on it,
they would each have to have over 4 million files before they overloaded
an Ext2 filesystem's inode limit.  Before you hit that, you hit other
limits, like the fact that to exhaust the inodes, you'd have to fill a
4TB disk with 1-block files.  (Assumes 1024 bytes per block.  For 4096
byte blocks, you'd need a 16TB disk before you'd hit the wall.)

On a typical system with a 9GB disk for the users and around 1000 users
(~9MB for each user), each user would be able to have about 10,000
files.  That assumes that all files are under 1K each.  If that's not
the case, you'd add another disk (and thus several million more inodes)
before you ran out of inodes.

You may have a valid point, though.  Perhaps it would make sense to pack
all the subfiles I mentioned into a simple, single file, such as a cpio
or ar archive.  The main point is that by logically separating the parts
of the data, it's easier to deal with it and it allows a more flexible
system.
-- 
= Warren -- http://www.cyberport.com/~tangent/
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