Am 2005-06-05 16:06:42, schrieb Steve Lamb: > It is not a silly response, it is factual. 500Mb of mail at an average of > 5Kb per message is 100,000 messages. 100,000 files in a single directory is
OK, I have curently around 220.000 MAILDIR-Messages of the LKM in
my Folder on a FileServer which is a Sempron 2200 with 256 MByte.
Open the Folder with mutt takes around 57 seconds via NFS/100MBit
The same as Mailbox will kill the machine because oben a Mailbox
of this dimension require realy much memory and the whole Network
connection is blocked. It need around 8 Minutes to open and
crashed because there is a limit of 2 GByte on i386 Systems.
Please note, that my LKM mailfolder has 220.000 Messages with
around 3200 MByte, which can only be handled bei a real 64Bit
Operating system like amd64 or IA64 (and oterh 64Bit CPU's).
Open the same folder with from 'mutt' with courier-imap requires
around 23 Seconds.
Why is this ?
You have forgotten ONE BIG THING !!!
A MUA which open a Mailbox file, require to read the whole file to
find the BEGIN of the HEADER and its END and then the END of the
BODY. So you wats all your CPU resources looking for data.
In Maildir, the BEGIN of the HEADER is the BEGIN of the FILE and
the MUA skip the rest of teh Messages if it find the END of the
HEADER.
Via IMAP, the MUA sends a request to the IMAP-Server which HEADER
it like and the IMAP-Server send only the required HEADERs to the
MUA. Because the IMAP-Server does not need to annalyse the HEADERs
it filter only the REQUESTED ones and terminate.
In summary: If you have big mailboxes, like mailinglists,
you will go better with Maildir or IMAP
> not "more efficient for individual deletes" when you're a mail administrator
> trying to reduce the mail load so the customer's machine won't time out while
> connecting to the server to retrieve mail. You can't even do simple file
> operations to know which files to delete without the machine taking several
> minutes. Any file globbing is out of the question since it will more than
??? - Mutt uses hashes to find the right one
and do not need to rescan the whole Maildir.
If this is not true, my FileServer should not work
with its Sempron 2200+ and 256 MByte of memory.
> likely exceed the maximum number of arguments and filename completion again
> causes excessive pauses. In short every operation for manipulation the
> messages is just shot to hell.
???
> A comparable mbox, on the other hand, you can at least do all of the above
> without having a book handy. The only operation which takes quite a while
> would be opening up the file in a text editor. Of course that operation is
Opneing a file of 500 MByte as you told before
and the edit by hand ? - Are you dreaming ?
> faster than anything requiring traversing the directory and once open
> operations are far faster.
>
> Maildir is good on paper. In practice and in contact with customers
> maildir falls flat on its face. In the years of admining mbox at an ISP with
> 7,000 customers I never had corruption issues and mail problems like the above
> were resolved in a few minutes. My last job at a smaller hosting company with
Hmmm, I am using Maildir sind my last Windoze is gone, which mean,
since 04/1999 and never had problems with Maildir or lost a message.
You mus do something wrong!
> only hundreds of customers I routinely had to fix maildir's problems and spend
> an ungodly amount of time (30-40m) per problem because I had to work around
> not being able to file glob, do a simple directory listing, etc. I don't
> consider that "silly" in the lest and given the inclination of us unix geeks
> to keep thousands of messages lying around for years on end it is certainly a
> concern that should be passed on to any potential person thinking of maildir.
Quest: Do you backup your System ? - How often ? I do only one
time per week Full-Backup and then 6 Incremental-Backups.
I do not like to think on daily Incremental-Backups of around
50 GByte Mailboxes, because you need to backup ALL changed.
On my Maildirsystem I have only 20 MByte per day.
Greetings
Michelle
--
Linux-User #280138 with the Linux Counter, http://counter.li.org/
Michelle Konzack Apt. 917 ICQ #328449886
50, rue de Soultz MSM LinuxMichi
0033/3/88452356 67100 Strasbourg/France IRC #Debian (irc.icq.com)
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