Subject: Outlook Express and "Check for Messages in all Folders"

From: "Marc Mason" <[email-masked]>
Date: Thu, 9 Sep 1999 19:18:05 -0400

I am running imapd 4.6 beta on a Sun Enterprise 450 with 4*250MHZ CPU's and
3.5GB's of RAM. The build information is as follows....

* OK crete IMAP4rev1 v12.251 server ready

I am running standard UNIX mailbox format on all user accounts and I am
supporting 1100 corporate users.

I have /var/mail mounted on a Veritas File System running as a  software
RAID 0+1 using Veritas Volume manager with two disks for the stripe set.   I
have a script that puts an IMAP alert on a user's account when the inbox
size is over 10MB's. Performance for the files in the user inboxes is
acceptable.

I have made /tmp a RAID 0, and /var/spool/mqueue is a separate disk.

I am having trouble with the performance of the remaining user folders which
are in their home directories.  Currently the users are on a software RAID-5
consisting of 4 disks.  I clearly have a problem with write saturation as
users are complaining that it takes forever to save mail to their "sent
mail" folder on the server.  I have a limited set of users that either don't
have saving to the "sent mail" folder, or have a home directory on another
disk, and they have not seen the degradation in performance.

I'm planning to regroove the home directories this weekend and create a RAID
0+1 with 4 disks in the stripe set.  I figure that will help overall
performance.

1) Should I use the Veritas File System, or am I better off sticking with
UFS?

2) I have noted that a lot of our users have "Check for Messages in all
Folders" enabled.  Is this option as hard on a server as one might intuit?
This seems to be a Microsoft default.  Either I'm getting cross-eyed or the
daily accounting reports  are showing me that we are transferring 1/2 a
Terabyte a day! Are there any other client-side settings that Microsoft has
set that are really hard on a server? Is the synchronize folders setting
hard on the server.  I notice a smaller number of users have this set.

Load either stays in range or goes right off the charts when we get any kind
of steady inflow of mail to a limited set of user that have procmail set ups
that route the bulk of their mail to their home directory.

I run the "virtual adrian" application and it confirms the disk saturation
as frequently critical.  The application has also complained less frequently
of amber  (warning) level memory shortages and a  couple amber mutex stalls.

I don't want to convert to mbx format unless I have to for a number of
reasons, is there anything else I can do to improve system performance?

Marc Mason  1-301-340-7788 ext. 3448
UNIX Systems Specialist
Phillips Publishing International, INC.
[email-masked]

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