Sincere thanks for the advice from the following :
- Jean-Loup Risler
- Pat Wilson
- Alan, (alan_at_nabeth.cxo.dec.com)
- and especially Tom Webster for excellent advice
accompanied by very informative explanations.
The replies are appended below but my conclusions are :
1. Start again and put 200 MB for the /
(it's better to start off right while I can make changes)
2. Since we're using UFS, I'll look into setting the inodes
as Tom mentions.
3. Mount the mail partitionas /var/imap (as suggested by those
who said to mount the /var/mail separately).
I erred in the original post and referred to /var/mail.
In fact, we use Cyrus IMAP server.
On this note, Tom pointed out the way that mail produces
one spool file per user. Cyrus supposedly uses a better
method. (folders/subfolders and individual messages - some
call it 'blackbox' approach).
4. Since I do have 4 GB on the HD pretty much sat idle apart
form logs, I'm considering the splitting of /usr/local and
/var also mentioned below.
Thank you once again to one and all,
chas
paw_at_northstar.dartmouth.edu wrote:
>I don't think I'd do it that way - experience has taught me that
>leaving some space unallocated on big disks comes in handy later
>on (when someone decides you need to do one more thing on the
>machine :-O). I'd probably at least put /var/mail in its own
>(huge) partition separate from /data and /var - that way, runaway
>/var/adm logs won't interfere, nor will anything else that might
>wind up in /data. This would also allow you to use disk quotas
>on the mail directory, which might come in handy eventually.
>
>Pat Wilson
At 04:12 PM 5/24/98 -0600, alan_at_nabeth.cxo.dec.com wrote:
>
> I would bypass the step of making /var a link to the
> new partition and just make the new partition /var.
> That will require changing /usr/var to a link to
> /var, but that's what the installation does when you
> chose for /var to be separate.
>
At 11:42 AM 5/25/98 +0200, Jean-Loup Risler wrote:
>> / 100 MB
>> /usr 3600 MB
>> /var -> /data/var
>> /swap 500 MB
>> /data 25000 MB
>
> I would definitely take more than 100 Mb for /
> since DU is growing fast.... say 150 Mb
Tom Webster <webster_at_ssdpdc.lgb.cal.boeing.com>
>Just a couple of comments since the configuration sounds flexable at the
>moment:
>
>1. Consider LSM mirroring or hardware mirroring the boot disks.
>
>2. The root partition looks a little small, I'd be more comfortable with
> 150-200mb.
>
>3. Your /usr partition is large, but then I tend to split /usr/local
> (or /usr/opt if you come from an HP background) and /var off onto
> seperate partitions. In a configuration/security sensitive environment
> this allows you to mount /usr as read-only (make sure that the links
> to var are in place for directories that need to change) and only mounted
> read-write when the OS is updated. 1GB should be plenty if you split
> out your local and var files.
>
>4. As above, I tend to seperate out /usr/local and /var
>
> a. /usr/local is nice to have seperate, just because I don't trust the
> vendor's installers -- that way you can unmount it before any upgrades.
>
> b. /var is nice to have on a seperate partition because it contains both
> your log files and your crash dumps. If your system is attacked, both
> can start to fill a filesystem quickly.
>
>5. If the 25GB raid set is to be used only for the mail spool, why
> not just mount it as /var/spool/mail or to be more flexable,
> /var/spool?
>
>> Are there any speed (I/O) considerations that would
>> suggest an alternative configuration ? (backup/redundancy
>> should be failsafe since it's hardware RAID)
>
>Speed-wise, if you could get another disk I'd strongly suggest using
>RAID 0+1 (somtimes refered to as RAID 10). RAID 5 and especially
>RAID 3 tend to bottle-neck with many small files. RAID 0+1 is a
>stripe set that is then mirrored by an identical stripe set. It has
>the all of the performance benifits of stripe sets and mirroring
>(round-robin reads) but is very costly in terms of disks (2 X capacity
>is needed). If possible, spread all of the disks out over controller
>chanels (HSZ) or at least put the stripe sets on different chanels
>(SWXCR).
>
>Mail, as opposed to news, generates one spool file per user. Depending
>on the number of users, you may want to consider adjusting the inode
>or extent ratio that you use.
>
>I don't remember the max size for a UFS partiion, but if you are using
>UFS -- don't forget to set the inodes per kb down to one or two. This
>will reduce the avialable space bya small amount but will let you handle
>more small files.
>
>A similar caveat goes for ADVFS prior to 4.0D, look at the mkfdmn(8)
>man page for information on increasing the number of extents used.
>
>Older versions of ADVFS have problems with thousands of files being in
>a single directory. I know there is suppoded to be a patch out for
>4.0D, but I don't know if it has flowed back into the patch kits for
>the older versions.
>
>Hope this helps,
>
>Tom
>--
>+-----------------------------------+---------------------------------+
>| Tom Webster | "Funny, I've never seen it |
>| SysAdmin MDA-SSD ISS-IS-HB-S&O | do THAT before...." |
>| webster_at_ssdpdc.lgb.cal.boeing.com | - Any user support person |
>+-----------------------------------+---------------------------------+
>| Unless clearly stated otherwise, all opinions are my own. |
>+---------------------------------------------------------------------+
---------- original question -------------
I'm setting up a new mailserver and seek confirmation
on how I intend to partition a new 25GB (3-disk RAID):
[current configuration]
/ 100 MB
/usr 3600 MB
/var -> /usr/var
/swap 500 MB
Since the additional 25GB will be used for users'
mail and nothing else, it seems natural to just make
one big partition :
[proposed config]
ie.
/ 100 MB
/usr 3600 MB
/var -> /data/var
/swap 500 MB
/data 25000 MB
This is easy for mail to be delivered to /var/mail and,
just like the school of thought that makes /var a symlink
to /usr/var (since disk usage is unpredictable), I will
use all space available.
Does this sound OK ?
(apologies for seeking confirmation of this kind - I
just know it will be easier to sort out now than after
I move all the users over and have never had to deal
with such amounts of space before).
Are there any speed (I/O) considerations that would
suggest an alternative configuration ? (backup/redundancy
should be failsafe since it's hardware RAID)
thank you in advance,
chas
Received on Mon May 25 1998 - 13:08:23 NZST