Sendmail + IMAP Users = Almost 0 Disk space.

[jpmartins]

Hi all,

I'm a Linux newbie assigned to manage a Fedora 14 IMAP Sendmail server (DELL Power Edge 840). I learn things as I go along and problems show up every now and then, but this one was unexpected: I'm running out of disk space on my IMAP volume... since all my IMAP users don't want to delete old messages, I've run into a big problem.

So my question is: how to add more space to IMAP volume? I've got two possibilities: an old Windows 2000 Server with a lot of free space in it or buying a new USB 2.0 drive with whatever size I manage to find (I have no more space to attach internal drives).

Which one should I use and how to add them to the existing Fedora instalation and also, what are the procedures within Sendmail to move IMAP files for each user to the new volume and how to configure Sendmail to send new mail to those files on the new volume.

I'm sorry for my english if it's not accurate... I'm portuguese and I may not correctly apply the proper definitions. I hope you get the idea of what I wish to accomplish.

Thanks in advance to all that may help me on this endeavor

[Irithori]

hi and welcome,

I am a sysadmin myself and situations like these are not uncommon.
Basically:
"Just make it work, I don´t care how as long as it doesnt cost anything"

The trick is to involve people by offering options.

1) USB drive is not an option.
It is a severe decrease in hardware quality in contrast to your tier 1 hardware now.
Think:
- support contract
- harddisc quality (server discs against soho disc)
- no raid
- latency and performance
- usb vs internal harddisc connection for a email storage? This is not even a question.

2) migration to the win2000 server hardware
Possible if:
- the hardware still works
- hardware support can be guaranteed/extended
- performance is presumably enough

3) Enforce quotas.
Without new server hardware or reuse of 2): Users *need* to delete mails

4) get new server hardware
- Either a external storage to your poweredge 840
- or a new server with enough space


So my suggestion is to write an mail to management/interested parties
- explaining the situation (emails are important data, base of our business, etc)
- explaining the options
- giving a rough estimate of costs/time for each
Offer a meeting for detailed explanation.

Why this way?
Because, if you silently "make it work" with some crappy usb drive and the disc fails,
- And yes, it will -
then guess, who will be the one to blame?

Also, as a professional, you of course head for professional solutions.
These need resources:
- hardware
- people
- time
- knowledge


Worst case:
- The meeting ended and it was decided to go with the usb drive.
- Then make sure you have a email about that decision.
If you have to, write it yourself as a summary and send it to the interested parties.

If the mailserver then fails, point to the mail (maybe print this one ): "I had a better solution, but against my technical suggestion the decision was made. etcetc"
In short: You are off the hook.

[jpmartins]

hi and welcome,

I am a sysadmin myself and situations like these are not uncommon.
Basically:
"Just make it work, I don´t care how as long as it doesnt cost anything"

The trick is to involve people by offering options.

1) USB drive is not an option.
It is a severe decrease in hardware quality in contrast to your tier 1 hardware now.
Think:
- support contract
- harddisc quality (server discs against soho disc)
- no raid
- latency and performance
- usb vs internal harddisc connection for a email storage? This is not even a question.

2) migration to the win2000 server hardware
Possible if:
- the hardware still works
- hardware support can be guaranteed/extended
- performance is presumably enough

3) Enforce quotas.
Without new server hardware or reuse of 2): Users *need* to delete mails

4) get new server hardware
- Either a external storage to your poweredge 840
- or a new server with enough space


So my suggestion is to write an mail to management/interested parties
- explaining the situation (emails are important data, base of our business, etc)
- explaining the options
- giving a rough estimate of costs/time for each
Offer a meeting for detailed explanation.

Why this way?
Because, if you silently "make it work" with some crappy usb drive and the disc fails,
- And yes, it will -
then guess, who will be the one to blame?

Also, as a professional, you of course head for professional solutions.
These need resources:
- hardware
- people
- time
- knowledge


Worst case:
- The meeting ended and it was decided to go with the usb drive.
- Then make sure you have a email about that decision.
If you have to, write it yourself as a summary and send it to the interested parties.

If the mailserver then fails, point to the mail (maybe print this one ): "I had a better solution, but against my technical suggestion the decision was made. etcetc"
In short: You are off the hook.

Hi Irithori,

Thank you for replying so fast. I understand everything you wrote and will make arrangements to get me "off the hook" as soon as I can schedule a meeting with all interested parties.

Meanwhile, can I ask if an exterior mounted (mapped) NTFS partition (within Windows 2000 Server) can do the trick to buy me some time? Does it have to be formated with NFS or can it continue with NTFS (this is probably a terribly stupid question but this is the only way to get answers)? I have a gigabit network and gigabit network cards on both servers. Is this enough for establishing a link between these two servers and serve 66 IMAP users with an email load of at least 7.000 emails daily?

Please tell me I can do this I've got no one else to rely on and no more hardware to quickly apply on this issue.

Thanks once again,
---
João Paulo Martins

[jpmartins]

Please anyone? I see a lot of people reading my message but no one else besides Irithori wrote anything and tried to develop on this issue. Can anyone else help me on this, please?

[atreyu]

Yes, you can access the Windows 2000 Server filesystem as a Samba/CIFS share. You would do something like:

mount -t cifs //<WINDOWS_IPADDRESS>/<SHARE_NAME> /mnt/windows -o username=<WINDOWS_USERNAME>

You'll likely need to pass the mount command other options, in order to play nice with the NTFS filesystem (uid, umask, etc. - look them up).

However, I highly agree w/Irithori - you should reinstall that Windows server as a Linux server.

BTW, NFS is not a filesystem itself - you would not format a drive with NFS. It is rather a means of sharing a (typically) UNIX/Linux native filesytem over a network. This is not an (easy) option in your case.

Also, is it an option to borrow a hard drive from the Windows machine and stick it in the Linux server - as a temporary fix, as you put it?

This whole thing is screaming "backups", too. Given the situation you described, it sounds like those are not happening yet. Put that next on your list.

[jpmartins]

Yes, you can access the Windows 2000 Server filesystem as a Samba/CIFS share. You would do something like:

mount -t cifs //<WINDOWS_IPADDRESS>/<SHARE_NAME> /mnt/windows -o username=<WINDOWS_USERNAME>

You'll likely need to pass the mount command other options, in order to play nice with the NTFS filesystem (uid, umask, etc. - look them up).

However, I highly agree w/Irithori - you should reinstall that Windows server as a Linux server.

BTW, NFS is not a filesystem itself - you would not format a drive with NFS. It is rather a means of sharing a (typically) UNIX/Linux native filesytem over a network. This is not an (easy) option in your case.

Also, is it an option to borrow a hard drive from the Windows machine and stick it in the Linux server - as a temporary fix, as you put it?

This whole thing is screaming "backups", too. Given the situation you described, it sounds like those are not happening yet. Put that next on your list.

Thanks so much Atreyu,

Now I have a different perspective on the issue... I'm a lot calmer knowing that I can connect both Linux and Windows file systems if I need to, at this level. Yes, reinstalling Windows 2000 Server machine as a Linux Server is an option I already thought doing, but not borrowing a disk from Windows Server because my Dell disk cage is already full. So I thought about formating this old server with the same Fedora version and connect both, via network cable since I have a gigabit network. You guys think that this is enough and also a good idea?

Regarding backups, I've done that since day one on my new assignment to an existing exterior HP RDX 250 GB cartridge system (never tested to see if all is well even though I can see all IMAP user files inside the 5 cartridge daily cycle.

Also, thanks so much to clarify things for me regarding NFS... I really thought that was a Linux File System (can you point a really good Linux course for absolute beginners?). I know that there's a lot of stuff on the Internet, but I'd love a structured course like "Linux 101" or something likewise starting from there.

Thanks again for the time you took to answer my newbie questions,
---
João Paulo Martins

P.S.-> Forgot to tell you guys that on Fedora server all administration tasks are made with Webmin and users access their IMAP mailboxes with Usermin.

[Irithori]

I would suggest neither cifs nor nfs.

Cifs has the drawback, that you introduce needless conversion to windows compliance,
when you really need to keep it a unix task.
No need to introduce additional complexity.

nfs for roughly 1 million (index + data per mail) little files a day...
I dont like it.

So if you dont have the time to install linux on that win2000 server hardware and migrate config + data,
then my suggestion for a *quickfix* would be to install FreeNAS 8 on the win2000 server hardware and make it a iSCSI target.
You would then run an iscsi client on your fedora box and mount the remote storage.

Why FreeNAS? Because it is a very quick way to have an (entry) enterprise grade file and storage server.

Why iscsi? Because it is imho faster and more reliable than nfs. Also, you dont need to share with multiple clients, just one machine.
iSCSI works on the blocklevel, it is not a filesystem. It provides a scsi device over the network.
If you can, make it a dedicated 1GBit/s network between the two machines.

Why QuickFix? Because this solution at least doubles the probability of failure: If one of two servers has a problem, then mail is unavailable.

So if you go for the iSCSI approach then make it very clear, that this is temporary and you still need new and appropiate hardware.


P.S.: While iscsi is not too complicated to understand, I somehow doubt that webmin will be of much help.
How are your commandline skills?

[jpmartins]

I would suggest neither cifs nor nfs.

Cifs has the drawback, that you introduce needless conversion to windows compliance,
when you really need to keep it a unix task.
No need to introduce additional complexity.

nfs for roughly 1 million (index + data per mail) little files a day...
I dont like it.

So if you dont have the time to install linux on that win2000 server hardware and migrate config + data,
then my suggestion for a *quickfix* would be to install FreeNAS 8[/URL] on the win2000 server hardware and make it a iSCSI target.
You would then run an iscsi client on your fedora box and mount the remote storage.

Why FreeNAS? Because it is a very quick way to have an (entry) enterprise grade file and storage server.

Why iscsi? Because it is imho faster and more reliable than nfs. Also, you dont need to share with multiple clients, just one machine.
iSCSI works on the blocklevel, it is not a filesystem. It provides a scsi device over the network.
If you can, make it a dedicated 1GBit/s network between the two machines.

Why QuickFix? Because this solution at least doubles the probability of failure: If one of two servers has a problem, then mail is unavailable.

So if you go for the iSCSI approach then make it very clear, that this is temporary and you still need new and appropiate hardware.


P.S.: While iscsi is not too complicated to understand, I somehow doubt that webmin will be of much help.
How are your commandline skills?

Well my command line skills aren't like yours of course, but I can do some stuff... I can understand commands and switches and a bunch of other things that I learned since I was assigned for this job.

I'm a fast learner and I read a lot of Linux documents trying to get a grip of all this... but since all my learning is disconnected from the problems that every now and then happen, I'm always fearing to do something wrong. I sweat a lot when I have to make any critical change within Webmin or console.

So tell me what you got concerning command line and let's do this That one idea about FreeNAS was amazing I loved it. Never thought about it but it could really work until I get the approval to buy a new server.

You're the man

[jpmartins]

Well my command line skills aren't like yours of course, but I can do some stuff... I can understand commands and switches and a bunch of other things that I learned since I was assigned for this job.

I'm a fast learner and I read a lot of Linux documents trying to get a grip of all this... but since all my learning is disconnected from the problems that every now and then happen, I'm always fearing to do something wrong. I sweat a lot when I have to make any critical change within Webmin or console.

So tell me what you got concerning command line and let's do this That one idea about FreeNAS was amazing I loved it. Never thought about it but it could really work until I get the approval to buy a new server.

You're the man

Ok I've downloaded and created a CD with FreeNAS image and then I went through the manual, but didn't see how to install it within Windows or any other OS. Just some screens on how to install it booting from CD... isn't that going to overwrite Windows instalation? Is this the right way to go?

Please enlighten me...

[Irithori]

FreeNAS is based on FreeBSD, an operating system.
So yes, this will replace windows and delete any data on that box.
I understood, that this machine is free to use?

You need at least two drives.
One with 4gbytes or more to install this operating system
and another which holds the data.

At home I installed it on a usb stick, in your case it might be better to have it on internal disks of that win2000 server hardware.
A small raid1 setup maybe.