Topic: Building New Server

[marietta]

I am building a new SME mail server. I have a few questions:

Here is what I am looking at :
2 - 2.0GHZ Quad Core processors
4GB of RAM
3 160 Hard Drives with Raid 5

I have about 2000 email accounts.

Is this overkill?

SME will read 3GB of RAM per processor since they are quad core will it read 12 GB per processor? Should I go more RAM?

My old mail server has 2 single core processors, 2 GB of RAM and 2 mirrored 36GB Hard Drives. Should I go with mirrored or RAID 5? If Raid 5 should I make it Raid 5 + 1?

Any help is greatly appreciated!

[David Harper]

Welcome to the forums

Is this overkill?

I think the specs you posted are pretty reasonable given the number of email accounts.

SME will read 3GB of RAM per processor since they are quad core will it read 12 GB per processor? Should I go more RAM?

I'm pretty sure that the "hugemem" SMP kernel will support upwards of 16Gb of RAM. For that many users, I would definitely suggest a lot more memory if there are going to be a lot of users accessing their email simultaneously.

My old mail server has 2 single core processors, 2 GB of RAM and 2 mirrored 36GB Hard Drives. Should I go with mirrored or RAID 5? If Raid 5 should I make it Raid 5 + 1?

With an install this big, RAID 5 with spares is definitely a good idea -- RAID 5 gives you error checking, rather than just mindless mirroring. I would suggest at least 4 drives, maybe more. Each additional drive means less chance of a failed drive taking down the system. You can calculate the available space etc. here.

If you are keen on keeping downtime to an absolute, you might consider hot-pluggable SCSI or SAS drives.

[marietta]

I'm pretty sure that the "hugemem" SMP kernel will support upwards of 16Gb of RAM. For that many users, I would definitely suggest a lot more memory if there are going to be a lot of users accessing their email simultaneously.



With an install this big, RAID 5 with spares is definitely a good idea -- RAID 5 gives you error checking, rather than just mindless mirroring. I would suggest at least 4 drives, maybe more. Each additional drive means less chance of a failed drive taking down the system. You can calculate the available space etc. here.

If you are keen on keeping downtime to an absolute, you might consider hot-pluggable SCSI or SAS drives.

How much Ram would you go with?

RAID 5 Hardware or RAID 5 Software?

[David Harper]

2000 users screams "real server" to me - I would consider a proper HP or Dell machine with RHEL 4 support. And that would mean hardware RAID.

In terms of the RAM, with that many users it's pretty hard to estimate. Reading the system requirements, it is suggested that 512Mb RAM is sufficient for 25 users. That means that 12Gb or even 16Gb of RAM would be appropriate if you are going to have a heavy load on the server. If most of the 2000 mailboxes are just going to sit there and not do much then I guess 8Gb would probably suffice.

Perhaps someone who has experience with super-sized installs might comment.

[Stefano]

RAID 5 Hardware or RAID 5 Software?

in this case I'd go definitely with a SERIOUS hw raid controller.. and, of course, with a HP/DELL/IBM server with a good onsite support..

all IMO
Ciao
Stefano

[David Harper]

Off-topic: Stefano - 1 post shy of 2000 posts!!!! Congrats 

[marietta]

I'm looking at buying a Dell with a hardware RAID.
2 Quad Core processors
4-8GB of RAM maybe more
RAID 5 with 4 160GB Hard drives


The server I am running now:
SME 6.5
2 single processors
2 GB of RAM
2 36GB Drives Mirrored

I have been having most trouble deciding on amount of RAM.

Thanks for all the responses.

[David Harper]

If it were my server, I would definitely go with at least 8Gb of RAM. My suggestion is: If you deploy the server with 8Gb, you can always purchase more later on if you find that this is not enough.

I would also consider 5-6 hotpluggable SAS hard drives. For a server of this magnitude, SAS is definitely the right choice over SATA. And hotplug is worthwhile considering as well - it means that if a drive fails there is zero downtime.

[janet]

marietta

Run
top -i
or
htop
on your existing server to see how much memory is being used.

Most machines come with 4Gb standard these days and memory is not overly expensive, so lash out for at least 8Gb, and if that does not perform well enough then add more.