I am planning to deploy a ZCS machine in a remote DC on colocation. Using the latest Community edition Hardware:
- 2x SAS disks for OS in raid1,
- 8x SAS disks in raid10 for Zimbra,
- 32Gb RAM 8 CPU cores
Requirements:
- Normal system functionality
- Everyting must be encrypted (currently considering the standard LUKS)
- Backup to another machine in the same DC, not using 3rd party software
- The possibility of a fast restore to another machine in case of failure. Replication to a standby machine would be even better
Questions:
- Any comments on the hardware?
- How much of a performance hit would the encryption mean?
- Which of the existing backup scripts is preferable? I need the possibility to restore up to 1-2 months back, weekly full, and daily incrementals would be grand. Brick level - extra plus
- What other DR options are available? What about HA?
- How is the installation done in this case? Simply use /opt as the mountpoint for the raid10, or..?
- Which of the supported OS is the most stable and easy to maintain with a large number of mailboxes? I am kind of disappointed in CentOS, anyone aware of how SL performs?
Any additional comments or anything I might have missed also welcome
You don't mention the number of users you plan to manage under this setup. I can comment on my experience with Zimbra installations of up to 150 users, though...
The hardware is fine, if not overkill on the RAM. Zimbra will hammer your CPUs by default. There are some tuning options that will help.
On the OS/disk side, I think it depends on the specific hardware. If it were HP/Dell (SmartArray or PERC), I'd create a 10-disk RAID 1+0 volume and carve logical drives out of it; maybe even keep a hot-spare or two if the server is in a co-location facility. If not, you can simply mount the 8 SAS disks as /opt. Make sure your storage controller has a write cache and a battery/flash-backup unit.
As for OS, what's your problem with CentOS at this point? I would probably head that direction over Scientific Linux. If you elect to use CentOS, enable the continuous-release repository (cr) to keep it roughly at the Red Hat EL6.1 level. I don't see an appreciable difference in performance between SL and CentOS, though.