3. Hardware considerations

Sizing and implementing Kopano Archiver requires careful planning to ensure that the product can perform to expectations and scaling as the customer requirements grow and fits in the existing infrastructure.

3.1. CPU

In most deployment scenarios the Kopano Archiver will be installed on a dedicated server which doesn’t provide any other services. The most heavy actions performed on the archive server is the actual archive run, which is typically done once or twice a day. This archive run will in general do a lot of database transactions and is not running CPU intensive calculations.

The archiver run will archive the mailboxes one by one. For the right choice of the amount of CPU’s it’s recommended to use a multi-core system where one core is reserved for the Kopano-server, one for the MySQL database server and one for the actual Archive controller.

The advised amount of CPU cores is 4 where the prefered archicture is 64bits, so more than 4Gb of memory can be allocated by processes.

3.2. Memory

In normal setups of Kopano Core, memory is one of the most important hardware components as both MySQL and Kopano-server cache requested data, so the second time the calendar or inbox is opened all items will be retrieved from the cache. In an archiving setup with the stubbing feature enabled, the archived data is only accessed when an archived email is really opened. In this case the advantage of caching is limited, as the archived emails are normally not accessed over and over again. However when the users open the archive store as a secondary mailbox, caching is more important as the user will directly access the archive store.

The advised amount of memory is:

Amount of archive users Stubbing enabled No stubbing
<500 2GB 4GB
500 - 2000 4GB 8GB
>2000 8GB 16GB

3.3. Storage

In most cases, you require RAID-based storage to achieve your storage requirements. To maintain performance and reliability, consider hardware-based RAID rather than software-based RAID. To achieve redundancy on striped arrays while maintaining performance, consider the RAID scheme carefully.

RAID level 5 is popular to arrange cost-effective methods of achieving redundancy while keeping a good read performance. However, write actions on RAID level 5 will cost performance for storing parity bits. Therefore, in most cases discussed, a RAID1 or RAID10 should be considered. The RAID controller should also provide a battery-backed read and write cache to aid performance and prevent data corruption at power failures.

Before you use partitions on a storage area network (SAN), consider the I/O load together with any other applications that are already using the SAN to ensure that the performance can be maintained.

Ideally, discuss the implementation with the storage vendor or responsible to ensure that you achieve the best performance. Typically, you should create LUNs across as many suitable disks as possible, using entire disks rather than partial disks to prevent multiple I/O-intensive applications from using the same disks.

3.4. Virtual vs Physical

When above storage and memory requirements are matched, the Kopano Archiver can run on both virtual as physical servers. Most organisation use the Kopano Archiver on a virtual platform, as this is the default in todays data center environments.