Mailbox Nodes and SAN
Zimbra mailboxes are stored on Mailbox Servers which boot directly from a highly redundant Storage Area Network (SAN). This means that recovery from physical server failure can be accomplished very quickly as Mailbox Servers can simply be restarted on a spare physical host. All mailbox data is also stored on on the SAN for maximum reliability.
SAN snapshots are taken regularly throughout the day, nightly backups are made of all mailboxes to a separate backup system and these backups are transferred off site to two separate data centres where they are stored for 30 days.
Multiple Data Suites
As well as servers with redundant power supplies and network connections, racks with redundant A/B power feeds and a true Tier III, enterprise class data centre, In-Tuition are careful to distribute key equipment across two independently powered suites with the Data center for additional resilience.
Storage Area Network (SAN)
In-Tuition’s SAN is based on Lefthand Networks SAN/iQ® storage software. The patented architecture distributes intelligence across storage nodes, then stripes data over the entire cluster, eliminating any single point of failure.
In-Tuition’s SAN/iQ® implementation consists of multiple storage nodes, each with 15,000 RPM, SAS drives, configured with RAID 10. Whilst RAID 10 offers the best combination of redundancy and performance, a lot of space is wasted because data is striped and mirrored across all available drives. For additional redundancy, In-Tuition configure the Lefthand software to mirror all mailbox data across at least two nodes which doubles the required storage space. In practise, therefore, for each 1GB of mailbox data, In-Tuition actually require 4GB of raw SAN storage space (not including snapshot storage space requirements which vary according to usage) plus approximately 8GB of backup storage space.
Clearly, In-Tuition could increase capacity, and therefore lower costs by a factor of 4, by reducing the amount of redundancy employed. However, given the critical nature of email data, In-Tuition’s policy is for maximum realistic possible data protection.
