This technical white paper discusses Dell EMC’s solution for 100,000 Exchange mailboxes with 70 GB size per mailbox, supporting up to 150 messages per day in a four-copy DAG. The solution uses the Dell EMC DSS 7000/7500 chassis/sleds for the Exchange mailbox server role and uses the internal storage of DSS7000 for storing the Exchange mailbox databases and transaction logs.

DSS 7000/DSS 7500 is a 4U 90x drives ultra-dense storage server. These systems consist of DSS 7000, which is the Chassis and 2x DSS 7500 sleds with a highly expandable memory and impressive I/O capabilities. This standard width, 4U system offers the lowest cost per GB in the industry today.

DSS 7000/DSS 7500 can readily handle data-intensive applications that require a large storage capacity such as email and archive solutions. It delivers the performance and availability required for mission-critical email and is a great hardware building block for super-large organizations with huge mailboxes.

The Dell EMC DSS 7000/DSS 7500 has the following key areas of differentiation:

  • Ultra density: Up to 90x 3.5” HDDs and two independent 2S sleds in a 4U form factor
    • A selection of high performance E5-2600 v4 series processors
    • Flexible backplane enables customizable HDD combinations
  • Systems management with support for IPMI 2.0, BMC, remote KVM, and LDAP
  • Redundant hot-plug 1100 W AC power supply for added reliability
  • Serviceable nodes: ability to service one node while the other is running. Both nodes are working independently and control a maximum of 45 HDDs each. Shutting down one node for service does not impact the other node.
  • Each sled has two boot drives and 4 PCIe Gen 3 slots
  • Up to 384 GB of memory with 12 DDR4 DIMM slots per server node

In this solution, Dell EMC DSS 7000/DSS 7500 with 3.5-inch LFF drives are used as Mailbox Servers. The DSS 7000 / DSS 7500 combination provides SAS-based internal storage with RAID. The solution uses 90x 3.5-inch LFF 7.2KRPM NL-SAS disks across one DSS 7000 chassis with two DSS 7500 sleds in the chassis. The solution also uses four back-accessible 1.8-inch SSDs—two each across DSS 7500 sleds. The disk layout is listed below:

  • Two rear-accessible SSDs (in RAID 1 container) for the operating system, applicationfiles and Exchange Transport database per DSS 7500 sled
  • 42 disk drives (in RAID 0 containers) for the Exchange database and its transactionlogs
  • One disk drive for Restore LUN
  • One disk drive for Auto-reseed volume
  • One disk drive as a spare drive

The solution has a 4-copy DAG Layout (Active/Active) with Exchange Servers distributed between two sites: Site A and Site B. Each server node has 42-RAID 0 LUNs hosting one active and three passive databases per LUN during normal operating conditions. Each of these databases hosts 23 users with 70 GB mailbox size. Thus, a single server can accommodate 475 mailboxes in normal runtime. Sixteen such servers in one DAG (8 each in Site A and Site B) provide Exchange Mailbox Services for 7,600 users. The solution can be scaled out for 100,000 users as outlined in this white paper by implementing additional DAGs.