Installation manual

paper published by Microsoft for the correct configuration. You can also use EMC Dell/EMC CX
Series Storage Solutions Microsoft Exchange 2003 Best Practices on EMC Powerlink.
Backup-to-disk
Backup-to-disk is sequential in nature and typically uses medium (64 KB) to large (256 KB) I/O
sizes. For these types of applications use ATA or SATA-II drives, although you can use Fibre
Channel drives. To calculate the number of Fibre Channel drives use the “rule-of-thumb” values
in EMC Dell/EMC CX Series Best Practices for Fibre Channel Storage.
For ATA or SATA-II drives use RAID 3 4+1 or 8+1.
WEB intelligence report repositories
WEB intelligence report repositories are typically data-warehouse-like environments. They collect
data for later analysis. The data collection may be either transactional or periodic collection
sessions. The analysis is likely to be scans and builds. The I/O profile for these environments is
highly sequential reads and writes. During queries, the writes go to a temp area. During data
collection, writes go to the main repository.
Use 8+1 RAID 5 LUNs. Fibre Channel drives should be used for high performance, especially if
the data-collection method is transactional. If the data-collection method is sequential, then ATA
or SATA-II drives should suffice.
Drive count
For RAID 5 the best all-around configuration is five or nine disks. RAID 5 groups can be
configured with three to 16 disks.
For RAID 1/0 EMC recommends four to ten disks. RAID 1/0 groups must be grown by adding two
disks at a time.
Drive types
For Fibre Channel use 10k rpm drives for back-end loops running at 2 Gb/s or 15k rpm drives for
back-end loops running at 4 Gb/s.
Fibre Channel applications include: OLTP, file and print, data warehousing and video.
ATA or SATA-II applications include: backup-to-disk, data warehousing and online archive.
Hot spares
A hot spare is an extra drive for each drive type. EMC strongly recommends a minimum of one
hot spare for each type (ATA, SATA-II or FC) of disk in the storage system and one more for
every 30 drives of the same type. For hot spares to be effective they must be as large as the
largest drive of that type in the storage system. Remember, however, if you have high-speed
drives in your configuration, you may also want hot spares that match the speed of the fastest
drive. For example, if the system has 146 GB and 300 GB FC drives in the system, the hot
spares must be 300 GB to be able to service the 300 GB drives.
Consult the Dell/EMC CX Series Global Hot Spares – Characteristics and Usage Strategies white
paper for additional details on hot spares.
Drive type
Dell/EMC CX Series supports two different drive types. Within drive types there are different
capacities and rotational speeds. This section addresses how these apply to hot spares.
Dell/EMC CX Series Initial Configuration
Best Practices Planning 13