Dell POWERVAULT MD1000 User Manual

Page 27

A REFERENCE GUIDE FOR OPTIMIZING DELL™ MD1000 SAS SOLUTIONS

VER A00

PAGE 27

5/06/2005

RAID 10

RAID 10 has good I/O performance, excellent availability and redundancy. The biggest drawback
of RAID 10 is that it requires twice the number of physical disks needed for data. This RAID
configuration should be used in situations requiring maximum availability, redundancy, and
performance.

RAID 5

RAID 5 has good I/O performance, data protection and requires only one additional physical disk
than the number needed for data. RAID 5 should be used in situations where maximum storage
capacity is required along with a moderate amount of data protection.

RAID 50

A balance between RAID 5 and RAID 10, this solution offers good I/O performance, availability and
good storage capacity. This configuration offers slightly higher performance than RAID 5, but
requires multiple additional physical disks than the number needed for data. It does however
provide greater storage capacity than a RAID 10 solution with a decrease in performance and data
protection. This should be used in situations where greater redundancy and data protection is
required as well as a reasonable storage capacity.

Concatenated

This solution is not recommended due to lack of data protection and redundancy and no
performance gain.

Note: For more details on RAID configurations see the Dell ‘Getting Started with RAID’ document
(http://support.dell.com/support/edocs/storage/RAID/RAIDbk0.pdf)

Application specific guidelines

E-Mail Servers

The storage requirements for e-mail servers can vary depending on the size, the amount, and the
type of users. While small departmental e-mail servers may work well with a small amount of
storage and limited features; large corporate e-mail servers normally require greater storage
capacity, very high availability, performance, and scalability. I/O profiles will vary depending on the
number of users and type of mail and attachments sent.

Table 6: Email Server General I/O profile

I/O Profile
(Read/Write)

I/O Profile
(Sequential/Random)

Bandwidth

I/O
Size

Latency
Sensitivity

Growth
Rate

Criticality

60/40

Random

Heavy

High