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IBM TotalStorage DS300 and DS400 Best Practices Guide
5.1 Performance considerations
SAN storage products such as the IBM TotalStorage DS300 and DS400
subsystems are designed to support server workloads. Since servers are
designed to handle multiple tasks in parallel, a DS300/DS400 is optimized to
perform well with multi-threaded workloads. Using a single-threaded utility such
as Copy or Xcopy does not take full advantage of the DS300/DS400 capabilities,
and does not show how a server that can support multi-threaded workloads will
really perform.
Similarly, dividing drives up into multiple smaller drive arrays, instead of using just
one large drive array, improves DS300/DS400 performance.
TotalStorage DS300 and DS400 performance improves when both controllers
are utilized. During performance evaluation, some evaluate the performance by
applying work to only one of the two controllers. In general, performance can be
improved by almost 2 times when work is applied to arrays on both controllers
instead of just one controller.
TotalStorage DS300 and DS400 performance can be improved by dividing the
drives into multiple smaller drive arrays, instead of using only one large drive
array. When using two controllers, performance can be improved by utilizing two
arrays per controller instead of one array per controller.
5.2 Configuration considerations
򐂰 An array can have up to 16 drives on a DS400 when RAID level 0,1 or 5 is
used. On a DS300, up to 14 drives are supported.
򐂰 A spanned array on a DS400 can have a total of 40 drives.
򐂰 Logical drive settings, such as RAID level and stripe size, are defined for an
array, and are the same for all logical drives in the same array.
򐂰 The maximum array size is 2TB.
򐂰 Up to 512 logical drives can be configured in a single array. Only 64 of those
logical drives can be configured by using the command line interface of the
TotalStorage DS300 or DS400.
򐂰 A network time protocol server (NTP) helps to have correct time on the
TotalStorage DS300 or DS400. All time stamps in the log files and messages
are correct and no manual intervention is required to keep them
synchronized. A time server can only be configured by using the command
line interface.
network ntp
172.16.0.9