HP StorageWorks Scalable File Share - Manual (Page 333)

SFS20 array configuration B–5
B.3 SFS20 array configuration
The graph in Figure B-1 shows the variation in the performance for write operations on an SFS20 array when
the array is configured with either one or two OST LUNs. In each case, the array is populated with twelve
250GB disks configured with ADG (RAID6) redundancy, and eight client nodes are writing to the LUNs over
a high-performance interconnect (that is, not a Gigabit Ethernet interconnect).
Figure B-1 Single SFS20 array write bandwidth
All results are based on tests using new, empty file systems with default MDS and OST mount options and
without quotas enabled.
The first bar on the graph shows the performance of a single 2TB LUN.
The second and third bars on the graph show the performance of two individual LUNs of 1TB each, when
they are individually accessed by eight client nodes, with each client node writing a separate 4GB file with
a file stripe count of one.
The results show that when there is no concurrent activity, the performance of each of the 1TB LUNs is
approximately equivalent to the performance of a single 2TB LUN.
However, the remaining three bars on the graph show the effect of concurrent access to each of the 1TB
LUNs through three different striping arrangements, as follows:
• Each client node stripes files across both LUNs (that is, a file stripe count of two) with the same start
LUN
• 50% of the client nodes stripe files across each LUN
• Random striping with eight client nodes, using a file stripe count of 2
In each of these cases, the aggregate bandwidth available from the array is significantly reduced.
For maximum performance, HP recommends configuring SFS20 arrays (where 160GB or 250GB disks are
used) with one large 2TB LUN per array.
Single SFS20 Write Bandwidth
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