Intel
SSD DC S3500 Workload Characterization in RAID Configurations
December 2013 White Paper
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Figure 10. RAID 5 Maximum Latency for 3-drive and 8-drive
Configurations
Intel internal testing, October 2013
6.4 RAID 5 Performance Conclusions The RAID 5 write performance data illustrates the additional processing power required
of the RAID controller to calculate parity and stripe data across m ultiple drives. There is
diminished performance gain be adding drives when compared to RAID 1. Intel’s data
also shows that in mixed workloads and in pure reads, RAID 5 performs well, reaching
over 300K IOPS in 100% read at a queue of 8 per drive on eight drives. As the
workloads become more read heavy, latency drops from a high of 2.2 ms ( 100% write)
to a low of 140 µs (100% read). The highest throughput achieved was 2400 MB/s with
eight drives, 100% read, 128KB transfer size, and queue depth of 8. This leaves room
for possible improvement by adding more drives to the RAID set.
In configurations where RAID 5 would traditionally be used, SSDs would provide
significant performance gain over HDDs. Additionally, RAID 5 with SSDs could be used in
situations where RAID 5 with HDDs would not perform well.
The consistency of the drives is well demonstrated in these tests and shows that
Intel® SSD DC S3500 Series drives consistently offer higher performance with excellent
stability, even behind a RAID controller.