The Dell MD3460 controller array can support up to 120 drives with an MD3060e expansion tray attached. Single drive capacities have been steadily increasing, but transfer speeds have remained fairly constant. As a result, RAID6 rebuild times can exceed 24hrs when using 4TB drives. This is the main reason for choosing Dynamic Disk Pools over RAID6 - (DDP) provide lower rebuild times are possible since the RAID parity data is distributed compared to RAID6 because the hotspare space is spread across all drives in the pool. For the latest Fermi storage configuration, we are benchmarking eight 15-disk DDP volumes on each 120-drive MD3460+MD3060e storage config. Both arrays are dual-attached to a failover pair of servers (fermi-gpfs01,2). In a failover scenario, one machine could serve all sixteen DDP volumes.
The sgpdd-survey benchmark simulates performs parallel I/O using raw unformatted LUNs. The tests spawn and an increasing number of threads (thr) that write and read to an increasing number of concurrent regions (crg). As the tests progress, I/O becomes more random. This set of tests transfer data in The transfer operations use 1MB records/chunks (rsz). This is a local test that does not require any networking or formatted filesystem. The purpose is to understand the performance limits of the storage hardware before we create filesystems (GPFS, Lustre, etc.). The benchmark results show the MD3460 is capable of sustaining throughput well above 2GB/sec. In order to avoid networking bottlenecks, we may use 4x10Gb ethernet link aggregation instead of the usual 2x10Gb. We also have a limited number of 40Gb ports on the SLAC network.
One 15-disk LUN
Max write ~1GB/sec , Max read ~1GB/sec
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Mon Oct 6 12:07:30 PDT 2014 sgpdd-survey on /dev/raw/raw1 /dev/raw/raw2 /dev/raw/raw3 /dev/raw/raw4 /dev/raw/raw5 /dev/raw/raw6 /dev/raw/raw7 /dev/raw/raw8 from fermi-gpfs01
total_size 67108864K rsz 1024 crg 8 thr 8 write 4117.34 MB/s 8 x 515.06 = 4120.48 MB/s read 2449.74 MB/s 8 x 306.57 = 2452.55 MB/s
total_size 67108864K rsz 1024 crg 8 thr 16 write 4094.32 MB/s 8 x 512.19 = 4097.52 MB/s read 2568.02 MB/s 8 x 321.88 = 2575.07 MB/s
total_size 67108864K rsz 1024 crg 8 thr 32 write 4112.33 MB/s 8 x 514.45 = 4115.60 MB/s read 2524.38 MB/s 8 x 315.84 = 2526.70 MB/s
total_size 67108864K rsz 1024 crg 8 thr 64 write 4092.89 MB/s 8 x 512.29 = 4098.28 MB/s read 2590.98 MB/s 8 x 324.43 = 2595.44 MB/s
total_size 67108864K rsz 1024 crg 8 thr 128 write 4170.54 MB/s 8 x 521.89 = 4175.11 MB/s read 2190.28 MB/s 8 x 274.08 = 2192.61 MB/s
total_size 67108864K rsz 1024 crg 16 thr 16 write 4211.79 MB/s 16 x 263.89 = 4222.26 MB/s read 2805.23 MB/s 16 x 175.39 = 2806.24 MB/s
total_size 67108864K rsz 1024 crg 16 thr 32 write 4285.58 MB/s 16 x 268.08 = 4289.25 MB/s read 2899.50 MB/s 16 x 181.46 = 2903.29 MB/s
total_size 67108864K rsz 1024 crg 16 thr 64 write 4303.16 MB/s 16 x 269.66 = 4314.58 MB/s read 2822.25 MB/s 16 x 176.50 = 2823.94 MB/s
total_size 67108864K rsz 1024 crg 16 thr 128 write 4199.59 MB/s 16 x 263.23 = 4211.73 MB/s read 2749.91 MB/s 16 x 172.09 = 2753.45 MB/s
total_size 67108864K rsz 1024 crg 16 thr 256 write 4245.41 MB/s 16 x 266.08 = 4257.20 MB/s read 2714.66 MB/s 16 x 169.85 = 2717.59 MB/s
total_size 67108864K rsz 1024 crg 32 thr 32 write 4186.19 MB/s 32 x 130.94 = 4190.06 MB/s read 3971.82 MB/s 32 x 124.37 = 3979.80 MB/s
total_size 67108864K rsz 1024 crg 32 thr 64 write 4327.97 MB/s 32 x 135.37 = 4331.97 MB/s read 4067.70 MB/s 32 x 127.22 = 4071.04 MB/s
total_size 67108864K rsz 1024 crg 32 thr 128 write 4297.22 MB/s 32 x 134.41 = 4301.15 MB/s read 4096.38 MB/s 32 x 128.13 = 4100.04 MB/s
total_size 67108864K rsz 1024 crg 32 thr 256 write 4346.15 MB/s 32 x 136.18 = 4357.60 MB/s read 4124.96 MB/s 32 x 128.97 = 4127.20 MB/s
total_size 67108864K rsz 1024 crg 32 thr 512 write 4323.25 MB/s 32 x 135.60 = 4339.29 MB/s read 3862.30 MB/s 32 x 120.93 = 3869.63 MB/s
total_size 67108864K rsz 1024 crg 64 thr 64 write 4251.35 MB/s 64 x 66.79 = 4274.29 MB/s read 5469.94 MB/s 64 x 85.75 = 5488.28 MB/s
total_size 67108864K rsz 1024 crg 64 thr 128 write 4181.70 MB/s 64 x 65.56 = 4195.56 MB/s read 5487.44 MB/s 64 x 86.04 = 5506.59 MB/s
total_size 67108864K rsz 1024 crg 64 thr 256 write 4184.92 MB/s 64 x 65.63 = 4200.44 MB/s read 5498.97 MB/s 64 x 86.29 = 5522.46 MB/s
total_size 67108864K rsz 1024 crg 64 thr 512 write 4196.49 MB/s 64 x 65.93 = 4219.36 MB/s read 5412.16 MB/s 64 x 84.85 = 5430.30 MB/s
total_size 67108864K rsz 1024 crg 64 thr 1024 write 4203.88 MB/s 64 x 65.94 = 4219.97 MB/s read 5278.91 MB/s 64 x 82.67 = 5291.14 MB/s
total_size 67108864K rsz 1024 crg 128 thr 128 write 4168.32 MB/s 128 x 32.84 = 4202.88 MB/s read 4579.70 MB/s 128 x 35.92 = 4597.17 MB/s
total_size 67108864K rsz 1024 crg 128 thr 256 write 4080.65 MB/s 128 x 31.93 = 4086.91 MB/s read 4590.17 MB/s 128 x 36.00 = 4608.15 MB/s
total_size 67108864K rsz 1024 crg 128 thr 512 write 4090.79 MB/s 128 x 32.01 = 4096.68 MB/s read 4640.93 MB/s 128 x 36.39 = 4658.20 MB/s
total_size 67108864K rsz 1024 crg 128 thr 1024 write 4134.32 MB/s 128 x 32.35 = 4140.62 MB/s read 4540.94 MB/s 128 x 35.59 = 4555.66 MB/s
total_size 67108864K rsz 1024 crg 128 thr 2048 write 4153.93 MB/s 128 x 32.49 = 4158.94 MB/s read 4625.92 MB/s 128 x 36.29 = 4644.78 MB/s
total_size 67108864K rsz 1024 crg 256 thr 256 write 4251.26 MB/s 256 x 16.74 = 4284.67 MB/s read 4465.30 MB/s 256 x 17.53 = 4487.30 MB/s
total_size 67108864K rsz 1024 crg 256 thr 512 write 4236.42 MB/s 256 x 16.58 = 4245.61 MB/s read 4460.79 MB/s 256 x 17.50 = 4479.98 MB/s
total_size 67108864K rsz 1024 crg 256 thr 1024 write 4238.58 MB/s 256 x 16.69 = 4272.46 MB/s read 4538.00 MB/s 256 x 17.84 = 4567.87 MB/s
total_size 67108864K rsz 1024 crg 256 thr 2048 write 4189.18 MB/s 256 x 16.66 = 4265.14 MB/s read 4399.98 MB/s 256 x 17.24 = 4414.06 MB/s
total_size 67108864K rsz 1024 crg 512 thr 512 write 3876.79 MB/s 512 x 7.69 = 3935.55 MB/s read 5267.24 MB/s 512 x 10.41 = 5332.03 MB/s
total_size 67108864K rsz 1024 crg 512 thr 1024 write 4084.05 MB/s 512 x 7.99 = 4091.80 MB/s read 5179.54 MB/s 512 x 10.25 = 5249.02 MB/s
total_size 67108864K rsz 1024 crg 512 thr 2048 write 3980.91 MB/s 512 x 7.88 = 4033.20 MB/s read 4948.02 MB/s 512 x 9.91 = 5073.24 MB/s
total_size 67108864K rsz 1024 crg 1024 thr 1024 write 3080.92 MB/s 1024 x 3.01 = 3085.94 MB/s read 4366.60 MB/s 1024 x 4.39 = 4492.19 MB/s
total_size 67108864K rsz 1024 crg 1024 thr 2048 write 3152.38 MB/s 1024 x 3.19 = 3271.48 MB/s read 4446.49 MB/s 1024 x 4.41 = 4511.72 MB/s
total_size 67108864K rsz 1024 crg 2048 thr 2048 write 2296.72 MB/s 2048 x 1.14 = 2343.75 MB/s read 3883.91 MB/s 2048 x 1.98 = 4062.50 MB/s
Sixteen
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15-disk
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LUNs
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(host
...
failover
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scenario)
Max write ~4GB/sec , Max read ~10GB/sec
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