SandForce 1222 SSD Testing, Part 1: Initial Throughput Results

SandForce is quickly becoming one of the dominant companies in the SSD controller world. They comes in a range of SSDs from consumer SSDs such as the one discussed in this article to enterprise level SSDs. The really cool thing in their controllers is that they use real-time data compression to improve both performance and increase the longevity of the SSD. They key to this working is the compressibility of your data. If your data is compressible then you can get a performance boost as well as a longevity boost. But the question is how much performance is affected but the compressibility of the data.

In this article, I took a consumer SSD that uses a SandForce 1222 based SSD and ran some throughput tests against it using IOzone and data with different compressibility levels. I’ve used IOzone before for throughput testing but for this particular testing, I used the ability of IOzone to vary the level of dedupability or compressibility of the data.

I ran 13 different I/O tests using IOzone: write, re-write, random write, record rewrite, fwrite, frewrite, read, reread, random read, backwards read, stride read, fread, and freread. Each test was run 10 times with four different record sizes, (1) 1MB, (2) 4MB, (3) 8MB, and (4) 16MB. Also, three different data compression levels were tested: 98% compressible, 50% compressible, and 2% compressible. The average and standard deviation of each test is reported graphically.

All of the write tests with the exception of the record rewrite exhibited the same general behavior. More specifically:

• As the level of compressibility decreases, the performance drops off fairly quickly
  
• As the level of compressibility decreases, there is little variation in performance as the record size changes (over the record sizes tested).
  

The absolute values of the performance varied for each test, but for the general write test, the performance went from about 260 MB/s (close to the rated performance) at 98% data compression to about 97 MB/s at 2% data compression for a record size of 1 MB.

In the case of record rewrite,the average performance actually improved as the compressibility decreased but the standard deviations for a record size of 1MB were quite large. In addition, the throughput was smaller than for the write or re-write tests. And finally, the performance drops off fairly significantly when going from a record size of 1MB to 4MB.

All of the read tests exhibited the same general behavior. Specifically,

• The performance drops only slightly with decreasing compressibility (dedupability)
  
• As the level of compressibility decreases, the performance for larger record sizes actually increases
  
• As the level of compressibility decreases, there is little performance variation between record sizes
  

Again, the absolute performance varies for each test, but the trends are the same. But basically, the real-time data compression does not affect the read performance as much as it does the write performance.

The key observation you should take from these results is that the performance varies with the level of data compression. If the data is compressible then you will get pretty amazing performance from an inexpensive SSD and if you data is compressible as granite, then you may not get the best performance from a SandForce controlled SSD. The key question for you is how compressible is your data? That question can be difficult to answer but I think you would be surprised by how compressible data can be. Remember that you aren’t concerned with the overall compressibility of a file, but rather how compressible a chunk of the data can be.

SandForce has added another “knob” to the ability of tuning storage solutions – real-time data compression in the storage device (SSD). While we can’t really control turn this knob to improve performance of change the behavior of the overall storage solution, it can be used in an overall design to improve performance and longevity of SSD storage solutions. I think of this as an opportunity. We can study our data to look for opportunities that it can be compressed efficiently or we can change our applications to take advantage of SandForce controllers.

In the next article I’ll present some IOPS testing of the same SSD. Stay tuned.

Table of Results

The first two tables of results are for the 1MB record size. Table 1 below presents the throughput in KB/s for the file systems for the 6 write tests for all three data compression levels.

Table 1 – IOzone Write Performance Results with a Record Length of 1MB, a File Size of 16GB, for all three data compression levels

Compression Level	Write KB/s	Re-write (KB/s)	Random write (KB/s)	Record re-write (KB/s)	fwrite (KB/s)	frewrite (KB/s)
98%	259,867.10 2,288.98	262,817.50 1,837.59	240.748.80 6,154.25	948,460.10 11,794.89	260,159.60 3,750.41	262,224.60 1,912.10
50%	128,515.40 565.47	127,350.30 439.92	122,132.30 602.71	1,239,838.00 175,767.76	127,065.50 594.64	127,008.10 320.65
2%	97,113.50 753.56	95,722.80 596.64	92,497.20 419.70	114,5650.00 167,156.10	97,433.20 496.51	95,591.70 640.73

Table 2 below presents the read throughput in KB/s for the configurations for the 7 read tests for a record length of 1MB for all three data compression levels.

Table 2 – IOzone read Performance Results with a Record Length of 1MB, a File Size of 16GB, for all three data compression levels

Compression Level	Read (KB/s)	Re-read (KB/s)	Random read (KB/s)	Backwards read (KB/s)	Strided read (KB/s)	fread (KB/s)	freread (KB/s)
98%	225,287.40 295.71	225,667.40 246.14	223,668.40 229.79	232,015.00 6,527.68	264,430.40 6,234.18	228,108.20 331.11	228,383.50 400.09
50%	201,998.30 447.60	206,083.00 2,686.91	210,945.20 410.51	228,791.10 8,177.77	248,220.90 1,031.81	203,992.90 414.03	210,024.70 2,425.19
2%	191,991.90 362.27	194,613.60 1,517.10	202,468.70 331.52	218,469.80 9,711.30	236,463.90 6,828.49	193,270.60 69.28	197,003.20 2,113.24

Table 3 below presents the throughput in KB/s for the file systems for the 6 write tests for all three levels of data compression for the case of a 4MB record ize.

Table 3 – IOzone Write Performance Results with a Record Length of 4MB, a File Size of 16GB, for all three data compression levels

Compression Level	Write KB/s	Re-write (KB/s)	Random write (KB/s)	Record re-write (KB/s)	fwrite (KB/s)	frewrite (KB/s)
98%	259,636.00 2,876.35	264,365.50 284.30	261,707.50 2,231.57	489,360.30 8,543.12	260,444.30 1,031.41	263,937.70 268.36
50%	128,393.70 632.91	126,700.10 391.06	123,144.50 340.23	712,719.60 38,566.16	127,828.80 286.79	126,818.40 312.61
2%	97,854.40 546.40	96,097.30 562.56	94,784.10 423.01	749,340.20 49,796.75	96,312.00 3096.89	95,834.60 679.52

Table 4 below presents the read throughput in KB/s for the configurations for the 7 read tests for a record length of 4MB for all three levels of data compression.

Table 4 – IOzone read Performance Results with a Record Length of 4MB, a File Size of 16GB, for all three levels of data compression

Compresion Level	Read (KB/s)	Re-read (KB/s)	Random read (KB/s)	Backwards read (KB/s)	Strided read (KB/s)	fread (KB/s)	freread (KB/s)
98%	185,799.20 446.84	186,003.20 380.94	196,870.50 452.72	212,707.60 580.82	220,705.40 367.90	187,464.20 466.91	187,539.90 422.39
50%	200,175.80 484.83	206,240.60 2,083.58	216,113.40 415.51	237,721.20 376.93	250,362.10 393.04	200,846.10 403.95	206,420.10 1,688.87
2%	191,830.20 1,853.31	194,658.60 1,879.87	210,661.20 322.21	234,742.40 370.98	240,858.80 4,520.73	192,249.70 180.95	196,327.50 2,310.93

Table 5 below presents the throughput in KB/s for the file systems for the 6 write tests for all three levels of data compression.

Table 5 – IOzone Write Performance Results with a Record Length of 8MB, a File Size of 16GB, for all three levels of data compression

Compression Level	Write KB/s	Re-write (KB/s)	Random write (KB/s)	Record re-write (KB/s)	fwrite (KB/s)	frewrite (KB/s)
98%	201,435.20 12,910.26	197,160.70 4,216.48	196,540.40 3,818.25	409,745.50 4,134.56	183,740.30 2,396.45	174,528.60 3,947.52
50%	127,852.10 1,010.09	124,798.20 309.14	124,091.80 301.98	628,919.00 10,397.27	127,133.10 229.97	125,422.00 285.08
2%	98,201.40 388.01	96,797.60 277.94	95,664.20 526.36	643,606.90 14,595.09	97,800.80 628.66	95,982.70 715.15

Table 6 below presents the read throughput in KB/s for the configurations for the 7 read tests for a record length of 8MB for all three levels of data compression.

Table 6 – IOzone read Performance Results with a Record Length of 8MB, a File Size of 16GB, for all all three levels of data compression

Compression Level	Read (KB/s)	Re-read (KB/s)	Random read (KB/s)	Backwards read (KB/s)	Strided read (KB/s)	fread (KB/s)	freread (KB/s)
98%	160,866.10 548.27	161,000.70 440.51	170,620.80 3,620.09	184,403.80 3,036.95	188,468.50 435.83	161,329.20 398.43	161,882.50 843.89
50%	192,996.90 412.83	196,348.20 1,631.00	213,035.20 414.83	231,573.20 732.80	239,764.00 343.25	193,825.90 221.58	196,757.30 1,563.09
2%	191,435.30 531.57	196,460.60 3,050.22	213,130.30 734.09	234,906.50 1,173.67	242,374.50 3,024.55	192,102.20 318.33 /font>	195,679.20 1,954.18

Table 7 below presents the throughput in KB/s for the file systems for the 6 write tests for all three levels of data compression.

Table 7 – IOzone Write Performance Results with a Record Length of 16MB, a File Size of 16GB, for all three data compressions

Compression Level	Write KB/s	Re-write (KB/s)	Random write (KB/s)	Record re-write (KB/s)	fwrite (KB/s)	frewrite (KB/s)
98%	187,376.40 7,335.08	194,595.00 8,631.12	194,275.40 8,376.24	407,065.80 2,294.84	194,750.80 8,682.39	197,457.20 942.71
50%	124,560.80 975.37	122,228.00 900.37	122,249.00 528.17	633,716.50 10,578.84	124,419.70 1,007.73	122,483.20 1,215.24
2%	98,061.10 599.59	96,510.70 529.34	95,636.40 307.13	647,510.20 6,295.92	97,745.10 789.20	95,864.40 852.17

Table 8 below presents the read throughput in KB/s for the configurations for the 7 read tests for a record length of 16MB for all three levels of data compression.

Table 8 – IOzone read Performance Results with a Record Length of 16MB, a File Size of 16GB, for all three levels of data compression

Compression Level	Read (KB/s)	Re-read (KB/s)	Random read (KB/s)	Backwards read (KB/s)	Strided read (KB/s)	fread (KB/s)	freread (KB/s)
98%	159,715.40 426.48	160,472.20 1,121.55	173,767.70 1,067.26	183,805.10 1,015.83	187,475.80 1,190.98	160,328.00 421.81	161,214.00 667.26
50%	191,687.90 668.67	193,903.30 1,657.78	215,117.90 1,050.15	231,211.20 670.64	239,107.40 1,195.25	192,657.80 459.52	195,210.80 1744.49
2%	191,272.80 324.34	195,085.40 1,876.13	216,352.30 938.97	234,983.00 1,228.71	241,631.10 958.78	192,134.80 223.96	195,617.60 1,600.22