디스크타입별 IOPS

출처 : 위키피디아 (http://en.wikipedia.org/wiki/IOPS#Examples)

노트북 SSD 테스트결과 4Kb 기준 Read/Write Test에서 475IOPS가 나오네요... 음...

All 로 하면 700 이 넘는 결과가 나오는데 이유가 뭔지 

IOPS (Input/Output Operations Per Second) is a common benchmark for hard disks, solid state drives, and other computer storage devices. As with any benchmark, IOPS numbers published by drive and SAN vendors can be manipulated and do not guarantee real-world application performance.^[1]

IOPS can be measured with applications such as Iometer (originally developed by Intel) as well as IOzone and FIO^[2] and is primarily used with servers to find the best storage configuration.

The specific number of IOPS possible in any system configuration will vary greatly depending upon the variables the tester enters into the program, including the balance of read and write operations, the mix of random or sequential access patterns, the number of worker threads and queue depth, as well as the data block sizes.^[1] There are other factors related to the system setup, drivers, OS background operations, etc. which can also affect the IOPS results. Also, when testing solid-state drives, there are preconditioning considerations that must be taken into account.^[3]

Contents  [hide] 1 Performance characteristics 2 Examples 3 See also 4 References

[edit]Performance characteristics

The most common performance characteristics that are measured or defined are as follows:

Measurement	Description
Total IOPS	Total number of I/O operations per second (when performing a mix of read and write tests)
Random Read IOPS	Average number of random read I/O operations per second
Random Write IOPS	Average number of random write I/O operations per second
Sequential Read IOPS	Average number of sequential read I/O operations per second
Sequential Write IOPS	Average number of sequential write I/O operations per second

For hard disk drives and similar electromechanical storage devices, the random IOPS numbers are primarily dependent upon the storage device's random seek time, whereas the sequential IOPS numbers (especially when using a large block size) typically indicate the maximum sustained bandwidth that a storage device can handle. Often sequential IOPS are reported as a simple MB/s number. Where as:

IOPS * TransferSizeInBytes = BytesPerSec (with the answer typically converted to MegabytesPerSec)

Some hard drives will improve in performance as the number of outstanding IO's (i.e. queue depth) increases. This is usually the result of more advanced controller logic on the drive performing command queuing and reordering commonly called either Tagged Command Queuing (TCQ) or Native Command Queuing (NCQ). Most commodity SATA drives either cannot do this, or their implementation is so poor that no performance benefit can be seen.^{[citation needed]} Enterprise class SATA drives, such as the Western Digital Raptor and Seagate Barracuda NL will improve by nearly 100% with deep queues [1]. High end SCSI drives more commonly found in servers generally show much greater improvement, with the SeagateSavvio exceeding 400 IOPS—more than doubling its performance.^{[citation needed]}

While traditional harddisks have about the same IOPS for read and write, USB Flash drives and most Flash-based solid-state drives are much slower writing than reading due to the fact that FLASH memory must delete the memory block before writing to it.This has caused hardware test sites to start to do IOPS testing, which makes numbers available that have been independently measured.

Newer flash SSD drives such as the Intel X25-E have much higher IOPS than traditional hard disk drives. In a test done by Xssist, using IOmeter, 4KB RANDOM 70/30 RW, queue depth 4, the IOPS delivered by the Intel X25-E 64GB G1 started around 10000 IOPs, and dropped sharply after 8 minutes to 4000 IOPS, and continued to decrease gradually for the next 42 minutes. IOPS vary between 3000 to 4000 from around the 50th minutes onwards for the rest of the 8+ hours test run. ^[4] Even with the drop in random IOPS after the 50th minute, the X25-E still has much higher IOPS compared to traditional hard disk drives.

[edit]Examples

Some ballpark numbers (see e.g. Toms Hardware on Intel X25-M[2] and X25-E[3], and on Fusion-io's ioDrive[4].

Device	IOPS	Notes
7200 RPM SATA drives	~90 IOPS[citation needed]
10k RPM SATA drives, queue depth 1	~130 IOPS	fio -readonly -name iops -rw=randread -bs=512 -runtime=20 -iodepth 1 -filename /dev/sda -ioengine libaio -direct=1
10k RPM Serial Attached SCSIdrives	~140 IOPS[citation needed]
15k RPM Serial Attached SCSIdrives	~180 IOPS[citation needed]
10k RPM SATA drives, queue depth 24	~290 IOPS	fio -readonly -name iops -rw=randread -bs=512 -runtime=20 -iodepth 24 -filename /dev/sda -ioengine libaio -direct=1
Simple SLC SSD	~400 IOPS[citation needed]
Intel X25-M (MLC; As of March 2010)	~8,600 IOPS	Intel's data sheet claims 8,600 IOPS and 35,000 IOPS for writes and reads, respectively.
Intel X25-E (SLC; As of March 2009)	~5,000 IOPS	Intel's data sheet claims 3,300 IOPS and 35,000 IOPS for writes and reads, respectively. 5,000 IOPS are measured for a mix. Intel X25-E G1 has around 3 times higher IOPS compared to the Intel X25-M G2 [5].
OCZ Z-Drive e84, a PCI Express SLC Solid State Drive	16,000 IOPS	Maximum read/write speed of 800/750 MB/s)[citation needed].
G.Skill Phoenix Pro et. al.	~20,000 IOPS	SandForce-1200 based SSD drives with enhanced firmware, states up to 50,000 IOPS, but real-world performance shows for all drives from different manufacturers ~25,000 IOPS for random read and ~15,000 IOPS for random write. [6]
ioDrive, a PCI-Express card with Flash	>80,000 IOPS[citation needed]
DDRdrive X1, a May 2009 PCI Express based solid-state drive	300,000+ (512B Random Read IOPS) and 200,000+ (512B Random Write IOPS) [7][8][9][10]
RamSan-630	500,000 random read IOPS[11]
Violin Memory Appliance	1,000,000+ Random Read IOPS[12]

[edit]See also

• Instructions per second
• Performance per watt

[edit]References

1. ^ ^a b Lowe, Scott (March 11th, 2010). "Calculate IOPS in a storage array". ZDNET. Retrieved 2010-06-04.
2. ^ Axboe, Jens. "Flexible IO Tester". Retrieved 2010-06-04.(source available at http://git.kernel.dk/)
3. ^ Smith, Kent (Aug 11th, 2009). "Benchmarking SSDs: The Devil is in the Preconditioning Details". SandForce. Retrieved 2010-06-04.
4. ^ "Intel X25-E 64GB G1, 4KB Random IOPS, iometer benchmark". March 27th, 2010. Retrieved 2010-04-01.
5. ^ "Intel X25-E G1 vs Intel X25-M G2 Random 4KB IOPS, iometer". May, 2010. Retrieved 2010-05-19.
6. ^ http://www.tweakpc.de/hardware/tests/ssd/gskill_phoenix_pro/s05.php
7. ^ http://www.ddrdrive.com/ddrdrive_press.pdf
8. ^ http://www.ddrdrive.com/ddrdrive_brief.pdf
9. ^ http://www.ddrdrive.com/ddrdrive_bench.pdf
10. ^ http://www.pcper.com/article.php?aid=704
11. ^ http://www.ramsan.com/products/ramsan-630.asp
12. ^ http://violin-memory.com/Performance