1 Rookie

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18 Posts

August 12th, 2009 23:00

Definition for IOPS :
I/Os per second; a measure of performance for a host-attached storage device or RAID controller.

Size of the unit depends what is configured. If an application tries 1000 times but storage is capable of only 500 requests in a second, it is 500 IOPS. (So element size/block size on OS plays major part to use more effectively)

For some example, refer the previous post on this forum : https://forums.emc.com/forums/thread.jspa?tstart=0&threadID=122253 - it got very good info including examples.

2 Intern

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392 Posts

August 13th, 2009 05:00

Throughput is the measurement of the number of individual I/O requests to the storage system or a device, such as a hard drive, can process over time. This measurement is independent of request size.

Throughput is measured in I/O operations per second (IOPS). Individual components, such as hard drives, up to entire storage systems can be rated for their throughput performance. Throughput is the measurement used to describe random or small-block I/O performance.

Throughput can be further divided into:

¿ Read IOPS: Read I/Os per second
¿ Write IOPS: Write I/Os per second
¿ Total IOPS: Average I/Os per second

This distinction is made because of the different amounts of storage system resources consumed in servicing a read operation versus a write. For a storage system I/O, it is very common to see the total IOPS stated with the ratio of read-to-write IOPS. An example is ¿10,000 IOPS, 70 percent reads.¿

Further information on I/O metrics can be found in the 'EMC CLARiiON Storage System Fundamentals for Performance and Availability' document found on PowerLink. If you cannot access the document, place your e-mail address in your forum profile and post here requesting it. I will send a copy of the document to you.
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