EMC RAID System Test

The storage processor enables the administrator in serving the purpose of the following:

creating raid groups
binding LUNs
execute CLI commands
perform read/write operations from external server to SAN

Excessive usage of or heavy I/O load on a single storage processor can cause a marked deterioration in the overall performance of the storage sub-system, as it is indicative of severe deficiencies in the load-balancing algorithm that drives the storage processors. Using the EMC RAID System test, administrators can easily monitor the current state, usage, and load on each of the storage processors on the storage system, quickly detect an overload condition, precisely point to the storage processor that is bearing its brunt, and promptly initiate measures to resolve the issue, so as to ensure the optimal performance of the storage system.

This test is disabled by default. To enable the test, go to the enable / disable tests page using the menu sequence : Agents -> Tests -> Enable/Disable, pick the EMC Clariion SAN as the desired Component type, set Performance as the Test type, choose the test from the disabled tests list, and click on the < button to move the test to the ENABLED TESTS list. Finally, click the Update button.

Target of the test : An EMC CLARiiON storage device

Agent deploying the test : A remote agent

Outputs of the test : One set of results for each storage processor on the storage system.

Configurable parameters for the test
Parameter	Description
Test Period	How often should the test be executed.
Host	The IP address of the storage device for which this test is to be configured.
Port	The port number at which the storage device listens. The default is NULL.
User Name and Password	The SMI-S Provider is paired with the EMC CIM Object Manager Server to provide an SMI-compliant interface for CLARiiON arrays. Against the User and Password parameters, specify the credentials of a user who has been assigned Monitor access to the EMC CIM Object Manager Server paired with EMC CLARiiON’s SMI-S provider.
Confirm Password	Confirm the Password by retyping it here.
SSL	Set this flag to Yes, if the storage device being monitored is SSL-enabled.
IsEmbedded	By default, this flag is set to False for an EMC CLARiiON device. Do not disturb this default setting.
SerialNumber	If the SMI-S provider has been implemented as a proxy, then such a provider can be configured to manage multiple storage devices. This is why, you will have to explicitly specify which storage system you want the eG agent to monitor. Since each storage system is uniquely identified by a Serial number, specify the same here. The serial number for an EMC CLARiiON device will be of the format, FCNMM094900059.
NameSpace	Specify the NameSpace that uniquely identifies the profiles specific to the provider in use. For EMC CLARiiON, this parameter will be set to root/emc by default.

Measurements made by the test

Measurement

Description

Measurement Unit

Interpretation

Operational status

Indicates the current operational state of this storage processor.

The values that this measure can report and their corresponding numeric values are discussed in the table below:

Measure Value	Numeric Value
OK	0
In Service	1
Power Mode	2
Completed	3
Starting	4
Dormant	5
Other	6
Unknown	7
Stopping	8
Stressed	9
Stopped	10
Supporting Entity in Error	11
Degraded or Predicted Failure	12
Predictive Failure	13
Lost Communication	14
No Contact	15
Aborted	16
Error	17
Non-Recoverable Error	18

Note:

By default, this measure reports the Measure Values discussed above to indicate the operational state of a storage processor. In the graph of this measure however, operational states are represented using the numeric equivalents only.

Detailed operational status

Describes the current operational state of this storage processor.

This measure will be reported only if the API provides a detailed operational state.

Typically, the detailed state will describe why the storage processor is in a particular operational state. For instance, if the Operational status measure reports the value Stopping for a storage processor, then this measure will explain why that storage processor is being stopped.

The values that this measure can report and their corresponding numeric values are discussed in the table below:

Measure Value	Numeric Value
Online	0
Success	1
Power Saving Mode	2
Write Protected	3
Write Disabled	4
Not Ready	5
Removed	6
Rebooting	7
Offline	8
Failure	9

Note:

By default, this measure reports the Measure Values discussed above to indicate the detailed operational state of a storage processor. In the graph of this measure however, detailed operational states are represented using the numeric equivalents only.

Data transmitted

Indicates the rate at which data was transmitted by this storage processor.

MB/Sec

IOPS

Indicates the rate at which I/O operations were performed on this storage processor.

IOPS

Compare the value of this measure across storage processorsto know which storage processor handled the maximum number of I/O requests and which handled the least. If the gap between the two is very high, then it indicates serious irregularities in load-balancing across storage processors.

You may then want to take a look at the Reads and Writes measures to understand what to fine-tune – the load-balancing algorithm for read requests or that of the write requests.

Reads

Indicates the rate at which read operations were performed on this storage processor.

Reads/Sec

Compare the value of this measure across storage processors to know which storage processor handled the maximum number of read requests and which handled the least.

Writes

Indicates the rate at which write operations were performed on this storage processor.

Writes/Sec

Compare the value of this measure across storage processors to know which storage processor handled the maximum number of write requests and which handled the least.

Data reads

Indicates the rate at which data is read from this storage processor.

MB/Sec

Compare the value of these measures across storage processors to identify the slowest storage processor in terms of servicing read and write requests (respectively).

Data writes

Indicates the rate at which data is written to this storage processor.

MB/Sec

Average read size

Indicates the amount of data read from this storage processor per I/O operation

MB/Op

Compare the value of these measures across storage processors to identify the slowest storage processor in terms of servicing read and write requests (respectively).

Average write size

Indicates the amount of data written to this storage processor per I/O operation.

MB/Op

Read hit

Indicates the percentage of read requests that were serviced by the cache of this storage processor.

Percent

A high value is desired for this measure. A very low value is a cause for concern, as it indicates that cache usage is very poor; this in turn implies that direct storage processor accesses, which are expensive operations, are high.

Write hit

Indicates the percentage of write requests that were serviced by the cache of this storage processor.

Percent

High water flushes

Indicates the count of times data was flushed out of the write cache of this storage processor because a high watermark was violated.

Number

To regulate cache usage, watermark levels can be set using Navisphere Manager, Let’s assume your Low Watermark (LWM) is set at 60% and your High Watermark (HWM) is at 80%. In this scenario, Clariion Algorithms will try to keep your cache levels between 60% and 80% since those are defined as the low and high watermarks.

If for some reason the cache exceeds 80% occupancy (HWM), Forced Flushing kicks in disabling all the write cache in the Clariion.

Idle water flushes

Indicates the count of times data was flushed out of the write cache of this storage processor via idle cache flushing.

Number

When a host is writing data to the connected Clariion Disk via cache on the Clariion, the Clariion takes that data, writes it to cache and acknowledges back to the host that the data has been written to disk. This data can actually be sitting in the cache or being written to the disk when this acknowledgement goes out. The process happens in 64 Kilobyte chunks when the data is being transferred to the disk from the cache.

Due to large chunks of data coming in from the host, sometimes Idle Cache Flushing is not able to maintain the Low Watermark (LWM), in those cases Watermark Cache Flushing kicks in.

Low water flushes

Indicates the count of times data was flushed out of the write cache of this storage processor because a low watermark was violated.

Number

Due to large chunks of data coming in from the host, sometimes Idle Cache Flushing is not able to maintain the Low Watermark (LWM), in those cases Watermark Cache Flushing kicks in.

Write flushes

Indicates the number of requests to flush the write cache of this storage processor.

Number

Write cache flushed

Indicates the amount of data flushed out of the write cache of this storage processor.

Queue arrivals

Indicates the number of times a user request arrived while at least one other request was being processed by this storage processor.

Number

Queue length

Indicates the count of queue length by arrivals for this storage processor.

Number

A consistent increase in the value of this measure could indicate a processing bottleneck.

Dirty pages

Indicates the percentage of dirty pages currently in cache, that is, pages that have been modified in the SP’s write cache, but that have not yet been written to disk.

Percent

A high percentage of dirty pages means the cache is handling many write requests.