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ETERNUS SF Storage Cruiser 14.0 User's Guide

7.6.3 CM load error

Report detail:
The high overload condition of CM XX was detected.
The monitoring condition of the other object that it is related is as follows.
CM Monitoring Condition :   <- (1)
[CM0x00] Alarm
[CM0x01] Normal
[CM0x10] Normal
[CM0x11] Normal

Relevant Graph:
Please refer to the graph of CM busy rate. If the device has ROE, please refer to the graph of ROE busy rate.
Please refer to the IOPS graph of each LogicalVolume.   <- (2)

Action :
1. There is the possibility that I/O is focusing on RAIDGroups under the same CM.   <- (2)
   Please refer the monitoring condition of each CM and disperse the I/O to the RAIDGroup under the low overload CM.

2. The case of monitoring condition of each CM are all "Monitoring" or "Alarm",
It is possibility that CM number is insufficient to I/O demand.
Please consider GR hard extension or upgrade.
Descrition of (1)

Indicates the states of other CMs during the same time zone as the relevant CM detected a high load state. However, the state of each ROE is not indicated.

Alarm

An alarm log indicating a load error in the relevant CM is generated during the same time zone.

Monitoring

The CM is monitoring for alarm detection because the threshold has been exceeded several times although no events have been detected as an alarm.

Normal

The relevant CM did not cause a bottleneck during the same time zone.

Descrition of (2)

If only the relevant CM detected a high load state, I/O access is unevenly concentrated on the CM.
Refer to the IOPS graphs of RAIDGroups and LogicalVolumes and take measures such as distributing I/O loads of each CM.

Point

CM is put in high load state when a transaction is in contention with advanced copy.
In this case, review the operation mode so that advanced copy is executed in a time slot in which a transaction load is relatively small. Alternatively, if the same CM controls both the copy source and target volumes (RAIDGroups), use separate CMs to control the source and target volumes.