CPU Usage Spiking When Start DBMS On Oracle Linux 6 (Doc ID

CPU Usage Spiking When Start DBMS On Oracle Linux 6 (Doc ID 1995167.1)To Bottom

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In this Document

Symptoms Cause Solution References

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APPLIES TO:

Linux OS - Version Oracle Linux 6.0 and later
Linux x86-64

SYMPTOMS

Running Oracle RDBM 11.2.0.4 PSU4and CRS on Oracle Linux 6.6 and when instance starts and mounted orarootagent.bin uses a large amount of CPU and also high load.

The issue could be reproduced with UEK2/UEK3/RHCK when Oracle instance is started and DB is mounted.

Due to this issue,lot of CPU and load on the system is extremely high,cannot run the database.

CAUSE

The server has large number of LUNs/paths,and ASM volumes are managered by UDEV rules not ASMLib.

udevadm monitor shows when cpu usage spiking,there are lots udev changes.

UDEV [1427349083.901194] change /devices/virtual/block/dm-107 (block)
UDEV [1427349083.902318] change /devices/virtual/block/dm-47 (block)
UDEV [1427349083.902425] change /devices/virtual/block/dm-165 (block)
UDEV [1427349083.903671] change /devices/virtual/block/dm-56 (block)
UDEV [1427349083.904231] change /devices/virtual/block/dm-116 (block)
UDEV [1427349083.905124] change /devices/virtual/block/dm-66 (block)
UDEV [1427349083.912189] change /devices/virtual/block/dm-93 (block)
UDEV [1427349083.913394] change /devices/virtual/block/dm-105 (block)
UDEV [1427349083.915191] change /devices/virtual/block/dm-123 (block)
UDEV [1427349083.916158] change /devices/virtual/block/dm-170 (block)
UDEV [1427349083.920331] change /devices/virtual/block/dm-140 (block)
UDEV [1427349083.922613] change /devices/virtual/block/dm-244 (block)
UDEV [1427349083.928483] change /devices/virtual/block/dm-213 (block)

SOLUTION

1. Disable cpuspeed service

# service cpuspeed stop

# chkconfig cpuspeed off

2. Limit udev child creation by:

# udevadm --children-max=32

REFERENCES

CPU Usage Spiking When Start DBMS On Oracle Linux 6 (Doc ID 1995167.1) To Bottom

---

In this Document

Symptoms Cause Solution References

---

APPLIES TO:

Linux OS - Version Oracle Linux 6.0 and later
Linux x86-64

SYMPTOMS

Running Oracle RDBM 11.2.0.4 PSU4and CRS on Oracle Linux 6.6 and when instance starts and mounted orarootagent.bin uses a large amount of CPU and also high load.

The issue could be reproduced with UEK2/UEK3/RHCK when Oracle instance is started and DB is mounted.

Due to this issue,cannot run the database.

CAUSE

The server has large number of LUNs/paths,and ASM volumes are managered by UDEV rules not ASMLib.

udevadm monitor shows when cpu usage spiking,there are lots udev changes.

UDEV [1427349083.901194] change /devices/virtual/block/dm-107 (block)
UDEV [1427349083.902318] change /devices/virtual/block/dm-47 (block)
UDEV [1427349083.902425] change /devices/virtual/block/dm-165 (block)
UDEV [1427349083.903671] change /devices/virtual/block/dm-56 (block)
UDEV [1427349083.904231] change /devices/virtual/block/dm-116 (block)
UDEV [1427349083.905124] change /devices/virtual/block/dm-66 (block)
UDEV [1427349083.912189] change /devices/virtual/block/dm-93 (block)
UDEV [1427349083.913394] change /devices/virtual/block/dm-105 (block)
UDEV [1427349083.915191] change /devices/virtual/block/dm-123 (block)
UDEV [1427349083.916158] change /devices/virtual/block/dm-170 (block)
UDEV [1427349083.920331] change /devices/virtual/block/dm-140 (block)
UDEV [1427349083.922613] change /devices/virtual/block/dm-244 (block)
UDEV [1427349083.928483] change /devices/virtual/block/dm-213 (block)

SOLUTION

1. Disable cpuspeed service

# service cpuspeed stop

# chkconfig cpuspeed off

2. Limit udev child creation by:

# udevadm --children-max=32

REFERENCES

（编辑：李大同）

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