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Cache Write Policy does not changed from write-through to write-back after temperature has been recovered (Oceanstor 2600V3)

Publication Date:  2018-03-15 Views:  312 Downloads:  0

Issue Description

From beginning,

1. Data center HVAC failed

2. Ambient temperature rose

3. OceanStor 2600 V3 send alert below via email:


Dear OceanStor 2600_V3 users:

System Name: d3-autumn-2600-01

Location: IDC Duren Tiga

Customer Info:

ESN: 2102350SHY10H1000001

ID: 0xF0CE0008

Level: Major

Occurred At: 2018-03-13 03:52:46

Details: The temperature of Controller Enclosure (ID CTE0, SN

2102350SHY10H1000001) exceeds the upper limit. This leads to unstable system running, and cache write will be disabled.

Suggestions: Step1 Check whether alarms are generated indicating fan module faults.

    1.1 If yes, replace the faulty fan modules. If alarm Engine Temperature Exceeds the Upper Limit persists=>[Step2].

    1.2 If no=>[Step2].

Step2 Check whether heat dissipation channels are blocked.

    2.1 If yes, clear the heat dissipation channels. If alarm Engine Temperature Exceeds the Upper Limit persists=>[Step3].

    2.2 If no=>[Step3].

Step3 Check whether the ambient temperature is too high.

    3.1 If yes, lower the existing air conditioners' temperature or add more air conditioners. If alarm Engine Temperature Exceeds the Upper Limit persists=>[Step4].

    3.2 If no=>[Step4].

Step4 Collect related information and contact technical support engineers.



4. Data center HVAC fixed.

5. Ambient temperature return to normal.

6. Cleared the alarm via the web UI.

7. Checking via CLI:


admin:/>change user_mode current_mode user_mode=developer developer:/>show cache global


  Cache Local Controller ID             : 0

  Cache Mirror Controller ID            : 1

  Cache Write Protect                   : 0

  Volume Cache Mirror Fault             : yes

  Stripe Cache Mirror Fault             : yes

  Volume Cache Work Mode                : invalid

  Stripe Cache Work Mode                : invalid

  All Stripe Cache Write Through        : yes

  All Volume Cache Write Through        : yes

  All Stripe Cache Mirror Disable       : no

  All Volume Cache Mirror Disable       : no

  All Cache WriteHoleLog Open           : yes

  All Cache Asyncprefetch Open          : yes

  Global Cache Destage Enable           : yes

  Force Alloc Quota Flag Enable         : no

  Async Prefetch Max Req Concurrent     : 1024

  Async Prefetch Current Req Concurrent : 0

  Cache Update State                    : 2

  Cache Command Current Number          : 0

  VNode 0 Mirror Node ID                : 1

  VNode 1 Mirror Node ID                : 1

  VNode 2 Mirror Node ID                : 65535

  VNode 3 Mirror Node ID                : 65535


Cache write policy still remains as write-through mode, it suppose to change back to write-back mode

Handling Process

Check through system logs

Root Cause

A software defect in version lower than V300R005C00SPH307.


  1. Log in to storage CLI
  2. Change to developer mode change user_mode current_mode user_mode=developer
  3. Perform the following command:
    1. change system write_through_policy write_through_switch=Disable
    2. change system write_through_policy write_through_switch=Enable
  4. Check whether the write policy changed to “write-back”. (show cache global)
  5. Install the latest hot patch version V300R005C00SPH307, you can find the patch and installation guide in the following link: